Department of Biosystems and Agricultural Engineering, Michigan State University, East Lansing, MI 48824, USA.
Bioresour Technol. 2013 Mar;132:166-70. doi: 10.1016/j.biortech.2013.01.017. Epub 2013 Jan 16.
Sewage sludge rich in carbohydrates and other nutrients could be a good feedstock for fuel/chemical production. In this study, fungal and engineered bacterial cultivations were integrated with a modified anaerobic digestion to accumulate fatty acids on sewage sludge. The anaerobic digestion was first adjusted to enable acetogenic bacteria to accumulate acetate. A fungus (Mortierella isabellina) and an engineered bacterium (Escherichia coli created by optimizing acetate utilization and fatty acid biosynthesis as well as overexpressing a regulatory transcription factor fadR) were then cultured on the acetate solution to accumulate fatty acids. The engineered bacterium had higher fatty acid yield and titer than the fungus. Both medium- and long-chain fatty acids (C12:0-C18:0) were produced by the engineered bacterium, while the fungus mainly synthesized long-chain fatty acids (C16:0-C18:3). This study demonstrated a potential path that combines fungus or engineered bacterium with anaerobic digestion to achieve simultaneous organic waste treatment and advanced biofuel production.
富含碳水化合物和其他营养物质的污水污泥可以成为生产燃料/化学品的优质原料。在这项研究中，真菌和工程细菌的培养与改良的厌氧消化相结合，以在污水污泥上积累脂肪酸。首先调整厌氧消化，以使产乙酸菌积累乙酸。然后，在乙酸溶液上培养真菌（Isabellina 木霉）和工程细菌（通过优化乙酸利用和脂肪酸生物合成以及过表达调节转录因子 fadR 而创建的大肠杆菌）以积累脂肪酸。与真菌相比，工程细菌具有更高的脂肪酸产量和浓度。工程细菌产生中链和长链脂肪酸（C12:0-C18:0），而真菌主要合成长链脂肪酸（C16:0-C18:3）。这项研究展示了一种潜在途径，即将真菌或工程细菌与厌氧消化相结合，以实现有机废物的同时处理和先进生物燃料的生产。
