Journal of Energy Bioscience 2024, Vol.15, No.6, 349-357 http://bioscipublisher.com/index.php/jeb 354 6 Environmental and Economic Impacts 6.1 Reduction in greenhouse gas emissions from bioethanol production Producing bioethanol from high-fiber maize can significantly reduce greenhouse gas (GHG) emissions compared to traditional fossil fuels, with maize ethanol reducing GHG emissions by approximately 12% to 20% compared to gasoline. Studies have shown that maize ethanol, especially when produced through sustainable practices such as double cropping with soybeans, can significantly reduce GHG emissions (9.3 to 13.2 million tons CO2). For example, in Brazil, maize ethanol as a second crop to soybeans was found to reduce GHG emissions compared to gasoline and reduced land use emissions, highlighting the environmental benefits of this approach (Moreira et al., 2020). The use of biochar in maize cultivation has been shown to reduce nitrous oxide (N2O) emissions, further reducing overall GHG emissions (Zhang et al., 2019). 6.2 Economic benefits for farmers cultivating high-fiber maize The production of cellulosic ethanol from crop straw has increased farmers' enthusiasm for growing crops and their income from growing crops. Intensifying maize production, especially through sustainable practices, can increase yields and economic returns. One ton of cellulosic ethanol consumes five tons of straw, and each ton of straw can increase farmers' income by 300 yuan in the "collection, storage and transportation" stage. For example, small farmers in the North China Plain who adopted high-yield methods increased maize yields by 34.9% and economic benefits by 14.4% (Ren et al., 2020). In addition, the production of hybrid maize seeds in Northwest China showed that optimizing nitrogen fertilizer inputs and irrigation can reduce costs and increase yields, thereby improving the economic feasibility of maize cultivation (Liu et al., 2021a). These economic benefits encourage farmers to adopt sustainable practices and contribute to the bioethanol supply chain, optimize farmland management measures, and enable China to achieve intensive but sustainable agricultural production at a lower environmental cost. 6.3 Addressing sustainability concerns in bioethanol production Sustainability is a key issue in bioethanol production, and the development of high-fiber maize can help achieve green, low-carbon sustainable development goals. Sustainable crop management practices, such as balanced fertilization and the use of biochar, can improve soil quality, promote maize production, and protect the environment (reduce greenhouse gas emissions) (Agegnehu et al., 2016). Optimizing the rotation mechanism of maize and soybeans can ensure sufficient feed while reducing nitrogen and carbon footprints. The CDSI of the bioethanol scenario has a strong carbon emission reduction capacity and contributes to more sustainable agricultural practices (Liu et al., 2021b). Using perennial biomass crops such as Silphium perfoliatum as an alternative to maize can also provide environmental benefits by reducing greenhouse gas emissions in the soil and providing multiple ecosystem services (Kemmann et al., 2021). Together, these strategies help address the sustainability issues associated with bioethanol production, making it a more viable and environmentally friendly alternative to fossil fuels. 7 Challenges and Limitations 7.1 Breeding trade-offs between high fiber and grain quality Breeding high-fiber corn for increased bioethanol production often involves a trade-off with grain quality. The increased ethanol yield of high-fiber corn comes at a cost, often at the expense of lower grain quality and grain yield. For example, European landraces that exhibit fiber traits favorable for biofuels tend to have lower harvest indices compared to hybrids, suggesting that grain yield may suffer (Munaiz et al., 2021). There are exceptions, however, and the genetic diversity exhibited by dual-purpose corn (grain and biofuel) suggests that some types can sacrifice grain yield for fiber traits, so a balance needs to be maintained in breeding programs. 7.2 Economic and logistical barriers to adoption of high-fiber maize There are significant economic and logistical challenges to adopting high-fiber maize for bioethanol production. The costs of developing and deploying new maize varieties with higher fiber content can be prohibitive, especially in developing regions with limited resources (Tandzi et al., 2017). The infrastructure required to process
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