The agricultural sector is traditionally recognized for its fundamental role in food production, ensuring the sustenance of populations worldwide. However, the scope of agricultural products extends beyond mere food supply, encompassing significant potential in the realm of energy production (Maina et al., 2019). Research has found that agriculture not only acts as an energy consumer but also as a producer of biofuels, particularly by using agricultural by-products as raw materials for renewable fuels (Praveen et al., 2021). The dual role of agricultural products as both food and fuel represents a pivotal intersection of agronomy and energy science, offering innovative solutions to contemporary challenges in energy security and sustainability.

Agricultural products serve a dual function in the modern economy. They not only provide essential nutrition through various foods but also contribute to biofuel production, which is crucial in the search for alternative energy sources. This dual functionality highlights the versatility and importance of agricultural output, making it a key component in addressing global energy needs while maintaining food security. Research indicates that biofuels derived from crops such as corn, sugarcane, and soybeans demonstrate the transformative potential of agriculture in the energy sector, driving a shift towards more sustainable and renewable energy resources (Lu and Yang, 2019; Munaiz et al., 2021). For instance, corn is used not only for food and feed but also for producing biofuel from its agricultural residues. Enhancing the energy content of crop residues, particularly the quality of cellulose biomass, can provide an alternative use for ethanol conversion. This dual use helps meet both food and energy demands simultaneously (Munaiz et al., 2021). Sugarcane is one of the primary crops for biofuel production, especially in Brazil. Although sugarcane is primarily used for sugar production in China, its cellulose biomass for fuel ethanol production is still under development. Research suggests that further modernizing planting and processing technologies can reduce production costs and increase efficiency to meet the growing demand for renewable energy (Lu and Yang, 2019).

Energy conversion and utilization in agriculture are critical for maximizing the potential benefits of agricultural products. Efficient energy conversion technologies ensure that the energy contained within agricultural biomass is effectively harnessed, whether for food processing, biofuel production, or other energy needs (Zhou et al., 2022). This efficiency is vital for reducing greenhouse gas emissions, improving energy independence, and fostering sustainable agricultural practices. Research has found significant variations in energy input among different crops, with vegetables and melons having the highest energy input (73.425 GJ/ha), while legume crops have the lowest energy input (6.13 GJ/ha). The primary energy sources are electricity, fertilizers, and diesel, contributing 46%, 20%, and 14%, respectively (Elsoragaby et al., 2019). Understanding and optimizing these processes is essential for developing integrated systems that support both food production and energy generation, thereby enhancing the overall resilience and sustainability of agricultural practices.

This study aims to explore the dual role of agricultural products as both food and fuel, examining the processes involved in energy conversion and utilization. It focuses on reviewing the current research status on using agricultural products to produce biofuels and its impact on the global energy landscape, analyzing the technological advancements and challenges in energy conversion in agriculture. Additionally, it proposes strategies to optimize the dual use of agricultural products to achieve a balance between food security and energy sustainability. Through this comprehensive analysis, the study seeks to contribute to the broader discussion on sustainable agriculture and renewable energy, providing insights and recommendations for future research and policy development.

1 Historical Context and Evolution

1.1 Traditional uses of agricultural products for food

The dual role of agricultural products as both food and fuel has deep historical roots, evolving significantly over time. Historically, agriculture has been the cornerstone of human civilization, providing the essential resources needed for sustenance and development. Crops such as wheat, rice, and maize have been staples in human diets for millennia, providing essential nutrients and calories necessary for survival and growth. Research shows that these crops are the main source of global food energy, accounting for over half of the calorie intake in the human diet (Yu and Tian, 2018; Giraldo et al., 2019). Traditional farming practices focused on maximizing grain yields to ensure food security and support growing populations. For instance, wheat has been a fundamental crop, with its grain being used to produce bread, a dietary staple in many cultures (Gabbanelli et al., 2021).

1.2 Evolution of bioenergy and biofuel production

The evolution of bioenergy and biofuel production marks a significant shift in the utilization of agricultural products. Initially, agricultural residues like wood and crop wastes were used as primary energy sources in the form of firewood and charcoal (Mohamed, 2020). However, with advancements in technology and increasing concerns over fossil fuel depletion and climate change, the focus has shifted towards more sustainable energy sources. The formal evolution of bioenergy and biofuel production began in the late 19th and early 20th centuries, driven by industrial advancements and the demand for alternative energy sources (Agarwal and Kumar, 2018). Biofuels, such as ethanol and biodiesel, have emerged as viable alternatives, produced from crops like corn and sugarcane (Mohamed, 2020).

The oil crisis of the 1970s further accelerated research and investment in biofuels, highlighting the vulnerability of relying solely on fossil fuels. By the end of the 20th century, technological advancements in enzymatic hydrolysis and fermentation processes made the conversion of agricultural biomass into ethanol and biodiesel more efficient. In recent years, the focus has expanded to second- and third-generation biofuels, which use non-food biomass and algae, respectively, addressing issues related to food security and land use (He et al., 2018; Robak and Balcerek, 2018). Additionally, the conversion of agricultural residues into biogas through anaerobic digestion has gained traction, offering a renewable energy source that can be integrated into existing agricultural systems (Gabbanelli et al., 2021).

1.3 Case studies of major shifts in agricultural product usage

Several case studies highlight the major shifts in the usage of agricultural products from solely food production to dual-purpose roles. Brazil's National Alcohol Program (ProAlcool), launched in the 1970s, marked a significant shift towards ethanol production from sugarcane. The ProAlcool program has yielded substantial economic benefits, driven technological innovation, and fostered social progress. Today, approximately 80% of Brazil's light vehicles run on bioethanol, significantly reducing the country's oil imports (Chandel et al., 2014).

The study explores wheat varieties in Argentina that are cultivated for dual purposes: food and fuel, focusing on the potential for biogas production. Gabbanelli et al. (2021) analyzed key traits such as grain yield, straw yield, and the efficiency of biogas conversion from straw in 36 wheat genotypes. The results showed that wheat from France exhibited the highest grain yield (Figure 1), while CIMMYT varieties had the lowest straw yield. The study found that the French varieties Baguette 31 and SNR Nogal performed best in terms of grain and straw yield, biogas conversion efficiency, and lodging resistance. These findings contribute to future wheat breeding programs, enhancing the potential of wheat as a dual-purpose crop (Gabbanelli et al., 2021). This dual-purpose approach not only enhances food security but also promotes the production of renewable energy.

Another significant development is the utilization of CO₂ for producing biofuels. Captured CO₂ can be converted into fuels such as methanol and methane, which can be used as energy sources. This approach not only mitigates greenhouse gas emissions but also provides a sustainable method for producing biofuels (Anwar et al., 2020). The integration of CO₂ utilization with agricultural practices, such as using algae for biofuel production, represents a forward-thinking strategy to address both energy and environmental challenges (Anwar et al., 2020).

The historical context and evolution of agricultural products reflect a transition from traditional food production to innovative dual-purpose roles, encompassing both food and fuel. This shift is driven by the need for sustainable energy solutions and the efficient use of agricultural resources.

