Biotechnology

Biography

Biography: Sudipta Dey

Abstract

Phenolic compounds including cresols and resorcinol are found to coexist in industrial effluent, especially in petrochemical, steel-plant, coke-oven wastewater. An indigenous mixed microbial culture collected from effluent treatment plant of a coke oven industry was used to biodegrade synthetic wastewater containing bi-substrate mixture of resorcinol and m-cresol, under aerobic condition in batch reactor system. The effect of individual substrate concentrations and their interaction on the rate of phenolics biodegradation were also determined. The resorcinol and m-cresol as bi-substrates were completely utilized after 18 hours when the solutes were present at low concentrations of 50 mg/L each. But the culture took total 74 hours to completely biodegrade higher concentrations i.e 400 mg/L of each substrate. Both substrates were degraded simultaneously, but preferential uptake of resorcinol over m-cresol was observed. Both specific growth rate of the culture and the specific substrate degradation rate descended to lower value in presence of dual phenolic substrates compared to their presence as single substrate, showing inhibition and interaction between the substrates. A 22 full factorial design with the two substrates at two different levels of initial concentration (high and low as 50 mg/L and 400 mg/L, respectively) was explored to design the biodegradation experiments and interactions. SUM kinetic model was fitted to experimental data by MATLAB 7.1© and used to evaluate kinetic parameters including interaction coefficients like qmax1, qmax2, Ks1, Ks2, I21, I12, Ki1, Ki2. From the interaction parameters obtained from this model, it was found that resorcinol inhibited the specific m-cresol degradation rate to a higher extent than inhibition caused by m-cresol on resorcinol degradation (I 21 =0.112, I 12 =0.216, RMSE =0.0111).