Multiple forms of O-methyltransferase involved in the microbial conversion of abietic acid into methyl abietate by Mycobacterium sp.

Six out of seven tested strains of mycobacteria transformed abietic acid to methyl abietate in shake culture. The conversion carried out by Mycobacterium sp. MB 3683 was induced by the substrate and stimulated by methionine. Fractionation of the cell extract of Mycobacterium sp. MB 3683 on DEAE cellulose, Ultrogel AcA 44 and MONO Q resulted in the separation of three distinct methyltransferase activities which could also esterify palmitic acid. The separated forms of the methyltransferase exhibited different activities towards these two substrates.

Novel metabolite structures from biotransformation of a sesquiterpenoid ketone by selected fungal strains.

The sesquiterpenoid ketone, 1,4,4-trimethyltricyclo[5.4.0.0(3.5)]undec-7-en-9-one (1), was subjected to microbial transformation by six fungal strains: Aspergillus niger ATCC 9142, Aspergillus ochraceus DSM 824, Beauveria bassiana ATCC 7159, Cunninghamella echinulata ATCC 9244, Rhizopus arrhizus ATCC 11.145, and Absidia blakesleeana ATCC 10.148. Four main metabolites were formed from 1: 10(R)- and 10(S)-hydroxy-1,4,4-trimethyltricyclo-[5.4.0.0(3.5)]undec-7- en- 9-one (2 and 3, respectively), besides 4(R)- and 4(S)-(hydroxymethyl)-1,4-dimethyltricyclo[5.4.0.0(3.5)]undec -7-en-9-one (4 and 5, respectively). Compounds 2-5 were isolated with varying percentages from the respective transformations, and their structures established unequivocally by a combination of spectroscopic methods. Metabolites 2 and 3 are products of hydroxylation at C-10, in either R- or S-position; in 4 and 5, one geminal CH3 group each on the cyclopropane ring has been transformed into a CH2OH function.