Abstract: A strain for producing γ-decanolactone was obtained by composite mutation (ultraviolet mutation and chemical mutation). After the first ultraviolet mutation, the yield of γ-decanolactone was as 2.5 times as the original strain. But the yield was not stability and didn’t have further increase after more mutations. At last diethyl sulfate stabilized the yield, and it was increased by 2.3 times.

Key words: Yarrowia lipolytica； ultraviolet mutation； chemical mutation； composite mutation； &gamma, -decanolactone；