Engineering lipid overproduction in the oleaginous yeast Yarrowia lipolytica.
Conversion of carbohydrates to lipids at high yield and productivity is essential for cost-effective production of renewable biodiesel. Although some microorganisms can convert sugars to oils, conversion yields and rates are typically low due primarily to allosteric inhibition of the lipid biosynthetic pathway by saturated fatty acids. By reverse engineering the mammalian cellular obese phenotypes, we identified the delta-9 stearoyl-CoA desaturase (SCD) as a rate limiting step and target for the metabolic engineering of the lipid synthesis pathway in Yarrowia lipolytica. Simultaneous overexpression of SCD, Acetyl-CoA carboxylase (ACC1), and Diacylglyceride acyl-transferase (DGA1) in Y. lipolytica yielded an engineered strain exhibiting highly desirable phenotypes of fast cell growth and lipid overproduction including high carbon to lipid conversion yield (84.7% of theoretical maximal yield), high lipid titers (~55g/L), enhanced tolerance to glucose and cellulose-derived sugars. Moreover, the engineered strain featured a three-fold growth advantage over the wild type strain. As a result, a maximal lipid productivity of ~1g/L/h is obtained during the stationary phase. Furthermore, we showed that the engineered yeast required cytoskeleton remodeling in eliciting the obesity phenotype. Altogether, our work describes the development of a microbial catalyst with the highest reported lipid yield, titer and productivity to date. This is an important step towards the development of an efficient and cost-effective process for biodiesel production from renewable resources.
Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, United States.
Kangjian
K
Qiao
Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, United States.
Syed Hussain
SH
Imam Abidi
Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, United States.
Hongjuan
H
Liu
Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, United States.
Haoran
H
Zhang
Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, United States.
Sagar
S
Chakraborty
Whitehead Institute for Biomedical Research, W.M. Keck Imaging Facility, 9 Cambridge Center, Room 447, Cambridge, MA 02142, United States.
Nicki
N
Watson
Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, United States.
Parayil
P
Kumaran Ajikumar
Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, United States. Electronic address: gregstep@mit.edu.
Gregory
G
Stephanopoulos
D000103:Acetyl-CoA Carboxylase / Q000235:genetics / Q000378:metabolism; D051048:Diacylglycerol O-Acyltransferase / Q000235:genetics / Q000378:metabolism; D044943:Fatty Acid Desaturases / Q000235:genetics / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D008055:Lipids / Q000096:biosynthesis / Q000235:genetics; D060847:Metabolic Engineering; D013230:Stearoyl-CoA Desaturase; D025062:Yarrowia / Q000235:genetics / Q000378:metabolism
D005656:Fungal Proteins; D008055:Lipids; D044943:Fatty Acid Desaturases; D013230:Stearoyl-CoA Desaturase; C029627:delta-9 fatty acid desaturase; D051048:Diacylglycerol O-Acyltransferase; D000103:Acetyl-CoA Carboxylase
Autophagy; Biodiesel; Metabolic engineering; Triacylglycerol