A biological detergent is a laundry detergent that contains enzymes harvested from micro-organisms such as bacteria adapted to live in hot springs. The description is commonly used in the United Kingdom, where other washing detergents are described as "non-biological" (or bio and "non-bio"). Most manufacturers of biological detergents also produce non-biological ones.
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Function
Biological detergents clean in the same way as non-biological ones with additional effects from the enzymes, whose purpose is to break down protein, starches and fat in dirt and stains on clothing to be laundered, for example food stains, sweat and mud. Tests by the Consumers' Association in the UK published in their Which? magazine rated the cleaning performance of washing powders based on stain removal, whiteness, and colour fading. It was found that the performance of various makes of biological powders ranged from 58% to 81%, and non-biological powders scored from 41% to 70%. The enzymes in biological detergents enable effective cleaning at lower temperatures than required by normal detergents, but are denatured at higher temperatures—about 50 °C is recommended. A biological detergent can contain α-amylase, a cellulase, a protease and a lipase.
Controversy
It has been said that some people may be allergic to the enzymes which can be transferred to the skin when wet clothes that have just been cleaned with biological detergents are touched. The enzymes then restart the breakdown reaction on the skin—particularly protease. A study by a manufacturer found that "The biological products did not produce more irritation than the non-biological products, confirming that the addition of enzymes to a detergent formulation does not result in an increase in the skin irritation caused byprofile [sic] of the detergent." A study by hospital dermatologists published in the British Journal of Dermatology found that "ultimately, the balance of all the enzymes in laundry detergents are not a cause of either skin irritation or skin allergy ... the supposed adverse effects of enzymes on the skin seem to be a consequence of mythology". Three of the authors of the paper had conflicts of interest relating to Unilever, which they declared.