Screening of benzoic acid biodegradation strains

Three strains BQ, BJ, and BS utilizing benzoic acid as the sole carbon source were achieved from Yichang City, Hubei Province, China, through selective enrichment and domestication. Both BQ and BJ were primarily identified as Acinetobacter . spp while BS was Geotrichum . spp. After three domestications, the removal rates of BQ, BJ, and BS to chemical oxygen demand (COD) value of benzoic acid were 62.41%, 94.44%, and 43.34%, respectively. The strains were mixed cultured, and the degradation rates of strains to benzoic acid at different temperature, pH and benzoic acid concentration were determined. The results show that the optimum degradation conditions about strains were pH 7.0, temperature 30 °C, and aerobic with 1 500 mg/L of concentration of benzoic acid. In this condition, the COD removal rate of strains to benzoic acid reached 84.93%.