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Optimization of Fermentation Medium for Producing Uridine Phosphorylase by Lactobacillus brevis

WANG Wei-jie1,LI Hong-mei1,*,DENG Long-hua1,GAO Lu-jiao2,HUANG Yan-qing2   

  1. 1. School of Medical Instrument and Food Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China;
    2. East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shanghai 200090, China
  • Online:2013-09-15 Published:2013-09-27
  • Contact: LI Hong-mei

Abstract:

The culture medium and fermentation conditions for producing uridine phosphorylase by Lactobacillus brevis was
optimized by response surface methodology. On the basis of glucose-yeast extract culture medium, four factors such as glucose
concentration (P = 0.002), yeast extract (P = 0.054), phosphate group (P = 0.059) and uridine (P = 0.001) were identified as
important factors that affect the production of uridine phosphorylase by single factor and Placket-Burman designs. These factors
were further examined through steepest ascent path method to find the maximum response region and optimized by response
surface Box-Behnken design. The optimal fermentation medium comprised NaCl 5 g/L, glucose 18.30 g/L, yeast extract 15.71 g/L,
peptone 15 g/L, phosphate group 3.99 g/L, carnine 20 mmol/L and uridine concentration 21.38 mmol/L at initial pH of 8.0.
The optimal culture conditions were shaking speed of 110 r/min, culture temperature of 32 ℃, fermentation time of 14 h and
inoculum amount of 1.0%. Under the optimized conditions, the production of uridine phosphorylase by Lactobacillus brevis
was 1.325 U/mg wet bacteria, which exhibited an increase by 50.0% compared with non-optimization.

Key words: Lactobacillus brevis, uridine phosphorylase, Box-Behnken design, response surface methodology

CLC Number: