1.5.1. Biochemical Conversion

Today, the biochemical conversion of agro-wastes into energy is a promising and emerging field of technology for sustainable development. Depending on the type and the nature of waste, different microbial consortia can play a crucial part in the conversion processes of such waste for energy generation. Two important processes, i.e., anaerobic digestion (AD) and fermentation, are coupled with biochemical conversion techniques.

AD is usually carried out in an oxygen-free environment where microorganisms help degrade or break down organic waste products into bioenergy. The four (4) main important stages in AD are known. These are hydrolysis, acidogenesis, acetogenesis, and methanogenesis. Each of the stages above is facilitated by different microbial populations that help convert one complex organic material to another. Most microorganisms associated with agro-waste biodegradation in AD processes include *Pseudomonas*, *Bacillus*, *Streptococcus*, *Clostridium*, *Methanococcus*, and *Methanobacteria* spp. These are mostly employed when handling waste with a high moisture content of about 80–90%. Equation (1) summarizes the stoichiometric relationship between agro-waste biodegradation by microorganisms in AD for biogas production, a renewable energy source.
