Biodegradation of p-cresol by Serratia marcescens strain HL 1 in batch system: Process optimization, growth kinetic study, phytotoxicity and chlorophyll assessment

Abstract

The batch experiment was performed for biodegradation of p-cresol from synthetic wastewater using an isolated gram-negative bacterial strain (i.e., Serratia marcescens strain HL 1 (EU371058)). Biodegradation rate affecting parameters such as pH (5.0–10), p-cresol concentration (20–100 mg·L−1), and retention time (24–72 h) were optimized. The maximum degradation (86.32 %) of p-cresol was obtained at an initial concentration of 60 mg·L−1, pH of 7.5, and retention time of 48 h. Based on Haldane model, maximum specific growth (μmax) of the cell was 0.2 h−1, and inhabitation constant (KI) of substrate was 76 mg·L−1. FTIR was used to identify the available functional group in biodegraded p-cresol solution. Conclusively, it was observed that a first-order model could accurately predict reaction kinetics. The rate constant values for the first-order was 0.002 L g VSS−1 h−1. Phytotoxicity and chlorophyll were also investigated.