Enzymatic exploration of catalase from a nanoparticle producing and biodecolorizing algae Shewanella xiamenensis BC01

• Shewanella xiamenensis (SXM) produce nanoparticles under aerobic condition.
• This is the first attempt to explore seven oxidoreductases from SXM.
• Catalase was confirmed by zymographic and proteomics analyses.
• The highest catalase activity is 2967.2 U/mg at 65 °C, pH 4.0, 128.7 mM of H2O2.
• SXM would apply in bioremediation and microbe fuel cells with regard to catalase.

Shewanella xiamenensis (SXM) was found to produce nanoparticles (NPs) under aerobic condition. The oxidoreductase enzymatic activities including of catalase, manganese peroxidase, laccase, NADH dehydrogenase, flavin reductase, azoreductase and Fe reductase are first investigated. Catalase showed the greatest enzymatic activity among all oxidoreductases in SXM, which with strong activities in multiple substrates of ABTS, guaiacol and 2,6-DMP. The optimum temperature, pH, concentrations of H2O2 and 2,6-DMP for this enzyme were found to be 65 °C, pH 4.0, 128.7 mM and 10 mM, respectively. Finally, from the kinetic parameters and structure simulation of catalase, implied that SXM would potentially apply in bioremediation, microbe fuel cells (MFCs) and nano-biotechnology based on its distinguished enzymatic system.