A Biochemistry Teaching Activity to Modify the Theoretical Methane Yield Formula in Anaerobic Digestion

Abstract Biochemistry not only plays an important role in daily life and industrial practice but also is a core foundational course in universities worldwide. Anaerobic digestion (AD) is a representative catabolic reaction in biochemistry that can promote carbon circulation and maintain ecological balance, but has long been neglected in biochemistry courses. We incorporated AD theories and practices in the course of biochemistry, and Boyle’s formula was used to estimate the theoretical methane yield (TMY) of organic substrates in AD, to evaluate their biodegradability (Bd). However, students were unaware that lignin could not be degraded by AD and used Boyle’s formula to calculate the overestimated TMY of lignocellulosic wastes. To solve these problems, we designed a teaching activity to explain the properties of lignin and guide students to modify the original Boyle’s formula through two methods, to eliminate the interference of lignin. This teaching activity not only helped students learn the non-biodegradability of lignin in anaerobic environment and how to eliminate the influence of lignin on Boyle’s formula, but also provided a more reliable tool for estimating the TMY and Bd in future applications. This teaching activity can provide a reference for teachers who taught biochemistry course in related majors, reflecting its multidisciplinary value.