2 Agricultural Products as Food

2.1 Nutritional value and benefits

Agricultural products, especially fruits and vegetables, are essential for human nutrition. Vegetables and fruits contain various phytonutrients, minerals, vitamins, and dietary fibers. These components not only have antioxidant and anti-inflammatory effects but also possess immunomodulatory, antibacterial, antiviral, and other functions. Common antioxidant phytochemicals include anthocyanins and carotenoids, such as β-carotene and lutein (Bule et al., 2020). Regular consumption of fruits and vegetables can prevent various non-communicable diseases, such as cancer, obesity, cardiovascular diseases, and others. The dietary fibers, minerals, vitamins, and secondary metabolites found in fruits and vegetables regulate cellular pathways in the human body, thereby reducing the risk of disease (Yahia et al., 2019).

Moreover, utilizing by-products from these agricultural products can further enhance their nutritional value. For instance, fruit and vegetable by-products such as peels, seeds, and pomace are rich in nutrients and can be incorporated into functional foods to improve health benefits and nutritional intake (Coman et al., 2020; Lau et al., 2021). These by-products can be used in various food products, including bakery and dairy items, to provide an alternative source of nutrients and support the global demand for functional foods (Lau et al., 2021).

2.2 Food security and sustainability

The increasing global population has led to a higher demand for food, making food security a critical issue. Efficient utilization of agricultural by-products can play a significant role in addressing food security by reducing waste and promoting sustainable consumption patterns. By converting non-utilized parts of fruits and vegetables into functional ingredients, the food industry can minimize waste and contribute to environmental sustainability (Lau et al., 2021). This approach aligns with the United Nations Sustainable Development Goals (SDGs) to ensure sustainable consumption and production patterns (Lau et al., 2021). Additionally, the production of bioenergy from agricultural products can provide a renewable energy source, further supporting sustainability efforts (Maina et al., 2019).

2.3 Major crops and their global consumption

Major crops such as cereals, vegetables, fruits, and oilseeds are widely consumed globally and play a crucial role in human diets. The energy input for the production of these crops varies significantly, with vegetable and melon crops requiring the highest energy input, while leguminous crops require the least (Elsoragaby et al., 2019). Cereal crops, including corn and rice, are among the most mechanized, with high energy inputs primarily from fertilizers and direct energy sources like electricity and diesel (Elsoragaby et al., 2019). The global consumption of these major crops underscores their importance in both food security and energy utilization, as they provide essential nutrients and serve as raw materials for bioenergy production (Elsoragaby et al., 2019; Maina et al., 2019).

By understanding the nutritional value, sustainability, and global consumption patterns of agricultural products, we can better appreciate their role in both food and energy sectors. This holistic approach ensures that agricultural practices contribute to both human health and environmental sustainability.

3 Agricultural Products as Fuel

3.1 Biofuel types and sources

Biofuels are derived from biomass, including agricultural crops and residues, and can be categorized into several types based on their source materials and production processes. The primary types of biofuels include ethanol, biodiesel, biogas, and cellulosic biofuels (Bartocci et al., 2020; Ambaye et al., 2021). Ethanol is produced through the fermentation of sugars found in crops like corn, sugarcane, and wheat. It is commonly used as a fuel additive to enhance octane levels and reduce carbon emissions in gasoline engines (Iodice et al., 2021; Sameeroddin et al., 2021). Biodiesel is made from vegetable oils, animal fats, or recycled cooking oils through a chemical process known as transesterification. It can be used in diesel engines, either pure or blended with petroleum diesel (Khairati, 2023). Biodiesel has excellent performance and environmental benefits, but during production, it is necessary to address issues related to free fatty acids and impurities to improve yield and quality (Ali and Khairuddin, 2023).

Biogas is produced through the anaerobic digestion of organic materials, including agricultural waste, manure, and food scraps. It primarily consists of 50%-75% methane and 25%-50% carbon dioxide, along with small amounts of hydrogen sulfide, hydrogen, ammonia, and trace gases. Methane can replace fossil fuels for heating, electricity generation, and transportation (Atelge et al., 2020). Cellulosic biofuels are derived from non-food biomass such as agricultural residues, grasses, and woody plants, utilizing advanced technologies to break down cellulose and hemicellulose into fermentable sugars (Benedetti et al., 2019). These biofuels represent a range of sources and technologies, each contributing to the diversification and sustainability of the energy supply.

3.2 Energy content and efficiency

The energy content and efficiency of biofuels vary depending on the type of biofuel and the feedstock used. Ethanol, for instance, has a lower energy content per gallon compared to gasoline, requiring adjustments in engine performance and fuel consumption (Iodice et al., 2021). However, ethanol blends can improve overall engine efficiency and reduce emissions.

Biodiesel has a higher energy content than ethanol and is closer to that of petroleum diesel. Its use can lead to better engine lubrication and reduced particulate emissions (Vergel-Ortega et al., 2021). The energy yield from biodiesel production is also favorable, with a high energy return on investment (EROI). Research has found that palm-sesame oil biodiesel produced through ultrasound-assisted transesterification performs well in engines, demonstrating advantages in reducing carbon dioxide and carbon monoxide emissions (Freitas et al., 2022). Biogas, with its high methane content, is an efficient fuel for electricity generation and heating. Its production from waste materials also provides additional environmental benefits by reducing methane emissions from landfills and manure storage. Cellulosic biofuels offer high energy efficiency due to the abundant availability of feedstocks and their minimal competition with food crops. Advances in enzymatic hydrolysis and fermentation technologies continue to improve the energy efficiency of cellulosic biofuel production.

Overall, the energy content and efficiency of biofuels depend on technological advancements, feedstock characteristics, and production processes, all of which are crucial for optimizing their use as sustainable energy sources.

3.3 Environmental impacts of biofuels

The environmental impacts of biofuels are multifaceted, encompassing both benefits and challenges. On the positive side, biofuels can significantly reduce greenhouse gas emissions compared to fossil fuels (Hanaki and Portugal-Pereira, 2018; Jeswani et al., 2020). The carbon dioxide released during biofuel combustion is offset by the carbon dioxide absorbed by the feedstock plants during their growth, creating a closed carbon cycle. Additionally, biofuels can reduce dependence on fossil fuels, enhance energy security, and provide a sustainable use for agricultural residues and waste materials. The use of non-food feedstocks, such as cellulosic materials, can also mitigate concerns related to food security and land use competition.

However, biofuel production can also pose environmental challenges. The cultivation of biofuel crops may lead to deforestation, loss of biodiversity, and soil degradation if not managed sustainably (Jeswani et al., 2020). Water usage for irrigation and processing can strain local water resources, particularly in regions with limited water availability. The use of fertilizers and pesticides in biofuel crop production can result in water pollution and negative impacts on ecosystems.

To address these challenges, it is essential to adopt sustainable agricultural practices, improve biofuel production technologies, and develop policies that promote environmental stewardship. By balancing the benefits and impacts, biofuels can play a significant role in achieving sustainable energy goals and reducing the environmental footprint of the energy sector.

