Optimization of salts in medium for production of carboxymethylcellulase by a psychrophilic marine bacterium, Psychrobacter aquimaris LBH-10 using two statistical methods

The concentration of four mineral salts in the medium for the production of carboxymethylcellulase (CMCase) by Psychrobacter aquimaris LBH-10 were optimized using orthogonal array method (OAM) and response surface method (RSM) and their results from two statistical methods were compared. The analysis of variance (ANOVA) of data from central composite design (CCD) based on OAM indicated that potassium phosphate gave the highest percentage participation for cell growth as well as production of CMCase. However, their relative participations of four salts for cell growth were different from those for production of CMCase. The ANOVA of results from RSM indicated that highly significant factors (“probe>F” less than 0.0001) for cell growth were K2HPO4 and (NH4)2SO4, whereas those for production of CMCase were K2HPO4, NaCl, and MgSO4·7H2O. The optimal concentration of K2HPO4, NaCl, MgSO4·7H2O, and (NH4)2SO4 for cell growth extracted by Design Expert Software based on RSM were 7.10, 0.84, 0.24, and 0.33 g/L, respectively, whereas those for production of CMCase were 3.00, 0.52, 0.34, and 0.45 g/L. The optimal concentrations of salts for cell growth and production of CMCase using RSM basically coincided with those using OAM as well as those from ‘one-factor-at-a-time’ method. The production of CMCase by P. aquimaris LBH-10 with optimized concentrations of salts was 273.0 U/mL, which was enhanced by 1.27 times higher than the previous report.