Fermentation optimization of high-yield β-mannanase from B.amyloliquefaciens T12 and prebiotic activity of degradation product
The purpose of the experiment was to increase the production of mannanase from B.amyloliquefaciens T12 and verify the prebiotic activity of the hydrolysate.The fermentation conditions were optimized,and the effects of eight groups of culture variables on the enzyme activity were investigated by single factor test.Three main factors were screened out from the single factor conditions affecting the enzyme activity of β-mannanase,and the center point of the main factors was determined by the steepest climbing test.Finally,Box-Behnken method was used to design and carry out the three factors and three levels test,which was verified by Desgin Expert results analysis and subsequent experiments.The results showed that the optimum fermentation conditions were as follows:Konjac powder concentration 10.4 g/L,yeast extract 6.37 g/L,liquid volume 100 mL,inoculation volume 2%(volume fraction),fermentation period 12～16 h,initial pH 6.5,and other conditions unchanged.The enzyme activity reached 15264.92 U/mL.The probiotic activity of mannooligosaccharides hydrolyzed by β-mannanase was analyzed.It was found that mannooligosaccharides could promote the growth of Lactobacillus and Lactobacillus casei,and the probiotic medium could inhibit the proliferation of pathogenic bacteria.
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