Engineering acetyl-CoA metabolic shortcut for eco-friendly production of polyketides triacetic acid lactone in Yarrowia lipolytica
Engineering acetyl-CoA metabolic shortcut for eco-friendly production of polyketides triacetic acid lactone in Yarrowia lipolytica
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DOI：
10.1016/j.ymben.2019.08.017
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发表时间：
2019-12-01
影响因子：
8.4
通讯作者：
Xu, Peng
中科院分区：
文献类型：
--
作者：
Liu, Huan;Marsafari, Monireh;Xu, Peng
乙酰辅酶A是连接糖酵解、克雷布斯循环和脂肪酸合成酶的代谢中心节点。植物源聚酮化合物是由乙酰辅酶A和丙二酰辅酶A组装而成的一类具有多种生物活性的生物化合物。利用微生物生物转化被认为是从可再生原料大规模生产聚酮化合物的可行途径。目前的大多数聚酮化合物生产平台依赖于冗长的糖酵解步骤来提供乙酰辅酶A，乙酰辅酶A固有地受到代谢昂贵的辅因子/ATP需求的复杂调节的影响。使用最简单的聚酮三乙酸内酯（TAL）作为测试床分子，我们证明，在产油酵母（Yarrowia lipolytica）的乙酸摄取途径可以作为乙酰辅酶A的捷径，以实现代谢最佳化生产聚酮。我们确定了代谢瓶颈，以重新布线乙酸利用有效的TAL生产在Y。解脂作用，包括产生乙酰辅酶A、丙二酰辅酶A和NADPH的驱动力。该工程菌株，与内源性乙酰辅酶A羧化酶（ACC 1），苹果酸酶（MAE 1）和细菌来源的胞质丙酮酸脱氢酶（PDH）的过表达，提供了强大的TAL生产与滴度高达4.76 g/L，从工业冰川乙酸在摇瓶中，代表8.5倍的提高，比亲本菌株。乙酸转化为TAL的转化率（0.149 g/g）达到理论最大产率的31.9%。通过这种乙酰辅酶A代谢捷径的碳通量超过了天然糖酵解途径提供的碳通量。通过合成气发酵或多相催化（甲醇羰基化）可以低成本大量生产醋酸。这种替代碳源相对于葡萄糖具有代谢优势，可以释放固有的途径限制，并实现高的碳转化效率和成本效益。这项工作还强调了低成本的乙酸可以通过产油酵母物种以生态友好和具有成本效益的方式可持续地升级为高价值的聚酮化合物。
Acetyl-CoA is the central metabolic node connecting glycolysis, Krebs cycle and fatty acids synthase. Plant-derived polyketides, are assembled from acetyl-CoA and malonyl-CoA, represent a large family of biological compounds with diversified bioactivity. Harnessing microbial bioconversion is considered as a feasible approach to large-scale production of polyketides from renewable feedstocks. Most of the current polyketide production platform relied on the lengthy glycolytic steps to provide acetyl-CoA, which inherently suffers from complex regulation with metabolically-costly cofactor/ATP requirements. Using the simplest polyketide triacetic acid lactone (TAL) as a testbed molecule, we demonstrate that acetate uptake pathway in oleaginous yeast (Yarrowia lipolytica) could function as an acetyl-CoA shortcut to achieve metabolic optimality in producing polyketides. We identified the metabolic bottlenecks to rewire acetate utilization for efficient TAL production in Y. lipolytica, including generation of the driving force for acetyl-CoA, malonyl-CoA and NADPH. The engineered strain, with the overexpression of endogenous acetyl-CoA carboxylase (ACC1), malic enzyme (MAE1) and a bacteria-derived cytosolic pyruvate dehydrogenase (PDH), affords robust TAL production with titer up to 4.76 g/L from industrial glacier acetic acid in shake flasks, representing 8.5-times improvement over the parental strain. The acetate-to-TAL conversion ratio (0.149 g/g) reaches 31.9% of the theoretical maximum yield. The carbon flux through this acetyl-CoA metabolic shortcut exceeds the carbon flux afforded by the native glycolytic pathways. Potentially, acetic acid could be manufactured in large-quantity at low-cost from Syngas fermentation or heterogenous catalysis (methanol carbonylation). This alternative carbon sources present a metabolic advantage over glucose to unleash intrinsic pathway limitations and achieve high carbon conversion efficiency and cost-efficiency. This work also highlights that low-cost acetic acid could be sustainably upgraded to high-value polyketides by oleaginous yeast species in an eco-friendly and cost-efficient manner.