Monitoring degradation of restaurant wastewater by Lysinibacillus sphaericus C3-41

Abstract

This study investigates the biodegradation abilities of Lysinibacillus sphaericus C3-41 in restaurant wastewater. The extent of biodegradation was monitored using Fourier Transform Infrared Spectroscopy (FTIR) and Fatty Acid Methyl Ester (FAME) analysis. There was significant reduction in mineral content (p < 0.05) of the wastewater after 6 days incubation while the highest growth (1.4 OD600) and lipase production (50mMol/min) was observed on the 5th day. About 2.5% (v/v) oil concentration and pH 8 were found to be optimal conditions for growth and lipase production, while a temperature of 30 °C, and 1% ammonium phosphate and glucose were detected as optimum nitrogen and carbon sources respectively. FAME analyses revealed the presence of some fatty acids such as palmitic acid (11.56 ppm), caprylic (11.22 ppm), caproic (11.19 ppm), lauric acid (9.95 ppm), undecanoic (4.77 ppm) and cyclopropane fatty acid (CFA, 4.34 ppm) in the fresh domestic wastewater. After biodegradation, there was an increase in the concentration of capric (0.39 ppm), lauric (0.33 ppm), palmitoleic (0.78 ppm), trans13 octadecanoic (1.00 ppm) and cyclopropanoic (2.53 ppm) in L. sphaericus C3-41. Also, reduction in concentration of some fatty acids components in the wastewater probably eventually resulted in their bioaccumulation in the bacteria cell. FTIR spectra revealed the changes in functional groups qualitatively and quantitatively with evidence of wastewater biodegradation by L. sphaericus C3-41. The prominent –NH stretching bonds at 3740 cm−1 from the primary and secondary amines completely disappeared after the 6th day, indicating chemical reduction of –NH bonds leading to liberation of NH3(g). This study thus confirms the bioremediation potentials of L. sphaericus C3-41 for domestic and restaurant wastewater.