Aeromonas hydrophila 4AK4 normally produces the copolymer of 3-hydroxybutyrate and 3-hydroxyhexanoate (PHBHHx) using lauric acid as the carbon source. In this study we reported the metabolic engineering of A. hydrophila 4AK4 for the production of polyhydroxyalkanoate (PHA) using acetate as a main carbon source. Recombinant A. hydrophila overexpressing β-ketothiolase and acetoacetyl-CoA reductase could accumulate poly-3-hydroxybutyrate (PHB) from acetate with a polymer content of 1.39 wt%. Further overexpression of acetate kinase/phosphotransacetylase and acetyl-CoA synthetase improved PHB content to 8.75 wt% and 19.82 wt%, respectively. When acetate and propionate were simultaneously supplied as carbon sources, the engineered A. hydrophila overexpressing β-ketothiolase, acetoacetyl-CoA reductase, and acetyl-CoA synthetase was found able to produce the copolymer of 3-hydroxybutyrate and 3-hydroxyvalerate (PHBV). The recombinant grew to 3.79 g/L cell dry weight (CDW) containing 15.02 wt% PHBV. Our proposed metabolic engineering strategies illustrate the feasibility for producing PHA from acetate by A. hydrophila.

嗜水气单胞菌4AK4通常使用月桂酸作为碳源生产3-羟基丁酸酯和3-羟基己酸酯的共聚物（PHBHHx）。在这项研究中，我们报道的代谢工程嗜水气单用醋酸作为主要碳源4AK4用于生产聚羟基脂肪酸酯（PHA）的。重组嗜水过表达β酮硫解酶和乙酰乙酰辅酶A还原酶可以由乙酸积累聚-3-羟基丁酸酯（PHB），用1.39重量％的聚合物含量。乙酸激酶/磷酸转乙酰酶和乙酰辅酶A合成酶的进一步过表达将PHB含量分别提高到8.75wt％和19.82wt％。当乙酸盐和丙酸盐同时作为碳源供应时，工程嗜水气单胞菌发现过表达β-酮硫醇酶，乙酰乙酰辅酶A还原酶和乙酰辅酶A合成酶能够产生3-羟基丁酸酯和3-羟基戊酸酯（PHBV）的共聚物。重组体生长到含有15.02 wt％PHBV的3.79 g / L细胞干重（CDW）。我们提出的代谢工程策略说明了由亲水曲霉从醋酸盐生产PHA的可行性。