摘要
利用了低能N+注入产色氨酸酶大肠杆菌Escherichia coli进行诱变选育。首先进行了离子注入条件及参数的探索,确立了以15%甘油作为保护剂,N+注入能量10keV,剂量13×1014cm-2的离子注入参数。反复筛选和连续突变后,获得高产色氨酸酶大肠杆菌,和出发菌株相比,其生物量和色氨酸酶活性均有所提高。经过发酵规模逐步扩大和酶促反应体系放大,菌体生物量可达8.2gww·L-1,其酶法催化合成L-色氨酸的产量高达110g·L-1。该菌继代培养遗传性能稳定,可操作性强,有很好的工业化前景。
In this paper, the mutation breeding on Escherichia coli producing tryptophanase was studied after low energy N^＋ ion beam implantation. Parameters in the N^＋ ion beam implantation were firstly determined. It has been indicated that a high mutation rate of E.coli could be obtained by N^＋ implantation with 10 keV and 13×10^14cm^-2 when glycerin at 15 % concentration used as protector. After continuous mutagenicity a high-yield tryptopha- nase-producing strain has been screened out and both of its biomass and enzymatic activity are higher than the previous levels respectively. The results of scale-up production show that the biomass could be reach 8.2 gw·L^-1 and 110 g L-tryptophan could be formed in the volume of 1L enzymatic reaction system. In addition, the characteristics of its stable descend ability and easy operation make it a promising strain for industrialization.
出处
《辐射研究与辐射工艺学报》
CAS
CSCD
2009年第3期167-172,共6页
Journal of Radiation Research and Radiation Processing
关键词
离子注入
L-色氨酸
大肠杆菌
育种
Inn implantation, L-tryptophan, Escherichia coli, Breeding
