高产芽孢杆菌MS12木聚糖酶发酵条件优化及酶学性质研究

Optimization of Fermentation Conditions and Enzymatic Properties of Xylanase from Bacillus sp. strain MS12

从昆明某磷矿土壤中筛选出一株产木聚糖酶能力较强的菌株——MS12,通过单因素试验初步优化了该菌株的产酶条件.试验结果显示,该菌株最佳产酶培养基为玉米芯粉50g/L、麸皮40g/L、NH4Cl10g/L、CaCl25g/L、NaHPO42g/L,pH自然;最佳产酶发酵条件为30℃,180r/min,装样量30mL/250mL三角瓶,震荡培养96h.经测定,菌株MS12所产木聚糖酶的最适反应温度为65℃,最适反应pH值为7.0,具有较好的pH稳定性.1mmol/LNa^+、Ba2+和10mmol/LCa^2+、Mg^2+对酶活有促进作用,Ag^+对酶活有明显的抑制作用.

In this study,a strain MS12 with strong ability to produce xylanase was screened from phosphate rock soil in Kunming mine. Single factors such as nitrogen source,fermentation temperature and fermentation time were screened. Fermentation medium and fermentation conditions of Bacillus sp. strain MS12 in producing xylanase were optimized. The results showed that the optimal enzyme production medium was corncob 50 g/L,bran 40 g/L,NH4Cl 10 g/L,CaCl2 5 g/L,NaHPO4 2 g/L,and pH natural. The optimum conditions for enzymatic fermentation were 30 ℃,180 r/min,30 mL/250 mL,and shaking culture 96 h. The optimal temperature and pH for enzyme activity were 65 ℃ and 7.0,respectively. The enzyme showed good pH-stability. The enzyme activity was stimulated by Na^+, Ba^2+,Ca^2+,and Mg^2+. Ag^+ almost had no activation or inhibition on the enzyme.