Kalscheuer Rainer, Stöveken Tim, Luftmann Heinrich, Malkus Ursula, Reichelt Rudolf, Steinbüchel Alexander
Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität, Corrensstrasse 3, D-48149 Münster, Germany.
Appl Environ Microbiol. 2006 Feb;72(2):1373-9. doi: 10.1128/AEM.72.2.1373-1379.2006.
Wax esters are esters of long-chain fatty acids and long-chain fatty alcohols which are of considerable commercial importance and are produced on a scale of 3 million tons per year. The oil from the jojoba plant (Simmondsia chinensis) is the main biological source of wax esters. Although it has a multitude of potential applications, the use of jojoba oil is restricted, due to its high price. In this study, we describe the establishment of heterologous wax ester biosynthesis in a recombinant Escherichia coli strain by coexpression of a fatty alcohol-producing bifunctional acyl-coenzyme A reductase from the jojoba plant and a bacterial wax ester synthase from Acinetobacter baylyi strain ADP1, catalyzing the esterification of fatty alcohols and coenzyme A thioesters of fatty acids. In the presence of oleate, jojoba oil-like wax esters such as palmityl oleate, palmityl palmitoleate, and oleyl oleate were produced, amounting to up to ca. 1% of the cellular dry weight. In addition to wax esters, fatty acid butyl esters were unexpectedly observed in the presence of oleate. The latter could be attributed to solvent residues of 1-butanol present in the medium component, Bacto tryptone. Neutral lipids produced in recombinant E. coli were accumulated as intracytoplasmic inclusions, demonstrating that the formation and structural integrity of bacterial lipid bodies do not require specific structural proteins. This is the first report on substantial biosynthesis and accumulation of neutral lipids in E. coli, which might open new perspectives for the biotechnological production of cheap jojoba oil equivalents from inexpensive resources employing recombinant microorganisms.
蜡酯是长链脂肪酸和长链脂肪醇形成的酯，具有相当重要的商业价值，年产量达300万吨。荷荷巴植物（西蒙得木）的油是蜡酯的主要生物来源。尽管荷荷巴油有众多潜在应用，但因其价格高昂，其使用受到限制。在本研究中，我们描述了通过共表达来自荷荷巴植物的产脂肪醇双功能酰基辅酶A还原酶和来自拜氏不动杆菌ADP1菌株的细菌蜡酯合酶，在重组大肠杆菌菌株中建立异源蜡酯生物合成的过程，这两种酶催化脂肪醇与脂肪酸辅酶A硫酯的酯化反应。在油酸存在的情况下，产生了类似荷荷巴油的蜡酯，如棕榈油酸酯、棕榈油烯酸酯和油醇油酸酯，产量高达细胞干重的约1%。除蜡酯外，在油酸存在下意外观察到了脂肪酸丁酯。后者可归因于培养基成分胰蛋白胨中存在的1 - 丁醇溶剂残留。重组大肠杆菌中产生的中性脂质以胞质内含物的形式积累，表明细菌脂质体的形成和结构完整性不需要特定的结构蛋白。这是关于大肠杆菌中大量生物合成和积累中性脂质的首次报道，这可能为利用重组微生物从廉价资源生物技术生产廉价的荷荷巴油等效物开辟新的前景。
