Down and Dirty

Bacteria’s electric motors

It turns out, electric motors are even more common than we previously thought. They’re everywhere…even in bacteria.

As Dr. Karl Kruszelnicki explained in last week’s edition of his “Great Moments in Science” simulcast, bacteria don’t just spread the way they do without means of locomotion. In their case, that involves microscopic propellers and “self-assembling” electric motors.

First of all, let’s clear the air on bacteria’s dirty reputation. The immediate connotation (to those of us who aren’t scientists, or at least science majors) is that bacteria is bad. It’s the technical term for “germs”, it’s dirt, it’s grime, it’s disease, it can lead to health infections (alike, but not the same as, a virus). All true. Only thing is, bacteria has some hardworking cousins who do the dirty work for the greater good. For example, E. Coli are found in the intestines of humans and aid in digestion. Streptomyces is used in making antibiotics. Rhizobium are helpful bacteria found in the soil. And, as Dr. Kruszelnicki tells us, some of these also use our favorite mechanical equipment, albeit miniaturized, to swim.

First, some bacteria use propellers powered by tiny electric motors to swim in their environment. These electric motors are able to assemble themselves. Finally, Kruszelnicki writes, “these invisible electric motors are much more efficient than any motor we can currently build.” Bacteria’s “legs” are cilia and flagella, made mostly from proteins and used for propulsion. The “motor” is a compound of filaments embedded in the cell wall. These get their energy from charged ions crossing the cell membrane.

“Astonishingly, the energy efficiency is close to 100%, much higher than we can achieve with our human-made electrical motors,” Kruszelnicki says. 

Now, if only we can enlist bacteria to work at plants and facilities.



  1. Nobels & Whistles | Electrical Apparatus Magazine - October 13, 2016

    […] academy said the scientists’ work to develop this miniature technology could lead to a […]

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