Production of <em>p</em>-hydroxybenzoic acid and caffeic acid from <em>p</em>-coumaric acid using <em>Streptomyces caeruleus</em> MTCC 6638.

Abstract

<em>Streptomyces caeruleus</em> MTCC 6638 was analyzed for its capability to biotransform <em>p</em>-coumaric acid and co-production of <em>p-</em>hydroxybenzoic acid and caffeic acid was observed. It was found that 5 mM concentration of the substrate was optimum for production of both <em>p-</em>hydroxybenzoic acid and caffeic acid. The biotransformed products were identified by thin layer chromatography (TLC) and quantified by high performance liquid chromatography (HPLC). A maximum amount of 41.8 mg/l of <em>p-</em>hydroxybenzoic acid and 22.8 mg/l of caffeic acid was produced. Minimal medium supplemented with various nitrogen sources had little effect on product formation. Other than ammonium nitrate, potassium nitrate could produce a maximum of 43 mg/l of <em>p</em>-hydroxybenzoic acid and presence of ammonium nitrate and ammonium sulphate could produce a maximum of 22.8 and 22.4 mg/l of caffeic acid, respectively. Fresh Murashige and Skoog (MS) and the spent MS media were also used for biotransformation and it was observed that MS spent medium had little effect on the production (6.6 mg/l of <em>p</em>-hydroxybenzoic acid) in presence of kinetin. Therefore, <em>Streptomyces caeruleus</em> can be exploited for production of value added compounds.