title: Integration of sewage sludge digestion with advanced biofuel synthesis.
abstract: 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.
authors: Department of Biosystems and Agricultural Engineering, Michigan State University, East Lansing, MI 48824, USA.
authors: Zhiguo
authors: Z
authors: Liu
authors: Zhenhua
authors: Z
authors: Ruan
authors: Yi
authors: Y
authors: Xiao
authors: Yu
authors: Y
authors: Yi
authors: Yinjie J
authors: YJ
authors: Tang
authors: Wei
authors: W
authors: Liao
authors: Yan
authors: Y
authors: Liu
mesh_terms: D000085:Acetates / Q000378:metabolism; D000693:Anaerobiosis; D001426:Bacterial Proteins / Q000378:metabolism; D056804:Biofuels; D001709:Biotechnology / Q000379:methods*; D004063:Digestion; D004926:Escherichia coli / Q000378:metabolism*; D005227:Fatty Acids / Q000096:biosynthesis; D020094:Mortierella / Q000378:metabolism*; D012097:Repressor Proteins / Q000378:metabolism; D012722:Sewage / Q000382:microbiology*
chemical_list: D000085:Acetates; D001426:Bacterial Proteins; D056804:Biofuels; C057119:FadR protein, Bacteria; D005227:Fatty Acids; D012097:Repressor Proteins; D012722:Sewage