短小芽胞杆菌产碱性木聚糖酶发酵条件的研究

碱性木聚糖酶在碱性条件下催化水解木聚糖,广泛应用于造纸、纺织等领域.着重对短小芽胞杆菌M-11产碱性木聚糖酶的发酵条件进行初步的探索.研究了菌株的生长曲线、确定最佳接种龄为16 h、最佳接种量为1％；确定最适碳源浓度为7％、最适单一氮源为氯化铵、其浓度为1.0％、最适无机盐为氯化铁、其浓度为3 mmol/L；在此基础之上进行6因素3水平的正交试验,确定最适产酶培养基组成:麸皮5％,接种量3％,氯化铵1.2％,氯化铁3.5 mmol/L,硫酸镁0.03％,氯化钠5 mmol/L,磷酸氢二钾0.4％；最适培养条件:接种龄16 h,初始pH 8.0,温度37℃,300 mL摇瓶装液量50 mL,摇床转速220 r/min,发酵周期48 h.通过对发酵条件的优化使发酵液酶活达613 IU/mL.无机氮源为其最适氮源,因此短小芽胞杆菌M-11在碱性木聚糖酶的产品开发上优于短小芽胞杆菌M -26.

Fermentation Conditions of Alkaline Xylanase Production by Bacillus pumilus

Alkaline xylanase catalyzes and hydrolyzes xylan under alkaline conditions,and widely uses in paper making,textile and other fields.This research focuses on the fermentation conditions of alkaline xylanase by Bacillus pumilus(Bm) M-11.The growth curve of bacterial strain was studied,and confirmed the optimum inoculation stadium was at 16 h,and the optimum inoculum was at 1%,the most suitable concentration of carbon source at 7%,the most suitable single nitrogen source was NH4Cl with concentration at 1.0%,the most suitable inorganic salt was FeCl3 at 3 mmol/L.The optimal conditions for enzyme production were studied by a six factors three levels orthogonal test,and confirmed the most suitable medium components as follow: bran 5%,inoculum 3%,NH4Cl 1.2%,FeCl3 3.5 mmol/L,MgSO4 0.03%,NaCl 5 mmol/L,K2HPO4 0.4%.The optimal culture conditions: initial cultural pH 8.0,temperature 37 ℃;50 mL liquid in a 300 mL flask;agitation 220 r/min,inoculation stadium 16 h;fermentation period 48 h.The enzyme activity in supernatant of the fermentation broth was 613 IU/mL.The most suitable nitrogen source was inorganic nitrogen,therefore,Bm M-11 outwent Bm M-26 in developing alkaline xylanase.