Immobilization of lipase on woolen fabrics: enhanced effectiveness in stain removal

The aim of this research was to examine the effectiveness of an enzyme in enhancing the cleaning effectiveness of woolen fabric without addition of any detergent. As a model enzyme, lipase from Pseudomonas fluoresces was immobilized onto a woolen cloth using a unique protocol that involved: chlorination of the wool, adsorbing a polyethyleneimine (PEI) spacer, adsorbing, and cross-linking with glutaraldehyde (GA) followed by adsorption of the lipase. It was determined that for this protocol, the immobilized activity was dependent on the GA solution pH and not on its concentration. The cloth exhibited excellent oily stain removal ability: after being stained with olive oil and stored for 1 day in air at room temperature, the oily stain could be easily removed by 0.05 M pH 8.5 Tris buffer without any detergent addition. This enhanced cleaning was stable also over a period of one month. The activity of the cloth (based on activity assay) dropped considerably over just 15 days storage in air. This therefore likely indicates that the enhanced cleaning seen over an extended storage period may not require as high an enzyme activity. The activity of the immobilized lipase was also very stable when stored under near ideal conditions: when the immobilized cloth was stored in 0.05 M Tris buffer (pH 8.5) for more than 80 days in a refrigerator, more than 80% of the lipase activity remained. Overall, results indicate that this immobilization protocol is a promising step towards producing a woolen fabric with enhanced cleaning properties.