Involvement of poly(3‐hydroxybutyrate) synthesis in catabolite repression of tetralin biodegradation genes in Sphingomonas macrogolitabida strain TFA

Summary The tetralin biodegradation genes of Sphingomonas macrogolitabida strain TFA are repressed by catabolite. Insertion mutants in which thn genes are transcribed in the presence of a preferential carbon source and tetralin, bear the insertion in phaC, encoding a poly(3-hydroxybutyrate) (PHB) synthase, a key enzyme in PHB synthesis. Mutant complementation with phaC genes from either Ralstonia euthropha or TFA restored PHB accumulation and the wild-type regulatory pattern of thn genes, thus indicating that this accumulation is a signal for carbon sufficient conditions that prevents expression of thn catabolic genes in this α-proteobacteria.