China Animal Husbandry and Veterinary Medicine ›› 2020, Vol. 47 ›› Issue (1): 44-52.doi: 10.16431/j.cnki.1671-7236.2020.01.006

• Animal Nutrition and Feed Science • Previous Articles     Next Articles

Optimization of the Fermentation Conditions of Recombinant B.subtilis WB600 Produced Keratinase

LIAO Chaoyong1, ZHANG Tieying1, LIU Junli1, SUI Jingwei2   

  1. 1. State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing 100193, China;
    2. College of Animal Science and Technology, Gansu Agricultural University, Lanzhou 730070, China
  • Received:2019-05-09 Online:2020-01-20 Published:2020-01-17

Abstract: The aim of this experiment was to optimize the fermentation conditions of the constructed keratinase recombinant B.subtilis WB600 strain WB600-K,and obtain the optimal enzyme production conditions in order to increase the yield of recombinant keratinase;At the same time,the combination optimization between different types of carbon sources and different nitrogen sources was studied in order to obtain a low-cost recombinant fermentative medium formula.The results showed that when the fermentation D600 nm=1.0,and 0.5% xylose was added to induce fermentation,the expression of keratinase was best in the recombinant WB600-K (P<0.05).As a carbon source,sorbitol could significantly increase the activity of the recombinant strain WB600-K keratinase (P<0.05),but the cost was too high to be a source of mixed carbon sources.The combination of different carbon sources (glucose,corn flour,molasses and glycerin) could significantly increase the activity of keratinase (P<0.05).The combination of different kinds of nitrogen sources (peptone,yeast powder,soybean meal and urea) significantly increased the activity of keratinase less than single nitrogen source (peptone) (P<0.05).The WB600-K had the highest keratinase activity at 48 h after induction of fermentation (P<0.05).The overall experimental optimization results showed that,at the condition of corn flour 5.1 g/L,glucose 5.9 g/L,molasses 5.9 g/L,glycerol 3.0 g/L,peptone 20 g/L,NaCl 10 g/L,0.5% xylose was added when fermentation D600 nm=1.0,and 48 h fermentation,the activity of keratinase could be increased significantly (P<0.05),which was 56.9 U/mL and 49.74% higher than that in initial culture conditions.In summary,fermentation under optimized fermentation conditions could increase the activity of recombinant strain WB600-K keratinase,which laid a foundation for the industrial production of keratinase.

Key words: B.subtilis WB600; keratinase; fermentative conditions; optimization

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