4 Energy Conversion Processes

4.1 Photosynthesis and biomass production

Energy conversion processes are essential for transforming agricultural products into usable forms of energy. These processes leverage natural and technological mechanisms to convert biomass into biofuels and other energy carriers. Photosynthesis is the fundamental biological process by which green plants, algae, and certain bacteria convert light energy into chemical energy (Nimir and Zhou, 2018). During photosynthesis, these organisms absorb carbon dioxide (CO₂) from the atmosphere and water (H₂O) from the soil, using sunlight to produce glucose (C₆H₁₂O₆) and oxygen (O₂). This process forms the basis for biomass production, as the glucose produced during photosynthesis is used to build plant tissues and generate energy for growth and development. The biomass accumulated through photosynthesis serves as the primary raw material for biofuel production. Crops such as corn, sugarcane, and soybeans, as well as non-food plants like switchgrass and algae, are cultivated specifically for their high biomass yield and energy content (Brandes et al., 2018; Peng et al., 2019).

Research has found that intercropping switchgrass in corn/soybean fields is economically viable under certain conditions, particularly in regions with significant crop yield variability. This has important implications for designing policies aimed at enhancing the sustainability of agricultural production (Brandes et al., 2018). Algae and bacteria perform photosynthesis under sunlight, storing chemical energy and serving as feedstocks for biofuels. Algae can grow in saltwater and produce various biofuels, including biodiesel, methane, ethanol, and hydrogen. Developing efficient production processes is crucial for the successful utilization of these systems (Kumar, 2019). Research indicates that algae, due to their high photosynthetic efficiency and oil content, are considered a significant future source of biofuels. Although the cost of microalgal fuels is high, genetic and metabolic engineering can enhance production efficiency (Peng et al., 2019).

4.2 Biochemical conversion methods

Biochemical conversion methods utilize biological processes to transform biomass into biofuels. The most common biochemical conversion methods include fermentation and anaerobic digestion. The fermentation process involves converting sugars and starches in biomass into ethanol and other alcohols through microorganisms such as yeast. For example, corn and sugarcane can be fermented to produce ethanol. The ethanol produced through fermentation is often used as a fuel additive in gasoline to increase octane levels and reduce emissions (He et al., 2018). In addition to ethanol, fermentation can also produce other types of alcohols, such as butanol, which has a higher energy density and better blending properties than ethanol. The anaerobic digestion process involves the decomposition of organic matter by anaerobic bacteria under oxygen-free conditions, producing biogas that is primarily composed of methane (CH₄) and carbon dioxide (CO₂) (Goh et al., 2023). Typical feedstocks for anaerobic digestion include agricultural residues, manure, and food waste. The biogas produced can be used for heating, electricity generation, and as vehicle fuel. Besides energy production, the byproducts of anaerobic digestion—digestate and solid residues—can be used as efficient organic fertilizers to improve soil quality and structure.

The advantages of biochemical conversion methods lie in their ability to utilize a wide range of biomass feedstocks and their relatively low energy requirements compared to thermochemical methods. Moreover, biochemical conversion processes typically operate at lower temperatures and pressures, resulting in lower equipment and operating costs (Osman et al., 2021). Since these methods rely on the metabolic activities of microorganisms, researchers can use genetic engineering to modify microorganisms, enhancing their metabolic efficiency and adaptability to different feedstocks, thereby further increasing the yield and quality of biofuels. In recent years, the use of microalgae has emerged as a new area of research in biochemical conversion. Microalgae possess high photosynthetic efficiency and rapid growth characteristics, and their cells are rich in lipids and carbohydrates that can be converted into biofuels through fermentation and other biochemical methods. Cultivating microalgae does not require fertile land and freshwater resources, making it a biomass feedstock with minimal environmental impact and significant potential (Meng et al., 2019; Colomer-Vidal et al., 2021).

Biochemical conversion methods, by leveraging the natural metabolic processes of microorganisms, effectively transform various types of biomass into high-value biofuels and byproducts, offering broad application prospects and significant environmental benefits. In the future, with continuous technological advancements and widespread application, biochemical conversion methods are expected to play a more important role in the global energy structure.

4.3 Thermochemical conversion methods

Thermochemical conversion methods use heat and chemical reactions to convert biomass into biofuels and other energy carriers. The main thermochemical conversion methods include pyrolysis, gasification, and direct combustion. Pyrolysis process involves heating biomass in the absence of oxygen to decompose it into bio-oil, syngas (a mixture of carbon monoxide and hydrogen), and char (Sieradzka et al., 2020). The bio-oil can be further refined into biofuels, while syngas can be used for electricity generation or as a feedstock for chemical production. Pyrolysis operates at temperatures between 300 °C and 600 °C (Mensah et al., 2022). Gasification process converts biomass into syngas through partial oxidation at high temperatures (above 700 °C). The syngas produced can be used directly for electricity generation or further processed into liquid fuels via the Fischer-Tropsch synthesis. Gasification is highly efficient and can handle a variety of biomass feedstocks (Amin et al., 2022). Direct combustion is the simplest thermochemical conversion method, involving the burning of biomass to produce heat, which can be used for power generation or industrial processes (Bajpai et al., 2020). Although direct combustion is widely used, it has lower efficiency compared to other thermochemical methods and, if not managed properly, can lead to higher emissions.

The advantages of thermochemical conversion methods lie in their ability to produce a diverse range of energy products and their potential for integration with existing industrial processes. However, compared to biochemical methods, they typically require higher capital investment and more complex technologies. In summary, energy conversion processes are crucial for transforming agricultural biomass into biofuels and other energy carriers. Photosynthesis provides the basic biomass, while biochemical and thermochemical methods offer various pathways to convert this biomass into usable energy forms. Understanding and optimizing these processes are essential for maximizing the energy potential of agricultural products and supporting their dual role as both food and fuel.

5 Utilization of Agricultural Products for Energy

5.1 Direct combustion and co-firing

Direct combustion is the simplest and most traditional method of utilizing biomass for energy. In this process, biomass such as wood, crop residues, and other organic materials are burned to produce heat, which can be used for space heating, industrial processes, or electricity generation. This method has been used for centuries, particularly in rural and developing regions where access to other forms of energy is limited.

Co-firing is an advanced application of direct combustion, where biomass is burned alongside coal in existing coal-fired power plants. This approach allows for the reduction of greenhouse gas emissions and the efficient use of existing infrastructure. By integrating biomass with coal, co-firing can reduce the carbon footprint of power generation and provide a transitional pathway towards more sustainable energy systems (Li et al., 2018). Biomass sources for direct combustion and co-firing include wood, crop residues, and animal manure. These materials can be processed into fuelwood, charcoal, or briquettes to enhance their energy density and ease of transport (Maina et al., 2019).

