Acetoclastic

Acetoclastic is an adjective used in biology and biochemistry to describe reactions or organisms that cleave acetate. In microbial metabolism, acetoclastic organisms convert acetate into other products, most notably methane and carbon dioxide during acetoclastic methanogenesis.

In acetoclastic methanogenesis, acetate is activated to acetyl-CoA, then cleaved by the CODH/ACS complex into a methyl group that becomes methane and a carbonyl that forms CO2. The net reaction is CH3COO− + H2O → CH4 + HCO3−. Key acetoclastic methanogens include the archaeal genera Methanosarcina and Methanosaeta (also called Methanothrix); Methanosaeta is adapted to very low acetate concentrations, while Methanosarcina can utilize higher acetate levels and a broader substrate range.

Acetoclastic metabolism is a major pathway of methane production in anaerobic digestion and in natural environments such as wetlands. It competes with hydrogenotrophic methanogenesis, which reduces CO2 with hydrogen to methane. Understanding acetoclastic pathways informs biogas optimization and carbon cycling, as environmental factors such as pH and ammonia can influence acetoclastic activity.

The term is primarily used in methanogenesis research, describing acetate-cleaving processes in acetoclastic organisms, though acetoclastic concepts can appear in other biochemical contexts where acetate substrates are cleaved.