Valorization of volatile fatty acids derived from low-cost organic waste for lipogenesis in oleaginous microorganisms-A review

Abstract To meet environmental sustainability goals, microbial oils have been suggested as an alternative to petroleum-based products. At present, microbial fermentation for oil production relies on sugar-based feedstocks. However, these substrates are costly, in limited supply, and present an elevated risk of contamination. Volatile fatty acids, which are generated as intermediates during anaerobic digestion of organic waste, could replace conventional sugar sources for microbial oil production. They comprise short-chain (C2 to C6) organic acids and are employed as building blocks in the chemical industry. The present review discusses the use of oleaginous microorganisms for the production of biofuels and added-value products starting from volatile fatty acids as feedstocks. The review describes the metabolic pathways enabling lipogenesis from volatile fatty acids, and focuses on strategies to enhance lipid accumulation in oleaginous microorganisms by tuning the ratios of volatile fatty acids generated via anaerobic fermentation.