为提高出芽短梗霉liamocins合成能力,分别过表达了出芽短梗霉P30的乙酰-CoA合成相关基因,包括乙酰-CoA合酶编码基因(ACS1)、ATP-依赖性柠檬酸裂解酶编码基因(ACL)、苹果酸酶编码基因(ME)、丙酮酸羧化酶编码基因(PYC1)。重组菌株的liamocins产量分别提高了8.19%、93.74%、13.49%和17.12%,其中过表达ACL的提升效果最为明显,但该基因的转录水平仅提高了0.94倍,这说明ACL为出芽短梗霉 P30合成liamocins的关键基因,liamocins合成的能力或许受ACL转录水平的限制。结果表明,强化乙酰-CoA合成可以提高liamocins产量,而其中的ACL基因对其合成至关重要。研究为解决liamocins合成过程中碳代谢流前体不足问题提供了解决思路。
To improve liamocins synthesis in Aureobasidium pullulans, acetyl-CoA synthase encoded by ACS1, ATP-dependent citrate lyase (ACL), malate enzyme (ME) and pyruvate carboxylase (PYC1) were overexpressed in Aureobasidium pullulans P30. After overexpression of ACS1, ACL, ME and PYC1, the yield of liamocins increased by 8.19%, 93.74%, 13.49% and 17.12%, respectively. Among them, overexpression of ACL achieved the highest liamocins production (19.44 g/L), even if its transcription level only increased by 94%, indicating that ACL is the key enzyme in liamocins synthesis. Elevation of the ACL transcription level may help for further improving the liamocins' production. The results indicated that acetyl-CoA synthesis pathway was important for liamocins production. The findings in this study provide a new way for enhancing the synthesis of liamocins by providing sufficient precursors.
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