Isolation of asparaginase-producing microorganisms and evaluation of the enzymatic antitumor activity

Background L-asparaginase is an enzyme with very high biological activity owing to its activity on several tumor cells. It is mainly used to treat acute lymphoblastic leukemia. The complicated immunogenic adverse effects of present microbial sources present a need for switching to natural novel sources that have no immunogenic effect and better activity of L-asparaginase, so screening for other sources of L-asparaginase, like marine bacteria, may result in an enzyme having fewer adverse effects. Objective To screen and identify marine eco-friendly and potent L-asparaginase-producing bacteria, having a novel immunological property that possibly will avoid hypersensitivity. Materials and methods In the present study, bacterial strains were screened for extracellular L-asparaginase production from marine isolates, identified by 16 s rDNA technology, and L-asparaginase productivity was assessed using semiquantitative and quantitative enzymatic assays. The antiproliferative effect of the partially purified enzyme on different tumor human cell lines [HepG-2 (human hepatocellular carcinoma cell line), MCF-7 (breast cancer cell line), and PC-3 (prostate carcinoma cell line)] was assessed by the mitochondrial-dependent reduction of yellow MTT. Results and conclusion Bacillus safensis was established as the bacterial strain (Gene Bank accession number: MK541039). The extracellular enzyme-yielding capacity of the isolate B. safensis (518 IU/ml) was found to be 4.18 times higher than Bacillus pumilus (157.03 IU/ml) and higher than Bacillus circulans species (85 IU/ml). The marine isolate is environmentally friendly and can be used to produce significant quantities of extracellular L-asparaginase for the treatment of a variety of tumors and preparation of acrylamide-free fry food.