5.2 Bioethanol and biodiesel production

Bioethanol and biodiesel are two of the most common biofuels derived from agricultural products. Bioethanol is primarily produced through the fermentation of sugars and starches found in crops such as corn, sugarcane, and wheat. The production process involves milling the feedstock to release fermentable sugars, fermenting these sugars with yeast, and then distilling the ethanol (Limayem and Ricke, 2019; Kumar and Verma, 2021). Bioethanol is commonly blended with gasoline to create E10 (10% ethanol) or E85 (85% ethanol) fuel blends, which can be used in conventional gasoline engines. The use of bioethanol reduces greenhouse gas emissions and enhances fuel octane levels, contributing to cleaner combustion. Research has found that using ethanol-gasoline blends ranging from 10% to 85% increases the fuel's octane rating while also increasing total hydrocarbon emissions and reducing the emissions of aromatic BTEX compounds (Schifter et al., 2018).

Biodiesel is produced via the transesterification process, which involves reacting vegetable or animal fats and oils with short-chain alcohols (typically methanol or ethanol) in the presence of a catalyst. This process yields biodiesel and glycerol as by-products (Atabani et al., 2018; Karmakar et al., 2019). Biodiesel can be used in pure form (B100) or blended with petroleum diesel (e.g., B20, which is 20% biodiesel) in diesel engines. Biodiesel provides benefits such as lower emissions of particulates, carbon monoxide, and hydrocarbons, as well as enhanced lubricity, which can extend engine life. The production of these biofuels not only provides a renewable energy source but also helps in reducing carbon emissions and dependence on fossil fuels (Maina et al., 2019; Anwar et al., 2020).

5.3 Advanced biofuels and future prospects

Advanced biofuels, also known as second and third-generation biofuels, represent the next frontier in bioenergy, utilizing non-food biomass and innovative technologies to overcome some of the limitations associated with traditional biofuels. Second-generation biofuels are derived from lignocellulosic biomass, including agricultural residues (e.g., straw, husks), forestry waste, and dedicated energy crops (e.g., Panicum virgatum) (Li et al., 2023; Shrestha et al., 2023). Technologies such as enzymatic hydrolysis and gasification convert these complex feedstocks into fermentable sugars or syngas, which can then be processed into ethanol, biodiesel, or other biofuels. Second-generation biofuels offer higher yields and lower environmental impacts compared to first-generation biofuels, as they do not compete directly with food crops for land and resources. Algae-based biofuels are a promising third-generation biofuel technology. Algae have high growth rates and can be cultivated in a variety of environments, including saline or wastewater, without competing for arable land. Algae can produce significant amounts of lipids, which can be converted into biodiesel, as well as carbohydrates that can be fermented into bioethanol (Anwar et al., 2020; Chiaramonti and Talluri, 2020; Zhang et al., 2022). Research is ongoing to optimize algae cultivation, harvesting, and conversion processes to make third-generation biofuels economically viable and scalable.

The future of biofuels lies in integrating advanced technologies, improving feedstock supply chains, and enhancing conversion efficiencies. Innovations such as genetic engineering, synthetic biology, and biorefinery concepts aim to optimize biomass yield, reduce costs, and increase the sustainability of biofuel production. Policy support, investment in research and development, and international cooperation are crucial to advancing biofuel technologies and realizing their full potential as a sustainable energy source.

The utilization of agricultural products for energy through direct combustion, bioethanol and biodiesel production, and advanced biofuels presents a sustainable alternative to fossil fuels. These methods not only contribute to energy sustainability but also offer environmental and economic benefits. However, careful consideration of potential conflicts with food production and land use changes is essential to ensure a balanced approach to bioenergy development.

6 Balancing Food and Fuel Production

6.1 Land use considerations and conflicts

Balancing the dual roles of agricultural products for food and fuel production necessitates careful land use planning to avoid conflicts and ensure sustainability. The introduction of bioenergy markets, such as those for cellulosic ethanol, can have significant implications for land use. For instance, converting low-quality agricultural land to perennial biomass crops can increase biofuel feedstock production without severely impacting soil quality. However, this may lead to intensified food production on high-quality land, potentially degrading soil health if not managed properly (Liu et al., 2018). Additionally, organic farming systems that avoid food-feed competition by using grass from permanent pastures and food industry by-products can optimize land use for food production while maintaining environmental performance (Karlsson and Röös, 2019).

6.2 Crop selection and rotational strategies

Selecting appropriate crops and implementing effective rotational strategies are crucial for balancing food and fuel production. Organic farming systems, which incorporate leguminous forage crops to supply nitrogen and control weeds, can produce substantial amounts of grass biomass suitable for feeding ruminants. This approach not only supports food production but also enhances soil health through improved nutrient cycling (Karlsson and Röös, 2019). Moreover, converting low-quality land to perennial biomass crops for bioenergy can be a viable strategy, provided that conservation tillage methods are adopted to mitigate negative impacts on soil cover (Liu et al., 2018).

6.3 Impact on soil health and biodiversity

The impact of agricultural practices on soil health and biodiversity is a critical consideration in balancing food and fuel production. Harvesting crop residues for bioenergy can reduce soil cover, potentially leading to soil degradation. However, adopting conservation tillage methods can help maintain soil quality (Liu et al., 2018). Organic farming systems that utilize grass from permanent pastures and temporary grass-clover leys can enhance soil health by reducing nutrient losses and improving soil structure (Karlsson and Röös, 2019). Research has found that compared to tilled soil, grass-clover grasslands significantly increase earthworm numbers, permeability, macropore flow, and saturated hydraulic conductivity while reducing soil compaction. These improvements lead to higher wheat yields under both flood and normal conditions (Berdeni et al., 2021). Additionally, careful land use planning is essential to prevent the conversion of high-quality land covered by forest, shrub, and grass to agricultural production, which could negatively impact soil quality and biodiversity (Liu et al., 2018).

6.4 Socio-economic factors influencing crop allocation

Socio-economic factors play a significant role in determining crop allocation for food and fuel production. The introduction of bioenergy markets can provide economic incentives for farmers to produce biomass crops, potentially leading to shifts in land use and crop selection (Liu et al., 2018). In organic farming systems, the allocation of grass biomass for animal feed versus food production can influence overall food output and environmental impacts. For example, using all grass biomass for animal feed can increase total food output but also result in higher climate impacts due to increased livestock production (Karlsson and Röös, 2019). Therefore, socio-economic considerations, including market demands and policy incentives, must be carefully balanced to optimize crop allocation for both food and fuel production.

Balancing food and fuel production involves addressing land use conflicts, optimizing crop selection and rotational strategies, maintaining soil health and biodiversity, and considering socio-economic factors. By integrating these considerations into agricultural practices and policy frameworks, it is possible to achieve a sustainable and equitable balance between the dual roles of agricultural products as food and fuel. This holistic approach is essential for ensuring food security, environmental sustainability, and economic resilience in the face of growing global challenges.

