Degradation of long-chain fatty acids by sulfate-reducing and methanogenic communities

Abstract

Lipids and long chain fatty acids (LCFA) are energy-rich compounds that support the growth of microorganisms that thrive in environments with a low redox potential. This chapter describes the properties LCFA-degrading sulfate-reducing bacteria and LCFA-degrading methanogenic communities. The methanogenic conversion of LCFA requires syntrophic communities of acetogenic bacteria and methanogenic archaea. In this syntrophic cooperation, interspecies hydrogen transfer plays a key role. The understanding of the microbial interactions involved in LCFA degradation is essential to optimize the methane formation from LCFAcontaining waste streams in bioereactors. Sulfate-reducing and methanogenic communities degrade LCFA by b-oxidation, but the differences and similarities between the degradation of saturated and unsaturated LCFA are not yet fully understood. Generally, bacteria that degrade unsaturated fatty acids degrade saturated fatty acids also, but the opposite does not always seem to be the case