Modified photosynthetic microorganisms for producing triglycerides
Inventors
Roberts, James • Cross, Fred • Warrener, Paul • Munoz, Ernesto Javier • Lee, Martin Henry • Romari, Khadidja • Kotovic, Kimberly Marie • Hickman, Jason W.
Assignees
Publication Number
US-9029120-B2
Publication Date
2015-05-12
Expiration Date
2029-10-23
Interested in licensing this patent?
MTEC can help explore whether this patent might be available for licensing for your application.
Abstract
This disclosure describes genetically modified photosynthetic microorganisms, including Cyanobacteria, that contain one or more exogenous genes encoding a diacyglycerol acyltransferase, a phosphatidate phosphatase, and/or an acetyl-CoA carboxylase, and which are capable of producing increased amounts of fatty acids and/or synthesizing triglycerides.
Core Innovation
The invention relates to genetically modified photosynthetic microorganisms, particularly Cyanobacteria, that are engineered to produce increased amounts of fatty acids and/or synthesize triglycerides. This is accomplished by introducing one or more exogenous genes encoding enzymes such as diacylglycerol acyltransferase (DGAT), phosphatidate phosphatase, and/or acetyl-CoA carboxylase into the microorganisms. These enzymes catalyze crucial steps in triglyceride and fatty acid biosynthesis, thus enabling or enhancing triglyceride production in organisms that do not naturally perform this function.
Conventional sources of triglycerides for biofuel production, like algae, are limited due to their difficulty in genetic manipulation and lower triglyceride yields under culture conditions. Cyanobacteria, while genetically accessible and capable of photosynthesis similar to algae, lack the necessary enzymes for triglyceride synthesis and so do not naturally accumulate triglycerides as energy storage molecules. The invention addresses this problem by engineering Cyanobacteria to express key biosynthetic enzymes, thereby enabling the biosynthesis and accumulation of triglycerides.
The invention includes methods of producing triglycerides and increasing fatty acid production by introducing exogenous genes encoding DGAT, phosphatidate phosphatase, and/or acetyl-CoA carboxylase into photosynthetic microorganisms. This genetic modification allows for the conversion of naturally occurring fatty acids into triglycerides and increases overall lipid content in the engineered microorganisms. The technology is applicable to various genetically manipulable Cyanobacteria, including both freshwater and salt tolerant strains.
Claims Coverage
There are three main inventive features in the independent claims of this patent.
Modified cyanobacterium comprising an exogenous DGAT that uses acyl-ACP as a substrate
A modified Cyanobacterium is constructed to contain an exogenous polynucleotide encoding a diacylglycerol acyltransferase (DGAT) that uses acyl-ACP as a substrate. As a result, the modified Cyanobacterium is capable of producing a triglyceride, a wax ester, or both. - The DGAT can be from a prokaryotic source, such as Acinetobacter, Streptomyces, or Alcanivorax. - The Cyanobacterium can be, but is not limited to, Synechococcus elongatus PCC 7942, a salt tolerant variant thereof, Synechococcus PCC 7002, or Synechocystis PCC 6803. - The Cyanobacterium may be salt tolerant.
Method for producing triglyceride, wax ester, or both by culturing the modified cyanobacterium
A method comprising culturing the modified Cyanobacterium (as described above) to produce a triglyceride, a wax ester, or both. - The method is broadly applicable and encompasses using the engineered strains mentioned, including salt tolerant variants and specified Cyanobacterium strains. - The DGAT expressed can be from Acinetobacter, Streptomyces, or Alcanivorax.
Method for making a modified cyanobacterium by introducing an exogenous DGAT that uses acyl-ACP as a substrate
A method for making a modified Cyanobacterium by introducing into a Cyanobacterium an exogenous polynucleotide encoding a DGAT that uses acyl-ACP as a substrate, resulting in the production of a triglyceride, a wax ester, or both. - This inventive feature emphasizes the genetic modification step and the functional outcome in terms of triglyceride or wax ester biosynthesis. - The method includes using DGAT from Acinetobacter, Streptomyces, or Alcanivorax, and may apply to any of the specified Cyanobacterium strains, including salt tolerant variants.
The claims are centered on the construction and use of genetically modified Cyanobacteria expressing a non-native DGAT that utilizes acyl-ACP, leading to the production of triglycerides or wax esters through specific culturing, and outline methods to create such modified organisms.
Stated Advantages
The modified Cyanobacteria can be genetically manipulated more readily than algae, allowing controlled and efficient triglyceride production.
Triglyceride-producing Cyanobacteria can serve as a sustainable feedstock for biofuels and specialty chemicals using only sunlight, water, CO2, and minimal nutrients.
Some engineered strains are tolerant to brackish or salt water, enabling production in non-freshwater environments and reducing reliance on freshwater resources.
Genetically engineered Cyanobacteria allow for increased fatty acid production, boosting the precursor supply for triglyceride synthesis.
Documented Applications
Use of engineered Cyanobacteria as a feedstock for biofuel production, specifically biodiesel.
Production of specialty chemicals such as glycerin as a by-product of triglyceride-derived biofuel processes.
Interested in licensing this patent?