Genetically engineer an industrially-useful fungal lipase

The high cost of enzymes is one reason that lipases are not used for processing fats and oils. The fungus Rhizopus delemar produces a lipase that has a high degree of specificity for the hydrolysis and resynthesis of the primary ester bonds of triglycerides. However, production of this lipase by the fungus is low, and isolating the enzyme is difficult.

To overcome these problems, USDA/ARS researchers (Eastern Regional Research Center, 600 E. Mermaid Lane, Wyndmoor, PA 19038) have cloned the lipase gene and transferred it into the bacterium E. coli. They've optimized production of the lipase by the cloned gene in this strain of E. coli. The modified organism is serving as a readily-grown source of the enzyme.

The lipase shows a high degree of positional selectivity for the primary ester bonds of triglycerides in both the hydrolytic and synthetic modes of action. It is active in aqueous and organic solvents and can be used for both the hydrolysis and restructuring of fats and oils, and the generation of flavor and essence compounds.

Preparations of the lipase from this organism contain no other fungal proteins or lipases. In subsequent work, the production of the enzyme by the cloned gene has been increased more than 100-fold. In addition, a derivative of the enzyme has been produced that is substantially more heat-resistant than the original fungal lipase. Current studies are directed at the mutation of the cloned gene to produce variants of the lipase with improved properties.

The technology is available for licensing. In working with an industrial partner, the researchers would provide samples of the enzymes for testing in reaction schemes. They'd also collaborate on the directed mutagenesis of the gene to produce a modified lipase; provide microbial strains bearing the cloned gene to be used in lipase production within the partner's facilities; assist in lipase isolation and purification; and collaborate on the application of these enzymes as industrial catalysts.

The ARS lipase group is an established multidisciplinary team with 10 years of experience in the biochemistry, molecular biology and applied enzymology of lipases. The group has developed specialized skills that maximize the probability of success in the design and development of lipases and lipase-catalyzed reactions.

Patent. 5,219,753-Genetically engineered microorganisms containing a gene segment coding for a lipase from Rhizopus delemar. Issued June 15, 1993. The patent covers a lipase purified from Rhizopus delemar and its production. Inventors: Thomas Berka and Michael Haas. Assigned to: USDA.

Further information. Michael Haas; phone: [phone]; fax: [phone]; email: [e-mail]. Licensing: Diana Tucker; phone: [phone]; fax: [phone]; email: [e-mail].