Abstract: The recombinant strains GS115 were acquired,which contained multiple copies of kiwi pectin methylesterase inhibitor gene. The effects of concentration of glycerol,the methanol- sorbitol ratio in the feed medium,initial p H,introduction time and the types of culture medium on the yield of kw PMEI1 were analyzed. The optimal conditions were finally established as follows: BMMY medium,five days fermentation with 3%( v / v)glycerol,1%( v / v) methanol,and p H5.5,at the same time,the mixed feeds of sorbitol solution( 100%,w / v) and methanol( the volume ratio) was 1∶ 1.The highest yield of kw PMEI1 was 700.302 mg / L in the above conditions.