Genomic Analysis and Identification of Catabolic Pathways for Aromatic Compounds in Corynebacterium glutamicum

Abstract

The catabolism of aromatic compounds in Corynebacterium glutamicum was investigated by genome data mining and by experimental analysis. Results indicated that C. glutamicum assimilated different aromatic compounds such as phenol, p-cresol, benzoate, 4-hydroxybenzoate, vanillate, vanillin, resorcinol, 3,5-dihydroxytoluene and 2,4-dihydroxybenzoate. Genome data indicated, and enzyme assays confirmed; the existence of multiple ring-cleavage pathways for the catabolism of central aromatic intermediates; the protocatechuate and catechol branches of the β-ketoadipate pathway, two similar hydroxyquinol pathways and the gentisate pathway. Two putative hydroxyquinol 1,2-dioxygenase genes (ncg11113 and ncg12951) were cloned and functionally identified in Escherichia coli. The genes encoding enzymes for the conversion of phenol, benzoate, 3-hydroxybenzoate, 4-hydroxybenzoate and vanillate in the central β-ketoadipate pathways were mapped on the chromosome of C. glutamicum. A unique 30-kb (approximately 1% of the entire genome) catabolic island that channels the degradation of various aromatic compounds was mapped to position 2525-2555 kb of the genome. The global analysis and characterization of aromatic degradation pathways provided new insights into the metabolic ability of C. glutamicum in addition to its well-known ability to produce various amino acids and vitamins. © 2005, Japanese Society of Microbial Ecology · The Japanese Society of Soil Microbiology. All rights reserved.