Optimization of L-asparaginase Production from a Lactobacillus sp. isolated from Traditional Dairy Products

Asparaginase catalyzes the deamination of asparagine into aspartate and ammonia. Currently, it is used as an important chemotherapeutic agent for the treatment of different cancers such as acute lymphoblastic leukemia, malignant diseases of the lymphoid system, and Non-Hodgkin Lymphoma (NHL). Asparaginase is a useful enzyme for the food industry due to its potential to prevent acrylamide formation and to maintain the quality of the food. Probiotic products contain useful bacteria that have beneficial effects on health. The most important biological properties of probiotics include the elimination of mutagenic and carcinogenic agents. There are many microorganisms that could potentially function as the probiotic, the most common of which are Lactobacillus and Bifidobacterium species. The aim of this study was to optimize the production of L-asparaginase from isolated Lactobacillus sp. from the traditional whey of Maragheh.

The isolate was investigated through microbial and biochemical tests including gram staining, catalase and oxidase activity, fermentation of carbohydrates, and acid and bile salts resistance. Asparaginase production was evaluated by qualitative and quantitative methods, rapid plate assay, and Imada method, respectively. Asparaginase production was optimized by the Response Surface Method (RSM).

According to the RSM results, the highest activity of asparaginase was 131 U/mg, which was 11% more than the non-optimized condition. The optimized parameters composed of asparagine (1.75 %), glucose (2 %), and yeast extract (1.25 %). Furthermore, the total protein content and biomass of the optimized medium were 0.893 mg/ml and 0.345 g, respectively. 

Discussion and conclusion:

This isolated lactobacilli strain may be considered as a significant source for the production of the enzyme with the pharmacological value of asparaginase.