以玉米芯木聚糖为碳源的草菇木聚糖酶的发酵条件

Fermentation Conditions of Xlyanase Produced by Volvariella volvacea with Xylan Extracted from Corncob

在玉米芯木聚糖的碱法提取中,玉米芯木聚糖在80℃抽提120min的抽提率较高,还原糖质量分数较低,同时,抽提液的颜色较浅,明显优于121℃抽提30min.以80℃抽提的木聚糖为诱导,草菇产生的木聚糖酶的酶活比121℃抽提的木聚糖的酶活高.以80℃抽提的木聚糖为碳源,通过正交试验,设计出适合草菇生长和产生木聚糖酶的发酵条件.培养基组成为:木聚糖15g/L,(NH4)2SO42.5g/L,Tween 803g/L,酵母膏1g/L,KH2PO41g/L,MgSO4·7H2O0.6g/L,微量元素0.0005g/L.pH7.0,40℃下150r/min培养4d,此时酶活达32.4IU/mL.

By comparing two alikali extracting methods, the method of socking corncob at 80 ℃ for 120 min could obtain a higher xylan yield, lower reducing sugar, and lighter extracting fluid color. This method was better than that of socking at 121 ℃ for 30 min. With the xylan extracted at 80 ℃ as the inducer, the enzyme activity was higher than that of xylan extracted at 121℃. When the xylan extracted at 80 ℃ was used as carbon source, an orthogonal experiment was carried out for optimization of Volvariella volvacea fermentation to produce extracellular xylanase. The medium (g/L) contained xylan 15, (NH_(4))_(2)SO_(4 ) 2.5, Tween-80 3, yeast extract 1, KH_(2)PO_(4) 1, MgSO_(4)·7H_(2)O 0.6, and trace elements 0.000 5. pH of the medium was 7.0. The flasks were incubated at 40℃ with gyratory shaking at 150 r/min for 4 d. The xylanase activity of the culture filtrate was 32.4 IU/mL.