Enhanced alkaline catalase production by Serratia marcescens FZSF01: enzyme purification, characterization, and recombinant expression

ABSTRACT

Background: Catalase (CAT) is an important enzyme that degrades H2O2 into H2O and O2. To obtain an efficient catalase, in this study, a new strain of high catalase-producing Serratia marcescens, named FZSF01, was screened and its catalase was purified and characterized. Results: After optimization of fermentation conditions, the yield of catalase produced by this strain was as high as 51,468 U/ml. This catalase was further purified using two steps: DEAE-fast flow and Sephedex-G150. The purified catalase showed a specific activity of 197,575 U/mg with a molecular mass of 58 kDa. This catalase exhibited high activity at 20­70°C and pH 5.0­11.0. Km of the catalase was approximately 68 mM, and Vmax was 1886.8 mol/min mg. This catalase was further identified by LC­MS/MS, and the encoding gene was cloned and expressed in Escherichia coli BL21 (DE3) with a production of 17,267 ± 2037 U/ml. Conclusions: To our knowledge, these results represent one of the highest fermentation levels reported among current catalase-producing strains. This FZSF01 catalase may be suitable for several industrial applications that comprise exposure to alkaline conditions and under a wide range of temperatures.