中文摘要：

苯基乳酸（phenyllacticacid，PLA）耐受性菌株的筛选能够有效降低PLA对生产菌株的抑制作用，有利于PLA产量的提高。通过紫外诱变的方法筛选耐受PLA的菌株，并应用于PLA的合成。以EscherichiacoliBL21（DE3）作为原始出发菌株，通过紫外诱变的方法诱变筛选获得一株耐受PLA突变菌株E.coliZ2016（CCTCC保藏编号M2016332）。以E.coliZ2016为宿主菌，分别构建了重组菌株E.coliZ2016pET-28a-ldhY52V和E.coliZ2016pET-28a-ldhL用于D-和L-苯基乳酸的合成。结果表明：E.coliZ2016在含有1g/LD-PLA的培养基中能够正常生长；重组突变菌株E.coliZ2016pET-28a-ldhY52V和E.coliZ2016pET-28a-ldhL全细胞合成D-PLA和L-PLA产量分别为6.75、6.97g/（L·h），较重组出发菌株分别提高了14.02%和8.95%；分批补加底物反应120min，E.coliZ2016pET-28aldhY52V得到的D-PLA为20.02g/L，较对照组提高22.17%，转化率为90.07%；E.coliZ2016pET-28a-ldhL得到的L-PLA产量为20.87g/L，较对照组提高16.85%，最终转化率为91.24%。筛选耐受性菌株是提高PLA产量的有效途径。

英文摘要：

Screening phenyllactic acid(PLA)-resistant strains enables effective reduction of the inhibitory effect of PLA onthe synthesis process and thus an increase in PLA production.In this report,Escherichia coli BL21(DE3)was mutagenized byUV irradiation and screened for a mutant resistant to PLA,E.coli Z2016(CCTCC Accession No.M2016332).E.coli Z2016was used the host strain to construct recombinant strains E.coli Z2016pET-28a-ldhY52V and E.coli Z2016pET-28a-ldhL forthe synthesis of D-and L-PLA.The results showed that E.coli Z2016was able to grow normally in a medium containing1g/L D-PLA.The production of D-and L-PLA by the recombinant strains were6.75and6.97g/(L·h),which were increasedby14.02%and8.95%as compared to those produced by the original strain,respectively.During120min of fed-batchfermentation,the production of D-PLA by E.coli Z2016pET-28a-ldhY52V was20.02g/L with a conversion rate of90.97%,which was increased by22.17%as compared to that produced by the control.The L-PLA concentration produced byE.coli Z2016pET-28a-ldhL was20.87g/L,which was increased by16.85%as compared to produced by the control,witha conversion rate of91.24%.Accordingly,the use of PLA-resistant strains provided an effective method to increase PLA production.