黑曲霉变异株AU 55发酵菊芋汁产菊粉酶的研究

为提高菊粉酶活力,以菊芋汁为主要培养基成分,对一株产菊粉酶的黑曲霉(Aspergillus niger)变异株AU-55发酵产酶历程和发酵工艺条件进行研究。结果表明,菊芋汁中还原糖的含量为3.4 g.L-1,菊糖含量约为121.3 g.L-1;黑曲霉AU-55在基础发酵培养基中培养,发酵液中菊粉酶活力、糖度、酸度、菌体生物量随着发酵时间的不断延长而变化,96 h菊粉酶活力达到最大;菊芋汁添加量、玉米浆添加量、初始pH、接种量对黑曲霉AU-55菊粉酶活力的影响均显著,优化后的发酵工艺参数为:菊芋汁250.0 mL.L-1,玉米浆20.0 g.L-1,NH4H2PO45.0 g.L-1,MgSO4.7H2O 0.5 g.L-1,NaCl 3.0 g.L-1,初始pH 6.5,接种量35.0 g.L-1,30℃,200 r/min下,培养4 d,所得菊粉酶活力最高达42.3 U.mL-1。

Study on Inulinase Production from Jerusalem artichoke Juice Fermented by Aspergillus niger Mutant AU 55

To obtain inulinase with high activity,fermentation process and optimization of fermentation conditions of an Aspergillus niger mutant AU-55 in Jerusalem artichoke juice(JAJ) was investigated.The results showed that the reduced sugar content and inulin content in JAJ was 3.4 g·L-1 and 121.3 g·L-1;inulinase activity,remained sugar,acidity and biomass of basal fermentation medium fermented with Aspergillus niger AU-55 changed with time,inulinase activity reached maximum at 96h;The amount of JAJ,the content of corn steep liquor,initial pH and inoculums all had significant effect on inulinase activity of Aspergillus niger AU-55.Optimized conditions were JAJ 250.0 mL·L-1,corn steep liquor 20.0 g·L-1,NH4H2PO4 5.0 g·L-1,MgSO4·7H2O 0.5 g·L-1,NaCl 3.0 g·L-1,initial pH 6.5,inoculums 35.0 g·L-1,30 ℃,200 r/min,and fermentation time 4 d,inulinase activity was up to 42.3 U·mL-1.