Identification of accumulated intermediates frIdentification of accumulated intermediates from the degradation of acenaphthylene by Rhizobium sp. CU-A1 transposon mutantsom the degradation of acenaphthylene by Rhizobium sp. CU-A1 transposon mutants.
Abstract:
Eighteen transposon mutants of Rhizobium sp. CU-A1 defective in acenaphthylene degradation could be classified into 6 groups by the growth and intermediate accumulation patterns when grown in the presence of acenaphthylene as a sole carbon source. The mutant strains A53, B1 and B5 belonging to groups 5, 2 and 3, respectively, were selected for further purification of the accumulated intermediates as they showed different types of intermediates from those found in the wild type and also in high concentration. These intermediates were isolated and purified by preparative thin-layer chromatography and silica gel column chromatography, then identified by mass spectrometry and nuclear magnetic resonance to be 2,5-dihydroxybenzoic acid (gentisic acid) from strain A53, acenaphthenequinone from strain B1 and naphthalene-1,8-dicarboxylic acid from strain B5. Therefore, the pathway of acenaphthylene degradation in Rhizobium sp. CU-A1 is tentatively proposed as follow: acenaphthylene is metabolized to acenaphthenequinone, naphthalene-1,8-dicarboxylic acid and 2,5-dihydroxybenzoic acid, respectively.