Lipase-catalyzed biodiesel production from soybean oil deodorizer distillate with absorbent present in tert-butanol system

Lipase-catalyzed alcoholysis of soybean oil deodorizer distillate (SODD) for biodiesel production was studied. During this system both free fatty acids and glycerides could be converted to biodiesel simultaneously. tert-Butanol has been adopted as the reaction medium, in which both the negative effects caused by excessive methanol and by-product glycerol could be eliminated completely. There was no obvious loss in lipase activity even after being repeatedly used for 120 cycles. Fine-pored silica gel and 3 Å molecular were found to be effective to control by-product water concentration and much higher biodiesel yield could be achieved with those adsorbents present in the reaction system. The highest biodiesel yield of 97% could be achieved with 3 Å molecular sieve as the adsorbent.