FOOD SCIENCE ›› 2020, Vol. 41 ›› Issue (10): 172-179.doi: 10.7506/spkx1002-6630-20190314-184

• Bioengineering • Previous Articles     Next Articles

Optimization of Fermentation Conditions for Xylosidase Production by Aspergillus niger

TANG Yong, DING Honghao, CAI Jun   

  1. (Key Laboratory of Fermentation Engineering, Ministry of Education, Hubei Key Laboratory of Industrial Microbiology, Hubei Provincial Cooperative Innovation Center of Industrial Fermentation, Hubei University of Technology, Wuhan 430068, China)
  • Received:2020-05-18 Revised:2020-05-18 Online:2020-05-25 Published:2020-05-15

Abstract: In order to fully utilize corn cob powder as an agricultural by-product, the submerged fermentation of Aspergillus niger using corn cob powder as a substrate was optimized for enhanced xylosidase activity. Firstly, one-factor-at-a-time method was used to investigate the effects of fermentation period, temperature, inoculum size, initial fermentation pH, medium volume and shaker speed on xylosidase activity. The results showed that a fermentation period of 144 h, a temperature of 34 ℃, an inoculum size of 7%, an initial fermentation pH of 3.0, a shaking speed of 180 r/min, and a medium volume of 110 mL in 300-mL shake flasks were found to be the best conditions. Further, using the Plackett-Burman design, lowest addition experiments, the steepest ascent method, and response surface methodology with central composite design, the optimal levels for medium components were determined as follows: corn kernel powder 31.55 g/L, yeast powder 8.00 g/L, peptone 5.48 g/L, magnesium sulfate 0.70 g/L, sodium chloride 1.00 g/L, and calcium chloride 1.50 g/L. A quadratic polynomial model was developed with a determination coefficient R2 of 0.991 0, and an adjustment coefficient R2 of 0.982 9. The analysis of variance (ANOVA) showed that the model was significant with a P value greater than 0.05 for lack-of-fit, supporting its use for the theoretical prediction of enzyme production. Under the optimized conditions, an 8.89-fold increase was observed in xylosidase activity of Aspergillus niger.

Key words: Aspergillus niger, xylosidase, fermentation, response surface methodology

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