基于静态与动态调控的巴氏醋酸杆菌乙酸耐受性研究
首发时间:2020-12-30
摘要:高浓度醋酸生产对醋酸菌细胞生长和产物合成产生严重的反馈抑制作用,是醋酸产量和生产强度难以提高的瓶颈问题。本研究以食醋酿造工业菌株Acetobacter pasteurianus CICIM B7003为研究对象,通过TCA循环中关键乙酸耐受酶的鉴定、静态和动态调控,探究了不同初始乙酸浓度条件下细胞生长、耐酸和产酸能力的影响。乙酰合成酶(Acs1)和琥珀酰-CoA:乙酸CoA-转移酶(AarC)的强组成型过表达可以显著提高巴氏醋酸杆菌在无初始乙酸胁迫下的细胞适应度,其比生长率较原始菌分别提高了16.2%和38.7%,乙酸产量提高了42.0%和23.5%。在含有20 g/L初始乙酸胁迫条件下,酸压力驱动型启动子PgroESL介导的ACS1和AarC的动态调控与组成型启动子Ptuf的静态调控相比,细胞生长速率提高了56.4%和89.2%。尤其是工程菌株A.P./pAR-PgroESL-acs1表现出最高的乙酸产量达35.86 g/L,比原始菌株提高了12.1%。在高浓度的初始乙酸胁迫压力下,压力驱动型启动子介导的动态调控可以有效缓解细胞静态强化调控引起的细胞生长和产酸负担,改善巴氏醋酸杆菌在高浓度乙酸条件下的细胞适应度。
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Study on acetic acid tolerance of Acetobacter pasteurianus based on static and dynamic regulation
Abstract:High concentration acetic acid has a serious feedback inhibition effect on the cell growth and product synthesis of acetic acid bacteria. In this study, the vinegar brewing industrial strain Acetobacter pasteurianus CICIM B7003 was used as the research object. By static and dynamic regulation of the key acetic acid tolerance enzymes in the TCA cycle, the cell growth, acid tolerance and acid production capacity under different initial acetic acid concentrations were investigated. The strong constitutive expression of acetylsynthase (Acs1) and succinyl-COA: acetic acid CoA-transferase (AarC) could significantly improve the cell fitness of Acetobacter pasteurianus in absence of initial acetic acid stress, and the growth rate was 16.2% and 38.7% than that of A.P.B7003, respectively, and the yield of acetic acid increased by 42.0% and 23.5%. In the presence of 20 g/L initial acetic acid, dynamic regulation of Acs1 and AarC mediated by acid-driven promoter PgroESL were 56.4% and 89.2% higher than that of constitutive promoter Ptuf. In particularly, A.P./pAR-PgroESL-acs1 showed the highest acetic acid yield of 35.86 g/L, which was 12.1% higher than that of the original strain A.P.B7003. Under high concentration of initial acetic acid stress, dynamic regulation mediated by pressure-driven promoter could effectively alleviate the burden of cell growth and acid production caused by static overexpression, resulting in an improved cell fitness in A. pasteurianus.
Keywords: A. pasteurianus acetic acid assimilation static regulation, dynamic regulation
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基于静态与动态调控的巴氏醋酸杆菌乙酸耐受性研究
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