Degradation pathway of persistent branched fatty acids in natural anaerobic ecosystem

Branched fatty acids (BAFs) in industrial effluents are often persistent in biological wastewater treatment systems and end up as organic contaminants in the water environment. In this study, degradation of eight characteristic BAFs in a natural anaerobic ecosystem of an eutrophic river sediment was studied in vitro by enrichment culture techniques. The anaerobic consortium, comprising of BFA-degrading and methane-producing genera, degraded BFAs with a tertiary carbon through beta-oxidation followed by methanogenesis mechanisms. The consortium could not degrade BFAs with a quaternary carbon. The degree of branching at the alpha or beta position along the carbon chain interfered with the beta-oxidation mechanisms, and hence affected the degradability of the compound.