Production, optimization, purification, characterization, and anti-cancer application of extracellular L-glutaminase produced from the marine bacterial isolate

Abstract

L-glutaminase from bacterial sources has been proven to be effective and economical agents in cancer therapy, food industry and high-value chemicals like threonine. In the present study, a newly isolated bacterial strain was potentially producing extracellular L-glutaminase, it identified as <i>Bacillus subtilis</i> OHEM11 (MK389501) using the <i>16S rRNA</i> gene. L-glutaminase production optimized and the optimum factors for production under submerged fermentation were at pH 6.5-7.0 and 35 °C after 28 hr using rhamnose and glutamine as carbon and nitrogen sources, respectively, while bagasse was the best inducer for the production under solid-state fermentation. Ethanol precipitation and ion-exchange chromatography using QFF are the purification steps. L-glutaminase was purified to 2-fold with specific activity 89.78 U/mg and its molecular weight about 54.8 kDa with the alkaline property of the enzyme makes it clear having carcinostatic property; maximum enzyme activity at pH 8.2 and 40 °C and retained about 90% activity for 1 hr. The cytotoxicity effect of L-glutaminase indicated a significant safety on Vero cells with high anticancer activity against NFS-60, HepG-2, and MCF-7 cancer cell lines. The outcomes demonstrated that L-glutaminase could be applied in many biotechnological applications such as pharmaceutical and food processing.