Mussels on rock producing a clean water supply is an essential role of chemical
engineers, however many aquatic species are also able to clean water. The mussel is
an excellent example of a species that is able to do this. Mussels feed by extracting
food from water, filter feeding such as algae and bacteria. An adult mussel can filter
as much as 40 Litre of water in one day, and have been used to clean water in
polluted lakes and reservoirs.
Spider silk is more durable and elastic than the strongest man-made fibre. Spiders
produce their silk by spinning a protein fibre, or gossamer, in their spinneret glands.
Before spinning the silk consists of liquid proteins. However, as the liquid enters the
duct cells draw water away from the silk proteins and hydrogen is pumped in,
creating an acid bath. The un-spun silk transforms from a gel into a final solid fibre
as it is pulled through the spider’s spinnerets. These spinnerets excrete different
types of silk, from sticky to non-sticky to extra fine, depending on what the spider
Canaries could be considered to be the original process safety engineers. For years
they were used to sense carbon monoxide levels in mines, and are thought to be
particularly sensitive to methane as well as carbon monoxide and carbon dioxide.
The canary was a particularly useful safety expert because they are a highly vocal
species, their song can be used as a warning system. The birds are able to detect
toxic gases at an early stage thus giving the miners enough time to vacate the area.
It’s not only humans that process food. Honeybees make honey from the nectar they
collect from flowers, which is a sugar-water mixture. Invertase, an enzyme that
honeybees produce, converts most of the sucrose into glucose and fructose. A small
amount of the glucose is then converted into gluconic acid and hydrogen peroxide
by glucose oxidase. The gluconic acid reduces the pH of the honey to preserve it
and the hydrogen peroxide gives protection against microbes.
Eel Chemical engineers can produce energy, but some animals can produce
electricity from their bodies too. The electric eel is able to produce a huge electrical
charge which it uses to stun prey and protect itself from predators. Their bodies
contain electric organs with about 6,000 specialised electrolyte cells that can store
power like tiny batteries. When threatened or attacking prey, these cells will
discharge simultaneously, emitting a burst of at least 600 volts.
A number of species of ants are agricultural engineers. Some ants farm fungus and
others herd aphids in a similar way to how we farm cattle and take their milk.
Aphids excrete a sugary fluid that ants eat. Ants in fact ‘train’ their aphids to
produce their sugary excretions when stroked effectively milking them. The ants
care for the aphids, taking them to new pasture lands and protecting them from
According to the UNFAO cattle farming is responsible for 18 per cent of
greenhouse gases. Cattle emit a large volume of methane through burping and
flatulence, they are very dangerous environmental engineers. Of course, their
increasing numbers are due to our reliance on meat and dairy products for food, but
their impact is huge with emission from cattle now thought to be greater than those
Fiddler crabs work as ecosystem engineers through the burrows they dig. In salt
marshes their burrows are vital for the mangroves. At low tide, they channel an air
supply through the mud and direct it to the tree roots. The burrows also decrease
sulphate reduction and increase the concentrations of iron, enriching the ecosystem.
Silkworms are materials engineers and use their salivary glands to produce fibroin.
From this they create their cocoons by rotating repeatedly for up to 72 hours. Each
cocoon produces approximately one kilometre of silk fibre. During this time, the
silkworm eats 50,000 times its weight in plant materials.
Termites create mounds that work like factories. I think this gives the humble termite a
grade A in plant design. The termites use these constructions as huge process plants in
which they cultivate fungi. To ensure their survival, termites construct their mounds to
maintain a constant internal temperature, as a buffer from the natural environment.
I’ll confess to stretching my definition a little,
but chemical engineers are a versatile bunch.
The list demonstrates that some animals can
teach us quite a bit about chemical engineering.
And although I have only considered animals in
this post, its worth noting that we can find
plants, fungi, protozoa, archaea and bacteria that
are canny engineers too.