Anaerobic digestion as a laboratory experiment for undergraduate biochemistry courses

Compared to aerobic catabolism, the theories and experiments of anaerobic catabolism are not covered in depth in biochemistry education curricula. Anaerobic digestion (AD) is a feasible method for converting common organic compounds to renewable energy-methane that has drawn a great deal of attention in practical applications. In this study, we designed an AD laboratory experiment for use in undergraduate biochemistry courses to supplement the knowledge of metabolic networks in biochemistry and extend the information presented in biochemistry textbooks. In this laboratory experiment, students explored the methane production performance of wheat straw (WS; a representative and commonly available agricultural waste) and mastered a reasonable method for utilizing this new biochemical reaction to convert organic wastes from renewable resources to methane. Basic experimental procedures, such as a biochemical methane potential (BMP) assay, data analysis, and graphic presentations were organized to provide students with abundant hands-on experience. Furthermore, calculations of significant parameters, such as total solids (TS), volatile solids (VS), experimental methane yield (EMY), maximum theoretical methane production (MMP), and biodegradability (B_D ), were also performed. From this AD experiment, students learned not only a new series of biochemical reactions but also a novel strategy to achieve cleaner methane production from organic wastes, exhibiting a positive impact for students' learning in biochemistry course.