固态发酵产木聚糖酶条件优化及其酶学性质初步研究

摘要

以树干毕赤酵母作为发酵菌株对其固态发酵产木聚糖酶的条件进行优化,并对木聚糖酶的性质进行初步研究.由试验结果可知,最优培养条件为玉米芯与小麦麸皮质量比为1∶1,初始水分含量为80％,培养基的基质密度为0.7～0.9 g/mL.28℃下培养9 d,木聚糖酶活力最高达到5 536 U/g.该酶的最适反应pH为6,在pH 6～8时酶活稳定性较好,保温1h后仍可保留90％以上的酶活；最适温度为60℃,在50～60℃时热稳定性较好；Zn2+、Ca2+和Cu2+对木聚糖酶的活力具有微弱促进作用,Fe2+、Fe3+和Mn2+对木聚糖酶的抑制作用比较明显.%In this paper,we optimized the solid state fermentation conditions of xylanase by using Pichia stipitis,and preliminarily studied the properties of xylanase.The optimum culture conditions were as follows:the mass ratio of corncob to wheat bran 1∶1,initial moisture content 80％,medium density 0.7 to 0.9 g/mL,culture temperature 28 ℃,and culture time 9 days; and the highest activity of xylanase was up to 5 536 U/g.The most proper pH value of xylanase was 6; and the xylanase had good stability at a pH range from 6 to 8,and could keep 90％ activity or above after keeping the temperature for an hour.The most proper temperature was 60 ℃,and the xylanase had a better thermal stability at 50℃ to 60 ℃.The metal ions of Zn2+、Ca2+and Cu2+ had a weak effect on promoting the activity of xylanase,and the metal ions of Fe2+,Fe3+ and Mn2+ had a obvious effects on inhibiting xylanase.