Dr Warhol’s Periodic Table of Microbes, The Small Guide to Small Things
89. Ac. Acetobacter
Love ‘em or hate ‘em, the Acetobacter make the world a more sour place to be.
There are around 4 dozen species of Acetobacter, all share the ability to produce acetic acid from ethanol in the presence of oxygen, and they live all over the world, wherever sweet fermentable things are found. This is great if you want to make vinegar and certain other industrial products. This is bad if you’re trying to make wine. It’s really bad. In fact, one of Louis Pasteur’s claims to fame is that he discovered that Acetobacter was responsible for wine spoilage way back in 1864, thus saving the French wine industry.
Because it specializes in converting ethanol to acetic acid, you can probably guess that Acetobacter is relatively ethanol-tolerant, and thrives in alcoholic environments that hinder many other microbes (it lives in beer and wine, some would call that lucky!). Because it makes acid, it’s not surprising that Acetobacter is relatively acid-tolerant.
Unlike yeast, which ferments in the absence of oxygen, Acetobacter is an obligate aerobe, which is why brewers and vintners are very careful about fermentation locks that exclude oxygen from the fruits and grains.
The best-known species is probably Acetobacter aceti (Dr Pasteur’s microbe), which is used to intentionally make acetic acid from alcohol in industrial quantities, mostly for use in vinegar. Sadly, it’s cheaper to make acetic acid from petrochemicals, but food-grade vinegar mostly comes from fermentation, to the tune of around 500,000 tons per year!
Another noteworthy species is Acetobacter xylinus, which synthesizes cellulose! Imagine that, a microbe that makes the same material as plant cell walls! Each microbe sort of spins a cocoon of cellulose around itself!
Acetobacter cells are Gram negative rods that measure about 0.5 to 0.7 microns wide by 1.8 to 2.0 microns long.
Copyright 2017 Warhol.
