Carbon tetrachloride product shift in a methanogenic, iron-containing system

摘要

Transformation of carbon tetrachloride (CT) by Methanosarcina thermophila can be influenced by the presence of elemental iron (Fe~0). The transformation of CT by M.thermophila grown in the presence and absence of Fe~0 (P and A, respectively) was investigated using ~(14)C-CT. In both P and A treatments, the main degradation products were chloroform (CF) and CO_2. However, the P treatment produced greater amounts of CF, but degraded it at a higher rate than the A treatment. The P treatment also produced less ~(14)CO_2 than the A treatment. The results of ~(14)C-CT degradation experiments using the filtered culture supernatant from M. thermophila cultures grown with and without Fe~0 parallel those from the organism-containing systems, with the exception that CO is generated as an intermediate transformation product. The greater amounts of CF and the lesser amounts of CO and CO_2 produced by systems pre-exposed to Fe~0 suggest that Fe~0 creates conditions that lead to more hydrogenolysis of CT than occurs in systems without pre-exposure to Fe~0.