Studies on efficient production of a novel l-asparaginase by a newly isolated Pseudomonas resinovorans IGS-131 and its heterologous expression in Escherichia coli.

Abstract

In the current study, the production of novel glutaminase free l-asparaginase from a new microbial source (Pseudomonas resinovorans IGS-131) is reported. Optimization of l-asparaginase production using conventional and statistical optimization techniques resulted in an enzyme yield of 37.63IU/mL, which was 3.45-fold higher than the initial enzyme activity (i.e., 10.91IU/mL). l-Asparaginase production from P. resinovorans IGS-131 was successfully carried out at the bioreactor level and investigations on the effect of agitation rates showed a maximum asparaginase yield of 38.88IU/mL after 24h fermentation at 400rpm. The l-asparaginase gene from this source, showing 78% identity with a reported sequence in GenBank, was expressed in Escherichia coli rosetta DE3. The molecular weight of the recombinant protein was determined as 35.6kDa. Downstream processing of recombinant l-asparaginase resulted in a purified protein concentration of 62.53mg/L, which showed good free radical scavenging activity of 62%. The current findings provide promising results for a process of l-asparaginase production from P. resinovorans IGS-131. Furthermore, the recombinant production of this enzyme could help in avoiding the complexity of down streaming processes associated with the purification of this enzyme from wild-type organisms.