Laundry bleach enzymes

In general, laundry aids contribute to the effectiveness of laundry detergents and provide unique functions. Laundry aids include builders, bleaches, enzymes, fabric softeners, and optical whiteners. 

Other examples of concentrated laundry liquids have been described in the literature [53]. These might be called nonaqueous or low-water formulations. They may contain nonionic and anionic surfactants, inorganic builders, enzyme and bleach additives, and an organic solvent such as a low mole AE [54]. Surfactant levels may range from 30% up to 80%. In some cases, the builder salts are dispersed as solid particles in the non-aqueous phase [55]. 

All proteolytic enzymes described are fairly non-specific serine endoproteases, cleaving peptide chains preferentially at the carboxyl side of hydrophobic amino acid residues. The enzymes convert their substrates into small, readily soluble fragments which can be removed easily from fabrics. Only serine protease can be used in detergent formulations, as thiol proteases such as papain would be oxidized by the bleaching agents, acidic proteases are not active at common laundry conditions, and metalloproteases such as thermolysin would lose their metal cofactors because of complexation with the water-softening agents or hydroxyl ions. 

An example of this kind of work involves the enzyme subtilisin, frequently used as an additive in laundry detergents because it attacks the proteins that soil clothing. The problem, however, is that subtilisin is easily destroyed by bleaches with which a detergent is often used. Research showed that subtilisin is sensitive to bleach because a single amino acid in its primary structure—a methionine at position 22—is destroyed by bleach. By replacing this methionine with an amino acid that is not sensitive to attack by bleach, then, researchers were able to synthesize a new form of subtilisin that did not degrade in the presence of bleach for use in laundry detergents. 

The industrial use of rDNA technology includes the production of bleach-resistant enzymes that are used in laundry detergents to degrade... 

Laundry detergents vary widely in compositions and particular uses and can be partial-built, complete-built, prewash, main wash, bleaching, or enzyme detergents. The liquid detergents can be structured or unstructured. 

Laundry detergents are generally composed of linear alkylbenzene sulfonates (LAS) and alcohol ethoxylates (AE) plus enzymes, builders, and possibly a bleach. The major surfactants are well known for their particulate- and oil-re-moving properties, respectively, plus low cost and safety. 

Traditionally, powdered and liqnid laundry detergents contained linear alkyl benzene sulfonates, ether sulfates, and alcohol ethoxylates as surfactants, along with builders, enzymes, polymers, and possibly bleaches as additional active ingredients. These formulations dealt weU with different types of dirt and stains under a variety of water conditions. 

Laundry presoaks typically contain an enzyme for breaking up protein soils a builder such as sodium tripolyphosphate, sodium carbonate, or sodium silicate and, usually, a surfactant. Bleach or optical brighteners may also be added. 

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