Biodiesel production catalyzed by free lipase has been drawing attention for its lower cost and faster reaction rate compared to immobilized lipase.It has been found that free lipase NS81006 could efficiently catalyze the methanolysis and ethanolysis of renewable oils for biodiesel production in a biphasic water–oil system and a certain amount of water is demonstrated to be necessary for the catalytic process.However,there was no research on what the influence of water content on the catalytic process.In this paper,the effect of water content on liquid lipase NS81006-mediated methanolysis and ethanolysis for biodiesel production was explored respectively for the first time.The results showed that with water content ranging from 3%to 10%(based on oil weight),there was no significant difference in the final biodiesel yield either in NS81006-mediated methanolysis or ethanolysis process.