Enzyme compatibility with nonionic surfactants in liquid laundry detergents
Chemical structural influence of commonly used nonionic surfactants in laundry detergent on enzymatic activity was described. Compatibility of lipase, protease and amylase was systematically tested on a broad range of linear and branched FAE (fatty alcohol ethoxylates) with varying chain length and ethoxylation degree and the respective FAMEE (fatty acid methyl ester ethoxylates) at different concentrations. Irrespective of enzyme types, their activity generally decreased with increasing surfactant concentration. Lipase, however, reacted the most sensitively and only small amount was tolerated before a complete loss of activity was observed. With respect to structural dependency, lipase and protease showed good activity in presence of surfactants with shorter chain length and smaller ethoxylation degree, whereas amylase was significantly less influenced by the differing structures. These results can aid product developers meet a better pre-selection during formulation.
The use of enzymes as a part of laundry detergent exist since the 60s, initially in soaking powders for removing proteinaceous stains. Nowadays, employing a cocktail of enzymes have become a norm: lipase (lipid degrading), protease (protein degrading) and amylase (starch degrading) are aimed to tackle stains commonly found on the fabric, whereas cellulase (cellulose degrading) and mannanase (rheology modifiers degrading) are formulated to decelerate ageing process of garments (1, 2). Incorporation of these types of enzymes in cleaning formulations, such as laundry detergent and automatic dishwashing, can enhance the removal of wide spectrum of soils present on fabrics and hard surfaces. They help to increase the detergency especially at low temperatures. This, in parallel to the practice to save water and energy, is a tendency towards sustainability we increasingly observe these days. Moreover, enzyme incorporation contributes also to compaction as less amount of main actives are necessary to achieve the same or an enhanced cleaning performance.
In 1959, a German chemist, Herbert Sinner, described “Sinner-circle” that defined the ...