7 Case Studies

7.1 Success studies of integrated food and fuel systems

Brazil is a global leader in sugarcane ethanol production, accounting for 30% of the world's fuel ethanol production. In 2019, Brazil produced approximately 8.6 billion gallons of ethanol, second only to the United States (Karp et al., 2021). The production process of Brazilian sugarcane ethanol is highly energy-efficient, contributing significantly to reducing dependence on petroleum and lowering carbon dioxide emissions. This biofuel can be used as 100% ethanol or blended with gasoline, helping Brazil establish a 46% renewable energy matrix. Additionally, with the advancement of new technologies and policies, such as the development of second-generation ethanol (2G ethanol), Brazil's ethanol production is expected to continue growing, bringing positive environmental and socio-economic impacts (Karp et al., 2021) (Figure 2).

Research has found that sugarcane cultivation in Brazil has not directly led to deforestation, as most of the expansion occurs on long-used pastures, reducing land competition between food production and sugarcane cultivation (Follador et al., 2021). Integrating sugarcane cultivation with livestock production has improved land productivity by using sugarcane by-products as feed, avoiding the need for new deforestation (Souza et al., 2019). Additionally, Brazil has introduced a new variety of sugarcane called "energy cane," which can triple biomass yield per unit area and significantly reduce production costs. This technological innovation has driven further growth in ethanol production (Grassi and Pereira, 2019). Furthermore, the Brazilian government has promoted the biofuel industry through the "RenovaBio" policy, which establishes a decarbonization credit mechanism linked to the carbon intensity of biofuels. This policy helps increase ethanol production and ensures its market demand (Klein et al., 2019). The success of Brazilian sugarcane ethanol can be attributed to pioneering biofuel policies and significant scientific and technological advancements. These policies and technological improvements have not only enhanced the environmental benefits of ethanol production but also fostered socio-economic development by creating jobs and promoting economic growth in rural areas (Karp et al., 2021).

Another example is corn. The United States is a major producer of bioethanol, primarily derived from corn. This biofuel holds significant importance for energy policy, rural development, and environmental sustainability. Corn-based bioethanol is considered a first-generation biofuel, utilizing hexose sugars for fermentation. The production process includes grinding, cooking, and liquefaction, followed by fermentation using yeast strains such as Saccharomyces cerevisiae. This method has been industrialized in both developed and developing countries to meet the growing demand for bioethanol. Corn-based bioethanol not only contributes to energy security but also has positive impacts on rural economies and the environment (Mohanty and Swain, 2019).

7.2 Challenges faced in specific regions or countries

Despite some successes, many regions and countries still face significant challenges in balancing food and fuel production. For example, in Sub-Saharan Africa, the promotion of biofuel production has sometimes led to land use conflicts and food security issues (Chanceline, 2019). Large-scale biofuel projects have been criticized for displacing small farmers and reducing the land available for food crops. These projects often prioritize biofuel production for export over local food needs, further exacerbating food insecurity (Chanceline, 2019; Ahmed, 2021). Moreover, research has found that local communities face numerous problems when biofuel plantations are closed or abandoned, including unemployment, issues with the return of land rights, and difficulties in ecological restoration. These issues highlight the negative impacts of biofuel plantation closures on sustainable development (Ahmed, 2021).

India is another case where the promotion of biofuel crops has faced difficulties. Initially hailed as a promising biofuel crop for arid regions, jatropha plantations often failed due to low yields and inadequate supporting infrastructure. When jatropha planting was introduced in southern India, it was expected to increase biofuel self-sufficiency and improve the livelihoods of marginal farmers. However, the project failed due to implementation flaws at all levels, from the government to the farmers (Gopakumar, 2020). Another study found that jatropha cultivation under semi-arid conditions in Botswana required supplementary irrigation to achieve satisfactory yields. This suggests that jatropha cultivation in low-rainfall areas like India also faces similar water management challenges (Moseki et al., 2019).

7.3 Lessons learned from the project

From past and ongoing projects, we can draw several important lessons on balancing food and fuel production. Among these, a localized approach is crucial. Successfully integrating food and fuel systems requires a deep understanding of local agricultural practices, environmental conditions, and socioeconomic contexts. Projects must be tailored to meet the specific needs and capacities of the communities involved. Stakeholder involvement is also vital. Engaging farmers, local communities, policymakers, and other stakeholders in the planning and implementation stages ensures that projects address local concerns and priorities. Transparent and inclusive decision-making processes help gain community support and enhance the sustainability of projects. Additionally, sound policy frameworks and incentives are critical for supporting integrated food and fuel systems. Governments play a key role in providing the necessary infrastructure, research and development, and financial incentives. Policies should aim to balance the benefits of biofuel production while ensuring food security and environmental protection.

Case studies of integrated food and fuel systems provide valuable insights into the complexities and opportunities of balancing agricultural products for food and energy. The success stories of sugarcane and maize showcase the potential for synergy, while the challenges faced in Sub-Saharan Africa and India highlight the need for careful planning and context-specific solutions. Stakeholder engagement, supportive policies, and adaptive management are crucial in achieving sustainable and equitable food and fuel production systems.

8 Future Prospects and Innovations

8.1 Emerging technologies in agricultural energy conversion

Emerging technologies in agricultural energy conversion are set to revolutionize the way biomass is transformed into energy. Innovations such as advanced bio-refineries, which integrate multiple conversion processes, enable the efficient production of a variety of biofuels and bio-based products from agricultural residues and non-food crops. The development of second-generation biofuels, which use lignocellulosic biomass, and third-generation biofuels from algae, offer higher energy yields and lower environmental impacts compared to traditional biofuels (Li et al., 2023; Shrestha et al., 2023). Advancements in enzymatic hydrolysis and genetic engineering are improving the efficiency of biofuel production by breaking down complex carbohydrates into fermentable sugars more effectively. Additionally, technologies like anaerobic digestion and pyrolysis are being optimized to enhance biogas production and bio-oil yield, respectively (Anwar et al., 2020). These innovations are crucial for maximizing the energy potential of agricultural products while minimizing their ecological footprint.

8.2 Potential for genetically modified crops in dual-use

Genetically modified (GM) crops hold significant potential for enhancing the dual-use of agricultural products as food and fuel (Paul et al., 2018). GM crops can be engineered to increase biomass yield, improve resistance to pests and diseases, and tolerate harsh environmental conditions, making them ideal candidates for biofuel production. For example, GM maize and sugarcane varieties have been developed to produce higher starch and sugar content, which can be efficiently converted into bioethanol (Khan et al., 2019).

Moreover, GM crops can be designed to possess traits that benefit both food and fuel applications. For instance, crops engineered for higher nutritional value can simultaneously provide superior feedstock for biofuel production. The development of multi-functional crops that serve both purposes without compromising food security is a key area of research. However, the adoption of GM crops must be carefully managed to address potential environmental and socio-economic concerns.

8.3 Prospects for sustainable and resilient food-fuel systems

The future prospects for sustainable and resilient food-fuel systems depend on integrated approaches that balance the needs of food production and energy generation. Agroecological practices, such as crop diversification, agroforestry, and conservation agriculture, play a critical role in enhancing system resilience and sustainability. These practices improve soil health, increase biodiversity, and reduce dependency on chemical inputs, creating a more robust agricultural landscape.

