果胶降解菌的筛选、鉴定及发酵产酶条件优化

Screening and Identification of Pectin-degrading Bacteria and Optimization of Pectinase-producing Condition

为了获得高产果胶酶菌株,从腐烂水果中分离到1株产果胶酶真菌.采用果胶作为唯一碳源平板,结合平板颜色变化、D/d值与果胶酶活力测定等方法进行筛选,并对高产果胶酶菌株JX20进行菌落形态特征、显微结构观察以及ITS-rDNA序列进行分析;进而通过单因素试验优化菌株JX20产果胶酶的发酵产酶条件,在确定了最优区间后利用响应面法对发酵产酶条件进行优化.结果表明,该菌株经鉴定为黄曲霉(Aspergillus flavus JX20).其最适发酵优化条件为麦芽糖0.95%,酵母膏1.87%,接种量2.0%,初始pH 5.06,发酵周期为72 h,培养温度为31.34℃.在此条件下,该菌的果胶酶活力达到245.38 U/mL.这将为进一步采用生物法降解果胶提供了试验依据.

To obtain the high-yield pectinase strain,a pectinase-producing fungi was isolated from the rotten fruit.The Lugol's solution staining plate separation method which contains the pectin as the sole carbon source was used,combined with D/d value,flat color changes and determination of pectinase activity.Morphology,physiology and biochemistry research coupled with ITS-rDNA sequence and analysis showed that the strain JX20 was Aspergillus sp.Single-factor method was used for optimizing the fermentation condition.The optimum pectinase-producing conditions were as follows:culture media containing maltose 0.95%,yeast cream 1.87%,inoculum amount 2.0%(v/v),initial pH of 5.06,at 31.34℃shaking for 72 h.Under this fermentation conditions,the activity pectinase of JX20 reached 245.58 U/mL.This will provide experimental basis for further biodegradation of pectin.