纳豆芽孢杆菌产VK2菌株的NTG与N＋注入复合诱变选育

以纳豆芽孢杆菌BN-2-6为出发菌株，利用亚硝基胍（NTG）和N＋注入复合诱变选育产维生素K2的突变株。经过NTG诱变后得到突变株BN-N30—1，其维生素K2的产量提高了53％，继而采用低能N＋注入技术进行处理得到突变株BN-P15—11-1，维生素K2的产量比BN—N30—1提高了96％，比原始菌株提高了166％。结果表明，对纳豆芽孢杆菌BN-2-6进行NTG和低能N＋注入复合诱变的效果明显，突变菌株维生素K2的产量显著提高。

Mutagenesis by NTG and N＋ implantation for breeding of Bacillus natto producing vitamin K2

Using Bacillus natto as the original strain, the combined mutation including N-methyl-N-nitro-N-nitroso- guanidine （NTG） and N＋ implantation were conducted to obtain vitamin K2 producing mutants. After the NTG mutation, a mutant strain named BN-N30-1 was obtained and its yield of vitamin K2 increased by 53%, if compared with that of the original strain BN-2-6. Then the mutant strain was further mutated by N＋ implantation. As a result, the mutant strain named BN-P15-11-1 was obtained and its vitamin K2 yield increased by 96% over that of the strain BN-N30-1 and by 166% over that of the original strain BN-2-6, respectively. The results showed that the NTG and N＋ implantation mutations were effective methods for breeding Bacillus natto and the enhancement of vitamin K2 production was obvious.