Facile generation of a biotechnologically-relevant catalase showcases the efficacy of a blue-green algal biomass as a suitable bioresource for protein overproduction.

•Cyanobacterium Anabaena bioengineered to produce the thermostable catalase, KatB.•Considerable production of KatB observed with a light-based promoter.•KatB was easily purified from Anabaena by heat-treatment & (NH4)2SO4 precipitation.•KatB purified from Anabaena was more active than the E. coli-purified KatB protein.•Unlike heme-catalase, KatB was functional at high temperatures and pH.