【摘要】 分别以多孔陶瓷和浮石为载体吸附法固定重组大肠杆菌(Escherichia coli JM 109-pLF3)表达β-葡聚糖酶.研究了载体量、转速、温度、pH等条件对固定化细胞产酶的影响.结果表明,以多孔陶瓷和浮石为载体固定化细胞发酵可以大大提高产酶效率,二者均可有效吸附重组大肠杆菌,发酵液的酶活分别达到97 U/mL和73 U/mL,比悬浮液体发酵提高了2~3倍;载体量、转速、温度对产酶的影响较大,多孔陶瓷和浮石的最佳装载量分别为20 g/100 mL培养基和8g/100 mL培养基,最佳转速为200 r/min,最佳培养温度为37℃;发酵液pH值对细胞产酶的影响较小,pH值6.0~8.0之间发酵液的酶活力变化不大.重复批次发酵结果表明,固定化发酵具有良好的重复使用能力,在连续10批次实验中,多孔陶瓷载体和浮石载体固定化发酵的酶活力分别不低于91 U/mL和72 U/mL.更多还原

【Abstract】 In order to improve the productivity of β-glucanase,porous ceramic carrier and broken pumice were applied to immobilize recombinant Escherichia coli JM 109(pLF3),respectively.The factors influencing enzyme activity such as the amount of the carriers,rotation rate,temperature and pH value were investigated.The results indicated that the production of β-glucanase was significantly improved by immobilization of recombinant E.coli cells with porous ceramic and pumice as carriers.Both of the carriers were actively colonized by recombinant Escherichia coli and the enzyme activities in the medium reached 97 U/mL and 73 U/mL after 48 h cultivation respectively,which were 2-3 times higher than those in suspension culture under similar cultivation conditions.The optimum amount of porous ceramic and pumice were 20 g/100 mL medium and 8 g/100 mL medium,respectively.The optimum rotation rate was found to be 200 r/min,and the cultivation temperature was 37℃.The enzyme activity in medium could be kept more or less constant when the pH value was changed from 6.0 to 8.0.Repeated batch fermentation with immobilized cells demonstrated that immobilized cells were highly reusable and the enzyme activity in the medium was not less than 91 U/mL and 72 U/mL for porous ceramic and pumice as carriers during 10 repeated batch cultivations,respectively.更多还原