Isolation and Identification of Benzoate Degrading Bacteria from Food Industry Effluent

Sodium benzoate, the sodium salt of benzoic acid, is the first accepted and one of the widely used chemical preservatives in the food, cosmetic and, beverage industries. In recent past, soaring demand of packaged food resulted in increased industrialization and intensified use of chemical preservatives. The residual remains of these industries are discharged into their wastewater treatment plants (WWTP) and effluent treatment plants (ETP) thus concentrating the chemical preservatives in these treatment plants. This causes harmful effects on the growth of indigenous microbes in treatment plants and reduces the effectiveness of biological processes in secondary wastewater treatment. Therefore, it is necessary to degrade preservatives like sodium benzoate in the WWTP/ETP of industries. The ETP samples were collected from food processing industry for the isolation of sodium benzoate degrading aerobic bacteria. The microscopic analysis of the isolate with maximum ability to grow at a very high concentration of sodium benzoate (10 000 mg/L) showed it to be Gram-positive, endospore forming bacteria. The molecular characterization was done using 16S rDNA sequencing with universal primers and the isolate was identified as Bacillus subtilis DSSK1. The sequence was submitted to NCBI GenBank with accession number MT704505. The isolate was able to utilize sodium benzoate as the sole carbon and energy source. It was able to degrade 76% of sodium benzoate (10 000 mg/L) in 72 h. It was also able to produce hydrolytic and oxidative enzymes (cellulase, amylase, pectinase and laccase) which can help it to better survive in the food industry effluent rich in cellulose, starch, pectin, and lignin thus making it a promising candidate for industrial effluent treatment rich in benzoate.