This Small Business Innovation Research (SBIR) Phase I project aims to evaluate the use of a marine organism for production of the polyunsaturated fatty acid (PUFA), docosahexaenoic acid (DHA). DHA is important for maintaining good health and is in serious supply shortage worldwide. Metabolic engineering will be used to increase DHA production in Moritella marina, which naturally produces DHA. This will be accomplished by deletion of competing metabolic pathways to increase expression of the DHA-producing pathway. The goal is to increase production such that the overall DHA titer is 1.0 g/L. This work also will provide insight into control of central metabolic flux and sensing and control of fatty acid content and production. Thus, the intellectual merit of this work extends to a variety of metabolic products.
The broader impact/commercial impact of this project is the development of an alternative production system for DHA, a sustainable and safe nutraceutical that is in serious supply shortage worldwide. Data suggest that omega-3 fatty acids, such as DHA, play important roles in enhancing heart health, brain health, child and infant development and preventing various chronic diseases, such as rheumatoid arthritis, obesity and type-2 diabetes. It is recommended that the general public consume at least 100-1000 mg of PUFA daily; the current primary source for DHA is from cold water fish, which cannot meet global demand. The commercial goal is to biomanufacture DHA, and then market a DHA-enriched oil to nutritional supplement and food manufacturers to meet the growing demand for this product.
The goal of this Small Business Innovation Research (SBIR) Phase I project was to evaluate the feasibility of metabolic engineering of a marine bacterium, Moritella marina MP-1, in order to increase the amount of docosahexaenoic acid (DHA) produced. Polyunsaturated fatty acids (PUFA), such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) have beneficial effects on human health through their effect on membrane fluidity and contribute to many positive aspects of health, such as fetal development and prevention of cancer and obesity. These PUFAs are commonly found in fish oils from fish such as salmon. However, this increasing demand is complicated by the fact that even the current demand cannot be sustained with fish-derived PUFAs. The objective of this proposal was to establish the feasibility of metabolic engineering as a strategy to increase the amount of DHA produced by this marine bacterium. We aimed to establish this feasibility by (i) removing the gene responsible for production of acetate, a competing metabolic product and (ii) increasing DHA production by increasing expression of DHA-producing genes. This work could also provide important information about which genes are responsible for controlling DHA production. The broader impacts/commercial potential of this SBIR Phase I project were to increase production of a sustainable and safe nutraceutical that is in serious supply shortage worldwide. The current primary supply is from cold water fish and cannot meet this global demand. It is recommended that the general public consume at least 100-1000 mg of PUFAs daily. The growth potential is significant based on the growing body of scientific evidence demonstrating that people of all ages benefit from an adequate supply of DHA omega-3 in their diets. Data suggest that omega-3 fatty acids play important roles in enhancing heart health, brain health, and child and infant development, and preventing various chronic diseases such as rheumatoid arthritis, obesity, and type 2 diabetes. Our original plan for objective one was to use the same gene deletion strategy that we had previously used to remove the gene responsible for production of acetate, a competing metabolic product. However, this strategy proved to be more difficult than anticipated. Five additional strategy modifications were tried but were unsuccessful. The second objective was to increase DHA production by increasing expression of DHA-producing genes. We found that our metabolic engineering modifications had a severe impact on the marine bacteria's growth and had impact on fatty acid composition. The innovative outcome of this work was not achieved as we were unable to metabolically engineer the marine bacteria strain to increased DHA production. The key outcome of this work was the decision that metabolic engineering of M. marina MP-1 for increased DHA production is, at this time, beyond the technical skills available to our research group. We are not planning on pursuing this project further at this current time.
