Harnessing salt stress to drive the efficient and inexpensive bioproduction of a valuable thermotolerant biocatalyst (Mn-catalase) from cyanobacterial biomass

Abstract

The catalase enzyme, widely used in industries (food, textiles etc.), is mostly procured from animal or fungal sources. Here, we have utilized the cyanobacterium Anabaena for the green synthesis of a thermostable Mn-catalase, KatB. Ability of Anabaena to biosynthesize high levels of KatB in response to salt (NaCl) stress was exploited for this purpose. Notably, this method obviated the need of any genetic manipulation, thus eliminating the risks associated with recombinant organisms. The robust nature of the KatB protein made it amenable for purification via simple eco-friendly downstream processing steps that included heat-treatment and ammonium sulfate precipitation. Interestingly, KatB acquired from salt-treated Anabaena was more active and less prone to chemical denaturation than KatB isolated from Anabaena/E. coli after over-production using expression vectors. In this unique study, the adaptive ability of Anabaena has been channelized to convert this photosynthetic organism into a cost-effective bioresource for protein production and purification.