Immobilization and biochemical characterization of purified L-Asparaginase produced by Brevibacillus borstelensis ML12

Abstract

Purified L-Asparaginase from Brevibacillus borstelensis ML12 was immobilized, and sequentially studied for biochemical characterization and thermodynamic feasibility. Immobilization has long been used as a way to enhance enzyme stability, facilitate recovery, and multiple re-uses in industries. It is preferable to utilize natural nontoxic carriers and crosslinking agents to immobilize enzymes. L-Asparaginase is an important industrial enzyme due to its significant role in the pharmaceutical and food sectors. In this study, immobilization of purified L-Asparaginase from a novel bacterium Brevibacillus borstelensis ML12 was performed using different carrier matrices and concentration of the suitable matrix was varied to obtain maximum enzyme production. Biochemical parameters like effect of pH, temperature, surfactants, organic reagents, bile salt were also studied. Arrhenius plot and thermal stability of immobilized enzyme were obtained from thermodynamic studies. ΔH, ΔG and ΔS values were also determined. Operational and storage stability studies revealed that the enzyme was able to retain 80% of its activity after 3 cycles and relative activity falls by 45% after 48 hours under refrigerated conditions and by 50% at normal room temperature. Vmax and KM values were calculated by using Lineweaver-Burk plot and the values came out to be 121.654 µmole ml-1 min-1 and 0.310 mM respectively.