Project Number: 6435-41000-087-00
Project Type: Appropriated

Start Date: Aug 05, 2004
End Date: Aug 04, 2009

Objective:
Identify enzymes involved in the biosynthesis of tung oil. Develop a microbial expression system for bioconversion of low-cost oils into tung-like drying oils. Optimize activity of tung enzymes in microbial bioconversion system.

Approach:
Genes encoding the enzymes for tung oil biosynthesis will be identified by two complementary methods: 1. A homology-based approach in which tung genes are identified by their similarity to previously identified, oil-related genes characterized in other plant species. Gene-specific probes will be designed to screen a tung seed cDNA library by either PCR or traditional library screening. 2. A genomics approach in which all genes expressed during tung oil biosynthesis are first identified, then microarray or mass sequencing projects are used to identify oil related genes by bioinformatics methods. A microbial expression system tailored for the bioconversion of low-cost oils into tung-like drying oils will be generated by engineering common baker's yeast to secrete lipases into the growth media. The yeast cells will also be modified to co-express two or more tung enzymes to increase the conversion rate of exogenously acquired oils into tung-like drying oils. The activity of lipid-modifying enzymes will be optimized by studying the relationship between protein half-life and enzyme activity. Factors that increase or decrease enzyme activity will be identified and the information utilized to improve enzyme performance in yeast cells.