Fatty soil cleaning with ozone and lipases. A way to develop more environmentally friendly washing processes
In this work we review the state-of-the-art of the use of lipases and ozone in washing processes to remove fatty soils. Although lipases have not yet reached the goal of replacing surfactants in commercial formulations, according to our own results it seems possible, provided that the washing conditions are carefully chosen to optimize lipase performance. Additionally, intensive research is being conducted by both companies and governmental institutions in order to develop more efficient lipases to be used as detergent additives. As regards the use of ozone it has been demonstrated that fat ozonation in the presence of water generates surface active molecules, such as free fatty acids, which may contribute to the removal of fatty stains.
Fatty soils are a common target of domestic and industrial cleaning operations, particularly in the food industry. Due to the difficulty of cleaning this kind of soils, strong conditions, such as high alkali and/or surfactant concentrations as well as elevated temperatures, are usually employed (1). This implies high energy consumption and the generation of highly polluted wastewaters.
The partial replacement of surfactants and alkalis by lipases is among the available options to reduce the dosage of chemicals needed to achieve good cleaning performance on greasy stains, even at moderately low temperatures. Lipases can hydrolyse triglycerides into more hydrophilic and thus easier to remove substances, such as free fatty acids, diglycerides and monoglycerides (2). Additionally, the molecules released by the action of lipases are themselves surface-active, which also helps the removal of fatty soils (3).
Lipolase was the first lipase specifically conceived to be used as a detergent additive. It was developed and launched by Novozymes in 1988 (4). Since then Novozymes have marketed several variants of their original lipase, such ...