摘要
利用实验室保存的纳豆激酶生产菌Bacillus subtilis Natto NLSSe进行了γ-聚谷氨酸合成研究,在不添加谷氨酸的培养基中合成了分子量在200～300万Da的γ-聚谷氨酸,表明该菌是谷氨酸非依赖型菌.合成纳豆激酶的合适碳、氮源分别是蔗糖和大豆蛋白胨,合成γ-聚谷氨酸的合适碳、氮源分别是柠檬酸和NH4C1.通过正交实验研究了碳、氮源对纳豆激酶和γ-聚谷氨酸联产的影响,结果表明,增加培养基中大豆蛋白胨及柠檬酸的浓度能分别促进纳豆激酶和γ-聚谷氨酸的合成,而不抑制另一产物的合成,有利于纳豆激酶和γ-聚谷氨酸的联产.在大豆蛋白胨10g/L,NH4C19g/L,柠檬酸15g/L时,纳豆激酶酶活为121.2U/mL,γ-聚谷氨酸产量为1.1g/L,均达到了单独合成时的水平.
The synthesis of γ-poly glutamic acid （γ-PGA） by the strain Bacillus subtilis Natto NLSSe which can be used to synthesize nattokinase was investigated. γ-PGA was synthesized in the medium without the addition of L-glutamic acid, showing that the strain was a L-glutamic acid-independent bacterium. The molecular weight of the γ-PGA was about 2-3 million Dalton. The suitable carbon and nitrogen sources for the synthesis of nattokinase were sucrose and soya peptone respectively. The suitable carbon and nitrogen sources for the synthesis of γ-PGA were citric acid and NH4Cl respectively. The results of orthogonal experiments showed that increasing the concentrations of soya peptone and citric acid could enhance the synthesis of nattokinase and γ-PGA respectively, in the meantime the synthesis did not result in restraint formation between the two products. This merit was beneficial to the co-production. The yields of both products could achieve the levels of the single synthesis when the concentrations of soya peptone, NH4Cl and citric acid were 10, 9, 15 g/L respectively, the activity of nattokinase reached 121.2 U/mL, and the concentration of γ-PGA reached 1.1 g/L.
出处
《过程工程学报》
EI
CAS
CSCD
北大核心
2008年第1期120-124,共5页
The Chinese Journal of Process Engineering
基金
国家重点基础研究发展规划(973)基金资助项目(编号:2007CB714301)
