Metabolic engineering of Pichia pastoris to produce ricinoleic acid, a hydroxy fatty acid of industrial importance.
Ricinoleic acid (12-hydroxyoctadec-cis-9-enoic acid) has many specialized uses in bioproduct industries, while castor bean is currently the only commercial source for the fatty acid. This report describes metabolic engineering of a microbial system (Pichia pastoris) to produce ricinoleic acid using a "push" (synthesis) and "pull" (assembly) strategy. CpFAH, a fatty acid hydroxylase from Claviceps purpurea, was used for synthesis of ricinoleic acid, and CpDGAT1, a diacylglycerol acyl transferase for the triacylglycerol synthesis from the same species, was used for assembly of the fatty acid. Coexpression of CpFAH and CpDGAT1 produced higher lipid contents and ricinoleic acid levels than expression of CpFAH alone. Coexpression in a mutant haploid strain defective in the Δ12 desaturase activity resulted in a higher level of ricinoleic acid than that in the diploid strain. Intriguingly, the ricinoleic acid produced was mainly distributed in the neutral lipid fractions, particularly the free fatty acid form, but with little in the polar lipids. This work demonstrates the effectiveness of the metabolic engineering strategy and excellent capacity of the microbial system for production of ricinoleic acid as an alternative to plant sources for industrial uses.
Department of Food & Bioproduct Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, S7N 5A8, Canada National Research Council Canada, Saskatoon, Saskatchewan, S7N 0W9, Canada.
Dauenpen
D
Meesapyodsuk
Department of Food & Bioproduct Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, S7N 5A8, Canada.
Yan
Y
Chen
Department of Food & Bioproduct Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, S7N 5A8, Canada.
Siew Hon
SH
Ng
Department of Food & Bioproduct Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, S7N 5A8, Canada.
Jianan
J
Chen
Department of Food & Bioproduct Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, S7N 5A8, Canada National Research Council Canada, Saskatoon, Saskatchewan, S7N 0W9, Canada.
Xiao
X
Qiu
D019149:Bioreactors; D002967:Claviceps / Q000201:enzymology / Q000235:genetics; D051048:Diacylglycerol O-Acyltransferase / Q000096:biosynthesis / Q000235:genetics; D044943:Fatty Acid Desaturases / Q000096:biosynthesis / Q000235:genetics; D005656:Fungal Proteins / Q000096:biosynthesis / Q000235:genetics; D050356:Lipid Metabolism; D060847:Metabolic Engineering; D010802:Phylogeny; D010843:Pichia / Q000235:genetics / Q000378:metabolism*; D012277:Ricinoleic Acids / Q000378:metabolism*
D005656:Fungal Proteins; D012277:Ricinoleic Acids; D044943:Fatty Acid Desaturases; D051048:Diacylglycerol O-Acyltransferase; C030521:ricinoleic acid
Claviceps purpurea; diacylglycerol acyltransferase; fatty acid hydroxylase