在前期研究中，通过比较基因组学分析发现产L-丝氨酸野生型谷氨酸棒杆菌SYPS-062及其突变株SYPS-062-33a之间有12个基因突变。对其中5个差异基因进行回复突变或敲除的研究，发现丙酮酸脱氢酶亚基aceE点突变与突变株SYPS-062-33a副产物积累量直接相关。在此基础上其余7个突变基因对菌株产酸和生长的影响将进一步研究，在高产L-丝氨酸谷氨酸棒杆菌ΔSSAAI中分别敲除这7个基因，发现敲除基因SD36_RS01255后，菌株OD562下降25.8%，L-丝氨酸产量下降26.4%，仅积累19.25 g/L。通过比对NCBI蛋白数据库，对基因SD36_RS01255编码的蛋白进行功能预测分析，发现其编码的蛋白部分区域与质粒pRiA4b ORF-3编码的蛋白类似，参与DNA修复。敲除基因SD36_RS01255影响DNA的修复，从而造成菌株生长和L-丝氨酸产量的下降。而过表达基因SD36_RS01255对谷氨酸棒杆菌ΔSSAAI的生长、L-丝氨酸的产量却未造成显著影响。

In the previous study, mutations were detected by comparative genomics analysis between the wild-type strain Corynebacterium glutamicum SYPS-062 and the mutation strain SYPS-062-33a. The study on five variant genes reversion or deletion revealed that the point mutation of pyruvate dehydrogenase subunit (aceE) was responsible for the more accumulation of by-products in the mutation strain SYPS-062-33a. Based on that, the effect of remaining seven mutant genes on cell growth and L-serine production was further explored. And the seven genes in the high-yield L-serine-producing ΔSSAAI were respectively deleted. After the gene SD36_RS01255 deletion, OD562 decreased by 25.8%, and the titer of L-serine reduced by 26.4% to 19.25 g/L. Subsequently, the functional prediction analysis revealed that the partial region of the protein encoded by SD36_RS01255 was similar to the protein encoded by the plasmid pRiA4b ORF-3 when compared with the NCBI database protein. The deletion of SD36_RS01255 might affect DNA repair, and thus result in slow cell production and L-serine production decline. However, overexpression of SD36_RS01255 had no significant effect on the growth of ΔSSAAI, the titer of L-serine and the accumulation of by-products.