Exploitation of Agricultural Waste as Sole Substrate for Production of Bacterial l-Glutaminase Under Submerged Fermentation and the Proficient Application of Fermented Hydrolysate as Growth Promoting Agent for Probiotic Organisms

Abstract

Microbial l-glutaminase has diverse applications, ranging from food flavouring agent to treatment of cancer. Extracellular l-glutaminase producing one soil bacterium was characterized as Acinetobacter calcoaceticus PJB1 and was grown under submerged fermentation using sugarcane bagasse as sole supporting substrate. The optimum l-glutaminase production was achieved at initial medium pH of 10.0, incubation temperature at 35 °C, inoculums concentration of 1.5% (v/v) and at 72 h. Further improvement of the enzyme production was carried out by statistical optimization procedure using response surface methodology as a result of which enzyme production was enhanced to 47.95 U/ml (2.38-fold improvement). The enzymatic degradation pattern of sugarcane bagasse was appraised using Fourier transform infrared spectroscopy and light microscope. The fermented hydrolysate was proved to be a very effective growth inducer of probiotic organism as reflected by the higher specific growth rate, volumetric growth rate and overall yield of Lactobacillus sp. and Bifidobacterium sp. This study highlights the cost effective production of l-glutaminase and simultaneous utilization of fermented waste product as growth supporting agent for health beneficial probiotic organisms.