Optimization of L-asparaginase production using native soil-isolated Bacillus sp. and evaluation of its anticancer activity

Bacteria are one of the most important sources of L-asparaginase (ASNase) production which is used as an anticancer agent in the treatment of acute lymphoblastic leukemia worldwide. This study aimed to optimize the ASNase production by bacteria isolated from the soil in northern Iran, and to determine its anti-cancer activity. 

ASNase production by bacterial strains isolated from forest soil samples in Guilan Province, northern Iran was investigated. The optimized condition of enzyme production, kinetics, effect of activators and inhibitors and anticancer activity of the partially purified L-asparaginase against MCF-7 cell lines were studied.

A promising ASNase producing isolate, was identified by 16S rRNA gene sequencing as Bacillus sp. The glutaminase activity of the enzyme was found to be 5.9 times lower than its asparaginase activity and the enzyme showed affinity for L-asparagine with a Km value and Vmax of 0.055M and 35.71 µM/mL/min, respectively. The current ASNase enzyme was stable from pH 6.5 to 8.5 and stable up to 55°C. ASNase activity was not significantly affected by the presence of two metal ions Na+, K+; Mg2+ showed enhancement in enzyme activity, while Ca2+ decreased it. Anticancer activity of the purified L-asparaginase was detected against MCF-7 cell lines with IC50 of 21µg/ml.

The soil isolate Bacillus sp. was identified as a candidate for L-asparaginase production. The future prospect of this enzyme recommends its utility in pharmaceutical and food industry.