The integration of renewable energy technologies, such as solar and wind power, with biofuel production systems can further enhance sustainability. For example, solar-powered irrigation and biogas-powered machinery reduce reliance on fossil fuels and decrease greenhouse gas emissions. Developing localized, community-based biofuel production systems can also enhance energy security and provide economic opportunities for rural communities.

9 Concluding Remarks

The dual role of agricultural products as food and fuel presents both opportunities and challenges. This study has explored the multifaceted role of agricultural products in providing both food and energy, highlighting several key points. Agricultural products have significant nutritional value, contributing to human health and well-being through a diverse range of foods. Food security and sustainability are critical issues, requiring balanced approaches to land use, crop selection, and agricultural practices. Biofuels such as bioethanol and biodiesel offer renewable energy solutions, with emerging technologies enhancing efficiency and reducing environmental impacts. Balancing food and fuel production involves addressing land use conflicts, optimizing crop rotations, maintaining soil health, and considering socio-economic factors. Successful integrated food and fuel systems, like those in Brazil and Kenya, demonstrate the potential for synergy, while challenges in regions like sub-Saharan Africa and India underscore the need for careful planning. Future prospects include the development of advanced biofuels, genetically modified crops, and sustainable food-fuel systems, supported by effective policies and stakeholder engagement.

The findings of this study suggest several directions for future research and development. Technological innovations are crucial, particularly continued research into advanced biofuel technologies, such as cellulosic biofuels and algae-based fuels. Improving conversion efficiencies and reducing costs will make these technologies more viable. Genetic engineering holds promise for developing crops with enhanced yields, resistance to environmental stress, and suitability for both food and fuel applications, significantly contributing to sustainability. Investigating and promoting sustainable agricultural practices that enhance soil health, biodiversity, and resilience will support long-term food and energy security. Further research into integrated food-fuel systems, including agroforestry and mixed cropping, can provide models for sustainable agricultural landscapes. Analyzing the effectiveness of policy interventions and developing frameworks that balance food and fuel production while ensuring environmental and socio-economic sustainability is essential for advancing this field.

The dual role of agricultural products as both food and fuel represents a dynamic and evolving field with the potential to address some of the most pressing global challenges. As the world grapples with the need for sustainable energy sources and food security, agricultural products offer a unique opportunity to meet these demands in a complementary manner. The integration of advanced technologies, sustainable practices, and supportive policies can create resilient systems that provide both nourishment and energy. By recognizing the interconnectedness of food and energy systems, stakeholders can develop strategies that optimize the use of agricultural resources, enhance environmental sustainability, and support economic development. The future of agricultural products lies in their ability to adapt and innovate, ensuring that they continue to play a vital role in sustaining life and powering progress.

Acknowledgments

The BioSci Publisher appreciate the feedback from two anonymous peer reviewers on the manuscript of this study, whose careful evaluation and constructive suggestions have contributed to the improvement of the manuscript.

Conflict of Interest Disclosure

The author affirm that this research was conducted without any commercial or financial relationships that could be construed as a potential conflict of interest.

Reference

Agarwal S., and Kumar A., 2018, Historical development of biofuels, 17-45.

https://doi.org/10.1007/978-81-322-3763-1_2

Ahmed A., 2021, Biofuel feedstock plantations closure and land abandonment in Ghana: New directions for land studies in Sub-Saharan Africa, Land Use Policy, 107: 105492.

https://doi.org/10.1016/J.LANDUSEPOL.2021.105492

Ali N., and Khairuddin N., 2023, Biodiesel production from waste cooking oil using heterogeneous CaO/Zn catalyst: yield and reusability performance, Chiang Mai Journal of Science, 50(6): e2023070.

https://doi.org/10.12982/cmjs.2023.070

Ambaye T., Vaccari M., Bonilla-Petriciolet A., Prasad S., Hullebusch E., and Rtimi S., 2021, Emerging technologies for biofuel production: A critical review on recent progress, challenges and perspectives.. Journal of environmental management, 290: 112627.

https://doi.org/10.1016/j.jenvman.2021.112627

Amin M., Munir S., Iqbal N., Wabaidur S., and Iqbal A., 2022, The conversion of waste biomass into carbon-supported iron catalyst for syngas to clean liquid fuel production, Catalysts, 12(10): 1234

https://doi.org/10.3390/catal12101234

Anwar M., Fayyaz A., Sohail N., Khokhar M., Baqar M., Yasar A., Rasool K., Nazir A., Raja M., Rehan M., Aghbashlo M., Tabatabaei M., and Nizami A., 2020, CO₂ utilization: Turning greenhouse gas into fuels and valuable products, Journal of environmental management, 260L 110059.

https://doi.org/10.1016/j.jenvman.2019.110059

Atabani A.E., Silitonga A.S., Ong H.C., Mahlia T.M.I., Masjuki H.H., Badruddin I.A., and Fayaz H., 2018, Non-edible vegetable oils: A critical evaluation of oil extraction, fatty acid compositions, biodiesel production, characteristics, engine performance, and emissions production, Renewable and Sustainable Energy Reviews, 90: 320-339.

https://doi.org/10.1016/j.rser.2018.03.011

Atelge M., Atelge M., Krisa D., Kumar G., Eskicioglu C., Nguyen D., Chang S., Atabani A., Al-Muhtaseb A., and Ünalan S., 2020, Biogas production from organic waste: recent progress and perspectives, Waste and Biomass Valorization, 11: 1019-1040.

https://doi.org/10.1007/S12649-018-00546-0

Bajpai P., 2020, Biomass conversion processes. Biomass to Energy Conversion Technologies, 41-151.

https://doi.org/10.1016/b978-0-12-818400-4.00005-0

Bartocci P., Tschentscher R., Yan Y., Yang H., Bidini G., and Fantozzi F., 2020, Biofuels: Types and Process Overview, 1-36.

https://doi.org/10.1007/978-981-13-8637-4_1

Benedetti M., Vecchi V., Betterle N., Natali A., Bassi R., and Dall’Osto L., 2019, Design of a highly thermostable hemicellulose-degrading blend from Thermotoga neapolitana for the treatment of lignocellulosic biomass, Journal of biotechnology, 296: 42-52.

https://doi.org/10.1016/j.jbiotec.2019.03.005

Berdeni D., Turner A., Grayson R., Llanos J., Holden J., Firbank L., Lappage M., Hunt S., Chapman P., Hodson M., Helgason T., Watt P., and Leake J., 2021, Soil quality regeneration by grass-clover leys in arable rotations compared to permanent grassland: Effects on wheat yield and resilience to drought and flooding, Soil and Tillage Research, 212: 105037.

https://doi.org/10.1016/J.STILL.2021.105037

Brandes E., Plastina A., and Heaton E., 2018, Where can switchgrass production be more profitable than corn and soybean? An integrated subfield assessment in Iowa, USA. GCB Bioenergy, 10.

https://doi.org/10.1111/gcbb.12516

Bule M., Issa I., Khan F., Shah M., and Niaz K., 2020, Development of new food products based on phytonutrients, 197-216.

