Screening Of An Alkaline Cmcase-Producing Strain And The Optimization Of Its Fermentation Condition

Objective: Alkaline Carboxymethyl Cellulase (CMCase) is an attractive enzyme for the textile, laundry, pulp, and paper industries; however, commercial preparations with sufficient activity at alkaline conditions are scarce.Methods: High CMCase-producing bacterial isolate, SX9-4, was screened out from soil bacteria, which was identified as Flavobacterium sp. on the basis of 16S rDNA sequencing.Results: The optimum pH and temperature for CMCase reaction were 8.0 and 55 degrees C, respectively. Alkaline CMCase was stable over wide pH (3.0-10.6) and temperature (25-55 degrees C) ranges. Enzyme activity was significantly inhibited by the bivalent cations Mn2+ and Cu2+, and was activated by Fe2+. To improve the alkaline CMCase production of SX9-4, fermentation parameters were selected through one-factor-at-a-time and further carried out by response surface methodologies based on a central composite design.Conclusion: High CMCase production (57.18 U/mL) was achieved under the optimal conditions: 10.53 g/L carboxymethylcellulose sodium, 7.74 g/L glucose, 13.71 g/L peptone, and 5.27 g/L ammonium oxalate.