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Title: Fundamental studies to design novel enzyme technologies for home and personal care applications
Author: Lilley, R. E.
Awarding Body: University College London (University of London)
Current Institution: University College London (University of London)
Date of Award: 2011
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Abstract:
Enzymes are used in home and personal care applications for the removal of dirt and grease from surfaces. Of these, laundry cleaning utilizes the most enzymes. Technological innovations in the application of enzymes may provide solutions to challenging substrate-surface problems. Poor stability in detergents and high non-specific binding to cloth fabric suggests there is a need for improved lipase technologies. Metagenome analysis of soil bacteria is a successful approach to identifying novel enzymes with improved properties. Novel lipases were found to have improved performance over standard commercial lipases, as well as reduced non-specific binding. Literature suggested that immobilization of lipases on hydrophobic surfaces results in hyperactivation and improved thermostability. Lipases immobilized on a highly hydrophobic surface of fungal hydrophobins resulted in hyperactivation towards large mono- and triglycerides. A matrix of plant polysaccharides, proteins and lipids immobilized on cloth fabric was characterized. Various enzymes active towards components of the cell wall matrix were suggested for its degradation. Subtilases hydrolyzed chlorophyll binding proteins, releasing most chlorophyll. Pectin lyase released chlorophyll, supporting a mechanism whereby polysaccharide matrix loosening enables the release of chlorophyll. Chlorophyllase was ineffective in reducing the redeposition of chlorophyll on cloth fabric. The washed plant matrix was found to contain residual hemicellulose, therefore xylanases and accessory hemicellulases were hypothesized and tested as effective solutions. Calcium ions hinder the protease wash removal of proteinaceous matrices such as the immobilized plant matrix. The recent move to concentrated liquid detergents leaves little formulation space for metal ion chelators, therefore there is a need for improved protease technologies. Calcium ions were found to significantly reduce the susceptibility of bovine serum albumin and milk proteins to proteolytic degradation. Alternative protease specificities were hypothesized to provide a solution to this problem. A calcium-dependent metalloprotease (thermolysin) outperformed standard commercial subtilase in an environment high in calcium ions.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.625536  DOI: Not available
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