https://doi.org/10.1016/b978-0-12-815354-3.00008-3

Chanceline B., 2019, Land grabbing and its impact on food security in Sub-Saharan Africa, SocioEconomic Challenges, 3(4): 72-85.

https://doi.org/10.21272/sec.3(4).72-85.2019

Chandel A., Junqueira T., Morais E., Gouveia V., Cavalett O., Rivera E., Geraldo V., Bonomi A., and Silva S., 2014, Techno-economic analysis of second-generation ethanol in Brazil: competitive, complementary aspects with first-generation ethanol, 1-29.

https://doi.org/10.1007/978-3-319-05020-1_1

Chiaramonti D., and Talluri G, 2020, Technical review and economic evaluation of biofuels from microalgae, Applied Energy, 259: 114112.

https://doi.org/10.1016/j.apenergy.2019.114112

Colomer-Vidal P., Jiang L., Mei W., Luo C., Lacorte S., Rigol A., and Zhang G., 2021, Plant uptake of perfluoroalkyl substances in freshwater environments (Dongzhulong and Xiaoqing Rivers, China), Journal of hazardous materials, 421: 126768.

https://doi.org/10.1016/j.jhazmat.2021.126768

Coman V., Teleky B., Mitrea L., Martău G., Szabo K., Călinoiu L., and Vodnar D., 2020, Bioactive potential of fruit and vegetable wastes, Advances in food and nutrition research, 91: 157-225.

https://doi.org/10.1016/BS.AFNR.2019.07.001

Elsoragaby S., Yahya A., Mahadi M., Nawi N., and Mairghany M., 2019, Energy utilization in major crop cultivation, Energy, 173: 1285-1303.

https://doi.org/10.1016/J.ENERGY.2019.01.142

Follador M., Soares-Filho B., Philippidis G., Davis J., Oliveira A., and Rajão R., 2021, Brazil’s sugarcane embitters the EU-Mercosur trade talks, Scientific Reports, 11.

https://doi.org/10.1038/s41598-021-93349-8

Freitas E., Guarieiro L., Silva M., Amparo K., Machado B., Guerreiro E., Jesus J., and Torres E., 2022, Emission and performance evaluation of a diesel engine using addition of ethanol to diesel/biodiesel fuel blend, Energies, 15(9): 2988.

https://doi.org/10.3390/en15092988

Gabbanelli N., Erbetta E., Smachetti M., Lorenzo M., Talia P., Ramírez I., Vera M., Durruty I., Pontaroli A., and Echarte M., 2021, Towards an ideotype for food-fuel dual-purpose wheat in Argentina with focus on biogas production, Biotechnology for Biofuels, 14.

https://doi.org/10.1186/s13068-021-01941-x

Giraldo P., Benavente E., Manzano-Agugliaro F., and Giménez E., 2019, Worldwide research trends on wheat and barley: a bibliometric comparative analysis, Agronomy, 9(7): 352.

https://doi.org/10.3390/AGRONOMY9070352

Goh H., Woon F., Moisik S., and Styles S., 2023, Contrastive alveolar/retroflex phonemes in Singapore mandarin bilinguals: comprehension rates for articulations in different accents, and acoustic analysis of productions, Language and speech, 238309231205012.

https://doi.org/10.1177/00238309231205012

Gopakumar L., 2020, Jatropha cultivation in South India – policy implications, 453-472.

https://doi.org/10.1007/978-3-030-42630-9_23

Grassi M., and Pereira G., 2019, Energy-cane and RenovaBio: Brazilian vectors to boost the development of Biofuels, Industrial Crops and Products, 129: 201-205.

https://doi.org/10.1016/J.INDCROP.2018.12.006

Hanaki K., and Portugal-Pereira J., 2018, The effect of biofuel production on greenhouse gas emission reductions, Biofuels and Sustainability, 53-71.

https://doi.org/10.1007/978-4-431-54895-9_6

He Y., Wu T., Wang X., Chen B., and Chen F., 2018, Cost-effective biodiesel production from wet microalgal biomass by a novel two-step enzymatic process, Bioresource technology, 268: 583-591.

https://doi.org/10.1016/j.biortech.2018.08.038

Iodice P., Amoresano A., and Langella G., 2021, A review on the effects of ethanol/gasoline fuel blends on NOX emissions in spark-ignition engines, Biofuel Research Journal, 8(4): 1465-1480.

https://doi.org/10.18331/brj2021.8.4.2

Jeswani H., Chilvers A., and Azapagic A., 2020, Environmental sustainability of biofuels: a review, Proceedings. Mathematical, Physical, and Engineering Sciences, 476.

https://doi.org/10.1098/rspa.2020.0351

Karlsson J., and Röös E., 2019, Resource-efficient use of land and animals—Environmental impacts of food systems based on organic cropping and avoided food-feed competition, Land Use Policy, 85: 63-72.

https://doi.org/10.1016/J.LANDUSEPOL.2019.03.035

Karmakar A., Karmakar S., and Mukherjee S., 2019, Properties of various plants and animals feedstocks for biodiesel production. Bioresource Technology, 101(19): 7201-7210.

https://doi.org/10.1016/j.biortech.2010.04.079

Karp S., Medina J., Letti L., Woiciechowski A., Carvalho J., Schmitt C., Penha R., Kumlehn G., and Soccol C., 2021, Bioeconomy and biofuels: the case of sugarcane ethanol in Brazil. Biofuels, 15.

https://doi.org/10.1002/bbb.2195

Khairati M., 2023, Biodiesel: an overview, International Journal of Research and Review, 10(11).

https://doi.org/10.52403/ijrr.20231127

Khan M., Khan I., and Yasmeen S., 2019, Genetically modified sugarcane for biofuels production: status and perspectives of conventional transgenic approaches, RNA interference, and genome editing for improving sugarcane for biofuels, Sugarcane Biofuels, 67-96.

https://doi.org/10.1007/978-3-030-18597-8_4

Klein B., Chagas M., Watanabe M., Bonomi A., and Filho R., 2019, Low carbon biofuels and the New Brazilian National Biofuel Policy (RenovaBio): A case study for sugarcane mills and integrated sugarcane-microalgae biorefineries, Renewable and Sustainable Energy Reviews, 115: 109365.

https://doi.org/10.1016/j.rser.2019.109365

Kumar S., and Verma A., 2021, Advanced bioethanol production technologies: Recent progress and future perspectives, Bioresource Technology, 320: 124423.

https://doi.org/10.1016/j.biortech.2020.124423

Kumar S., 2019, Algal Biomass to bio-energy: recent advances, Journal of Ecophysiology and Occupational Health, 19: 78-85.

https://doi.org/10.18311/jeoh/2019/23376

Lau K., Sabran M., and Shafie S., 2021, Utilization of Vegetable and Fruit By-products as Functional Ingredient and Food, Frontiers in Nutrition, 8.

https://doi.org/10.3389/fnut.2021.661693

Li J., Ye Y., and Yao J., 2023, Advances in the production of second-generation biofuels: A review, Renewable and Sustainable Energy Reviews, 152: 111652.

