Mechanism of removal of immobilized triacylglycerol by lipolytic enzymes in a sequential laundry wash process

Although the contribution of lipolytic enzymes to fatty soil removal after repeated laundry wash cycles has been established the benefit of lipolytic enzymes in detergent products after a single wash is marginal. In order to improve fatty soil removal with the help of lipolytic enzymes during the main wash cycle, a two-step sequential wash system has been set up. Triglyceride oil, immobilized on a testcloth, is hydrolyzed by the lipolytic enzyme during the first incubation. In a subsequent incubation, a detergent product was added to remove the fatty soil. In this sequential wash system, the commercially available Lipolase(TM) did nor attribute to enhanced soil removal as water insoluble calcium soaps were formed. The use of a calcium-independent lipolytic enzyme, cutinase, resulted in a significant increased soil removal. During the first incubation at pH 9, the soil was hydrolyzed for 65% within 30 min but only 20% of the products was removed. An increase in the pH to pH > 10.5 was sufficient to remove the majority of the hydrolysis products to the water phase. No detergent product needed to be added It is concluded that the enzyme benefit in the sequential wash system could be attributed to the partitioning of hydrolysis products over the water and oil phase. It is shown that the benefit of cutinase in a nonsequential wash mainly could be attributed to its calcium independency and the solubilization of hydrolysis products. (C) 1998 Elsevier Science Inc.