Imagine you’re playing Pacman, racing along and eating dots, while escaping ghosts. Well that’s kind of what an enzyme does: except the dots need to slot into its mouth exactly (that is, be triangle-shaped) and the ghosts are high temperatures that will kill it.
Biological washing powders contain enzymes, which are proteins that speed up reactions in living organisms, often to break things into smaller pieces, and sometimes to join things together. They are the vital ingredient in the digestion of food, found in our mouths, stomachs and intestines. And they are peculiar about what they will work on: proteases break down proteins, amylases shred starch, lipases dissolve oils and fats, and cellulases digest plants. We don’t have cellulase in our guts, and so plants like lettuce and brussel sprouts pass through us untouched (but are important for smooth functioning of our digestive systems, and are known to us as dietary fibre). But some animals have bacteria or fungi that set up camp in their stomachs and produce cellulases for them – this explains how cows, sheep, camels and other ruminants can chew the cud and how termites can eat through wood.
But I digress (got to love biology). These crucial catalysts have been used for over 40 years in biological washing powders to break down food stains, just like our stomachs do, as well as blood, mud and grass marks. The brilliant thing is that, like Pacman, the enzymes carry on munching, finishing one reaction and then moving on to the next – they’re almost inexhaustible. The tiny particles that result from these chemical reactions are then washed away. Conventional soapy detergents break down stains too, but they are not very specific, and much higher concentrations are needed to achieve the same cleaning power.
Washing powder manufacturers use enzymes from bacteria in their biological products: for industrial production of these enzymes, gigantic vats of bacteria are grown, like huge pots of pale pink soup that are at the right temperature, acidity (pH) and are full of nutrients. The enzymes are harvested from these useful germs, purified and mixed into our washing powder.
Enzymes function in a very specific range of temperatures (broadly speaking, at human body temperature: 37°C), and so high temperatures (over 60°C) will kill them (see footnote 1). That’s why biological powders usually work at around 40°C, although the green box on top of my washing machine contains enzymes that have been engineered to work at 30°C – because cooler wash cycles are better for the environment and save us money.
I’m sure you will have gleaned that biological washing powders are great in so many ways: lower concentrations of them are needed for effective cleaning, they target exactly the stains we need them to, they are natural (and therefore biodegradable) and need much lower temperatures than regular soaps (sometimes up to 90°C). But concerns have been raised about their skin-friendliness – people have reported rashes and itchiness, particularly in babies and eczema-sufferers. A few scientists dismissed these claims, stating that the link to skin irritation was a “myth.” These ‘experts,’ however, were found to receive pensions and consultancy fees from Unilever, the giant home product corporation, which makes, surprise, biological powders.
My Non-Bio powder says ‘dermatologically tested’ and ‘kind & caring,’ while my Bio powder says ‘outstanding performance.’ The jury is out – it’s up to you to decide what feels better (but now you know how they work!).