Comparison of the fates of the methyl carbons of m-cresol and p-cresol in methanogenic consortia

Abstract

The fates of the methyl carbons of 14C-methyl labeled m-cresol and p-cresol in methanogenic consortia were determined. The reduction of H14CO3- to 14CH4 by these consortia was also examined. Most (92%) of the methyl carbon of p-cresol was oxidized to 14CO2 (H14CO3-) accompanied by some reduction of H14CO3- to CH4 (2% of label). In contrast 87% of the methyl carbon of m-cresol was converted to CH4 and only 5% was recovered as CO2. No reduction of H14CO3- to 14CH4 was observed in m-cresol degrading consortia. Both consortia incorporated small percentages of the methyl label into cellular macromolecular material.