Enhancing methane production in two-phase anaerobic digestion of perishable organic waste: Mini-review on acidogenic fermentation pathways and regulatory strategies

Two-phase anaerobic digestion is a highly effective approach for efficient reduction and resource recovery of perishable organic waste. Within this technological framework, organic wastes undergo multiple metabolic pathways during the acidogenic phase, which is classified into ethanol, butyrate, propionate, lactate, and mixed acid fermentation depending on the acidification end products. The nature of these acidification products critically influences the performance of the subsequent methanogenic phase. Strategic regulation of operational parameters during the acidogenic phase fosters the enrichment of specific microbial communities and establishment of dominant consortia, which enable the production of the targeted acidification end-products. This review provides a comprehensive analysis of the metabolic characteristics and regulatory strategies associated with various acidogenic fermentation types and methanogenic properties of different acidification products. The findings presented here are crucial for enhancing the stability and methanogenic efficiency of anaerobic digestion systems that process perishable organic waste.