Modified photosynthetic microorganisms for producing lipids

Abstract

This disclosure describes genetically modified photosynthetic microorganisms, e.g., Cyanobacteria, that overexpress an acyl carrier protein (ACP), an acyl-ACP synthase (Aas), or both, optionally in combination with one or more overexpressed or exogenous lipid biosynthesis proteins, and/or one or more overexpressed or exogenous glycogen breakdown proteins. Exemplary biosynthesis proteins include diacyglycerol acyltransferases, thioesterases, phosphatidate phosphatases, phospholipases, triacylglycerol (TAG) hydrolases, fatty acyl-CoA synthetases, and/or acetyl-CoA carboxylases, including combinations thereof. Also included are photosynthetic microorganisms comprising mutations or deletions in a glycogen biosynthesis or storage pathway, which accumulate a reduced amount of glycogen under reduced nitrogen conditions as compared to a wild type photosynthetic microorganism. The modified photosynthetic microorganisms provided herein are capable of producing increased amounts of lipids such as fatty acids and/or synthesizing triglycerides.