The trend to make conscious decisions that are part of daily household chores, such as using reliable and eco-friendly cleaning products stems from the awareness that people have in promoting the green movement. Consequently, consumers are more discerning about the product features of detergents they use, and therefore detergent manufacturers are always trying to make detergents that not only work fast, but are more environment friendly as well.
Take the dry cleaning industry for instance which uses perchloroethylene that has been around for 50 years. Perchloroethylene or perc as it is referred to isn't good for cleaning wool and silks and more importantly, this substance is toxic if it gets its way into the groundwater, or if a person is overexposed to it. Instead, dry cleaners now use silicone based solvents like Green Earth Cleaning which are less toxic. There are other biodegradable and hypo-allergenic biotech detergents brands like for example Seventh Generation Laundry detergents, Sun & Earth Laundry detergents and the Biokleen brand. All of these newer detergents are free of phosphates and optical brighteners, have no colors, artificial fragrance, and preservatives, and therefore safe if the after- wash water enters streams or soil.
Dr Ohm is credited for making the first enzyme based detergent way back in the early 1900s. Since then, enzymes have been used in making dishwashing detergents, stain removers and for industrial cleaning purposes. Actually very little of enzymes is used in detergent products and cost wise it amounts to just 1% of the product cost but important nevertheless.
Conventional versus enzyme detergents
Conventional detergents emulsify the substrate and that's how they remove dirt etc. When enzyme detergents are used, the substrate that contains fat oil or vegetable matter itself gets degraded. And enzyme detergents don't leave any trace materials after the cleaning process.
When an enzyme detergent degrades a substrate during the cleaning process, the individual enzyme also degrades because of the ensuing catalytic action. Enzyme based detergent uses lower water temperatures to clean, and as compared to conventional detergents quantities required are lesser, and there is no involvement of surfactants and phosphates for the cleaning process. To remove stains, conventional method may require bleaching, but enzyme detergents can handle this as well. The disadvantage with enzyme detergents is they become inactive if temperature goes above 50 degrees Celsius.
Enzymes (essentially proteins made up of amino acids) are essential for metabolic processes, and are made by all living organisms and it is their catalytic activity which differentiates them from other proteins. Enzymes are biodegradable and also very specific in how they are able to do this. That is also the reason why they are safe to the environment as compared to conventional detergents that contain phosphates and other surfactants. Therefore the safety of detergents based on enzymes is assured, because they are not chemical in nature, and also because they don't work on living flora and fauna but only on lifeless organic waste.
The role of enzymes in making detergents
Biotechnology uses fermentation techniques to optimize the living conditions of microorganisms and produces enzymes for industrial use, as naturally occurring enzymes are scarce. After fermentation, the enzymes are isolated and processed further for industrial use. Novo Nordisk and Gist Brocades are the two recognized manufacturers of industrial enzymes of the type used in detergents.
Depending on how effective a particular bacterium is in degrading fat, oil, and vegetable matter, cleaning solutions using enzymes are manufactured. The idea is these enzymes kept in a stabilized state only start working when hydration occurs. Selecting the bacteria that can degrade fat, oil, and vegetable matter is the key to making an enzyme based detergent. The enzyme is then stabilized, and the idea is to make it start working on hydration.
There are 4 broad enzyme groupings namely lipases (can breakdown fats, oils and greases; proteases (can breakdown proteins like blood for instance); amylases (can breakdown carbohydrates; and cellulases (can breakdown cellulose)
Let's examine how each of these enzymes when incorporated in detergents contributes to the washing process.
The use of lipase based enzymes in detergents is fairly recent happening, as the first lipase enzyme for detergents entered the market only in 1987. Lipases obtained from Rhizomucor mehei (fungus source) and Pseudomonas glumae (bacterial source) amongst other sources are capable of removing messy food stains and sweat in the armpit (mainly mix of lipids, starch and proteins) by converting the water insoluble parts in the stain to water soluble parts which usually means converting triglycerides to free fatty acids and glycerol.
Cellulases in detergents involve an enzyme that is especially good for washing cotton fabrics. When cotton fabrics are frequently washed there is a tendency for certain minute fibers to stick out from the cotton texture, causing the fabric to loose its sheen. When cellulases are used it not only removes dirt but makes the colors more vibrant and the texture smooth. Genetically engineered bacterial and fungal strains can be used as for example Bacillus-KM-635 and Humicola isolens DSM1800.
Stains caused by chocolates, cocoa, puddings which are starch oriented stains can be removed by alpha-amylases (mostly used), beta-amylases and isoamylases which work by catalyzing hydrolysis of glycoside linkages in starch. These enzymes belong to the amylase class of enzymes.
Protease enzymes which are probably one of the earliest enzymes to be used in the detergent business are of two types namely, alkaline protease from Bacillus licheniformis, and high alkaline protease from Bacillus alkalophilus and Bacillus lentus. The latter variety is good for cleaning blood stains and other soils caused by proteins.
Other enzyme categories used in the manufacture of detergents are Peroxidases (subclass of general oxidoreductase) and Pullulanases the latter being especially good for stain removal.
In 2008, the European Union announced a June 2015 deadline for chemical suppliers including detergent manufacturers to fall in line with a new set of labeling and packaging requirements, and interestingly under this set of guidelines, concentrated detergents have to be labeled "corrosive". This would mean an even greater role for biotechnology in the making of future detergents.
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