Mitigating biomass recalcitrance for plant‐based bioenergy production

• Published in: Modern Agriculture 2023-09, Vol.1 (2), p.122-141
• Main Authors: Ninkuu, Vincent, Liu, Zhixin, Zhou, Yaping, Guo, Enzhi, Song, Xiao, Gao, Peibo, Xie, Yajia, Sun, Xuwu
• Format: Article
• Language: English
• Subjects: Abiotic stress; Alternative energy sources; Alternative fuels; Biodegradation; Biodiesel fuels; bioenergy; Biofuels; Biomass; Biomass burning; Biosynthesis; Carbon dioxide; Cellulose; Climate change; Composition; Corn; Crop production; Flowers & plants; Fossil fuels; Fuel combustion; Genetic transformation; Global warming; Grasses; Greenhouse effect; Greenhouse gases; Hazardous materials; hemicellulose; Lignin; Lignocellulose; Permeability; Pollution levels; Polymers; Proteins; Raw materials; recalcitrance; Renewable energy; Reviews; Saccharification; Sorghum
• ISSN: 2751-4102; 2751-4102
• DOI: 10.1002/moda.21

The emission of greenhouse gases, particularly carbon dioxide, predominantly from fossil fuel combustion has received critical warnings several times as their levels exceed the tolerable limits in view of global warming. This calls for a paradigm shift from a fossil fuel‐based source to a less hazardous bioenergy source. Plant feedstock is an attractive source of raw materials for bioenergy production; however, chemical or enzymatic digestion of the feedstock is expensive owing to the supramolecular lignocellulosic barrier, indicating the need for better alternatives. Several attempts have been made towards reducing the biomass recalcitrance of straw using genetic transformations. We present a review highlighting potential plant candidates for bioenergy production, the lignocellulose composition of the feedstock, how the composition can impede enzymatic degradation, the regulation of lignocellulose polymer biosynthesis, and the influence of genetic transformation on biomass saccharification. Moreover, the review also discusses conflicting research interests in biomass recalcitrance and suggests a common ground. The review findings suggest that bioenergy production from crop straws will drastically reduce over‐dependence on fossil fuels and consequently pollution levels. Sustainable mitigation of biomass recalcitrance enhances plant‐based bioenergy production. (a) Recent trends in plant‐based bioenergy production aim to genetically modify lignocellulosic feedstock to improve biomass saccharification. This can be achieved by altering gene regulations that impose biomass recalcitrance, such as lignin and cellulose. For example, mutant lines of CESA4 and ‐7 inhibit cellulose production, whereas MYB4a in switch grasses modulates the expression of lignin biosynthetic genes to inhibit lignin production. Additionally, MYB167 negatively affects xylan synthesis without impacting lignin content. (b) Genetic transformations based on gene functions can reduce biomass recalcitrance in lignocellulosic feedstock. (c) Highly degradable feedstock facilitates bioenergy production with little or no enzymatic digestion, reducing production costs. (d) Green energy produced sustainably powers automobiles and homes without contributing to greenhouse gases.