Isolation of a benzoate-utilizing Pseudomonas strain from soil and production of catechol from benzoate by transpositional mutants

Pseudomonas sp. Ba-0511 was isolated from soil by enrichment cultivation on a medium containing 6 mg/ml of sodium benzoate. The bacterium could grow on a medium containing 20 mg/ml of sodium benzoate by a successive enrichment culture. One hundred and twelve transpositional mutants of the bacterium produced catechol from benzoate and accumulated it outside of the cells. Among the mutants, strain BA+63 produced a maximal amount of catechol (2.3 mg/ml) from 6 mg/ml of sodium benzoate after growing for 10.5 h. The conversion rate of benzoate to catechol was 50% on a molar basis. The catechol production by the resting cells increased in the presence of glycerol, and the maximal amount of catechol produced from 6 mg/ml of sodium benzoate reached 3.3 mg/ml at the conversion rate of 72% after 5 h of incubation. The resting cells converted m-methylbenzoic acid to 3- and 4-methylcatechol and m-chlorobenzoic acid to 3- and 4-chlorocatechol.