https://doi.org/10.1016/j.rser.2021.111652

Li L., Gao Y., Hu Z., Yuan Z., Day S., and Li H., 2018, Model test research of a semisubmersible floating wind turbine with an improved deficient thrust force correction approach, Renewable energy, 119: 95-105.

https://doi.org/10.1016/j.renene.2017.12.019

Limayem A., and Ricke S.C., 2019, Lignocellulosic biomass for bioethanol production: Current perspectives, potential issues and future prospects, Progress in Energy and Combustion Science, 38(4): 449-467.

https://doi.org/10.1016/j.pecs.2012.03.002

Liu J., Huffman T., and Green M., 2018, Potential impacts of agricultural land use on soil cover in response to bioenergy production in Canada, Land Use Policy, 75: 33-42.

https://doi.org/10.1016/J.LANDUSEPOL.2018.03.032

Lu Y., and Yang Y., 2019, Sugarcane biofuels production in China, Sugarcane Biofuels, 139-155.

https://doi.org/10.1007/978-3-030-18597-8_7

Maina M., Oluwole F., and Mukhtar U., 2019, Energy resource from agriculture: prospects and problems, ATBU Journal of Science, Technology and Education, 7: 118-128.

Meng J., Zhou Y., Liu S., Chen S., and Wang T., 2019, Increasing perfluoroalkyl substances and ecological process from the Yongding Watershed to the Guanting Reservoir in the Olympic host cities, China, Environment international, 133(Pt B): 105224.

https://doi.org/10.1016/j.envint.2019.105224

Mensah I., Ahiekpor J., Bensah E., Narra S., Amponsem B., and Antwi E., 2022, Recent development of biomass and plastic Co-Pyrolysis for syngas production, Chemical Science International Journal, 31(1): 41-59.

https://doi.org/10.9734/csji/2022/v31i130275

Mohamed N., 2020, Energy in agriculture, SpringerBriefs in Climate Studies, 27-46.

https://doi.org/10.1007/978-3-030-38010-6_4

Mohanty S., and Swain M., 2019, Bioethanol production from corn and wheat: food, fuel, and future, Bioethanol Production from Food Crops, 45-59.

https://doi.org/10.1016/B978-0-12-813766-6.00003-5

Moseki O., Murray-Hudson M., and Kashe K., 2019, Crop water and irrigation requirements of Jatropha curcas L. in semi-arid conditions of Botswana: applying the CROPWAT model, Agricultural Water Management, 225: 105754.

https://doi.org/10.1016/j.agwat.2019.105754

Munaiz E., Albrecht K., and Ordás B., 2021, Genetic diversity for dual use maize: grain and second-generation biofuel, Agronomy, 11(2): 230.

https://doi.org/10.3390/AGRONOMY11020230

Nimir N., and Guisheng Z., 2018, Photosynthesis and carbon metabolism. photosynthesis - from its evolution to future improvements in photosynthetic efficiency using nanomaterials.

https://doi.org/10.5772/INTECHOPEN.78031

Osman A., Mehta N., Elgarahy A., Al-Hinai A., Al-Muhtaseb A., and Rooney D., 2021, Conversion of biomass to biofuels and life cycle assessment: a review, Environmental Chemistry Letters, 19: 4075-4118.

https://doi.org/10.1007/s10311-021-01273-0

Paul M., Nuccio M., and Basu S., 2018, Are GM crops for yield and resilience possible? Trends in plant science, 23(1): 10-16.

https://doi.org/10.1016/j.tplants.2017.09.007

Peng L., Fu D., Chu H., Wang Z., and Qi H., 2019, Biofuel production from microalgae: a review, Environmental Chemistry Letters, 18: 285-297.

https://doi.org/10.1007/s10311-019-00939-0

Praveen K., Jha G., and Aditya K., 2021, Discerning sustainable interaction between agriculture and energy in India, Current Science.

https://doi.org/10.18520/cs/v120/i12/1833-1839

Robak K., and Balcerek M., 2018, Review of second generation bioethanol production from residual biomass, Food technology and biotechnology, 56(2): 174-187.

https://doi.org/10.17113/ftb.56.02.18.5428

Sameeroddin M., Deshmukh K., Viswa G., and Sattar M., 2021, Renewable energy: fuel from biomass, production of ethanol from various sustainable sources by fermentation process, Materials Today: Proceedings.

https://doi.org/10.1016/J.MATPR.2021.01.746

Schifter I., González U., Díaz L., Rodriguez R., Mejía-Centeno I., and González-Macías C., 2018, From actual ethanol contents in gasoline to mid-blends and E-85 in conventional technology vehicles. Emission control issues and consequences, Fuel, 219: 239-247.

https://doi.org/10.1016/J.FUEL.2018.01.118

Shrestha S. L., Allen F.L., Goddard K., Bhandari,H.S., and Bates G.E., 2023, Genetic variation for bioenergy traits within and among lowland switchgrass (Panicum virgatum L.) crosses, Biomass and Bioenergy, 175: 106878.

Sieradzka M., Gao N., Quan C., Mlonka-Mędrala A., and Magdziarz A., 2020, Biomass thermochemical conversion via pyrolysis with integrated CO2 capture, Energies, 13(5): 1050.

https://doi.org/10.3390/en13051050

Souza N., Fracarolli J., Junqueira T., Chagas M., Cardoso T., Watanabe M., Cavalett O., Filho S., Dale B., Bonomi A., and Cortez L., 2019, Sugarcane ethanol and beef cattle integration in Brazil, Biomass and Bioenergy, 120: 448-457.

https://doi.org/10.1016/J.BIOMBIOE.2018.12.012

Vergel-Ortega M., Valencia-Ochoa G., and Duarte-Forero J., 2021, Experimental study of emissions in single-cylinder diesel engine operating with diesel-biodiesel blends of palm oil-sunflower oil and ethanol, Case Studies in Thermal Engineering, 26: 101190.

https://doi.org/10.1016/j.csite.2021.101190

Yahia E., García-Solís P., and Celis M., 2019, Contribution of fruits and vegetables to human nutrition and health, Postharvest Physiology and Biochemistry of Fruits and Vegetables, 19-45.

https://doi.org/10.1016/B978-0-12-813278-4.00002-6

Yu S., and Tian L., 2018, Breeding major cereal grains through the lens of nutrition sensitivity, Molecular plant, 11(1): 23-30.

https://doi.org/10.1016/j.molp.2017.08.006

Zhang Y., Tan T., Wang J., and Zhang W., 2022, Recent development of key technologies in algae biofuels production, Bioresource Technology, 344: 126195.

https://doi.org/10.1016/j.biortech.2021.126195

Zhou Q., Le Q., Yang H., Gu H., Yang Y., Sonne C., Tabatabaei M., Lam S., Li C., Chen X., and Peng W., 2022, Sustainable conversion of agricultural biomass into renewable energy products: a discussion, BioResources, 17(2): 3489-3508.

https://doi.org/10.15376/biores.17.2.zhou