Why do the stupid fungus use 'inefficient' fermentation in preference to efficient respiration ?

Let us be clear - virtually all common lifeforms can provide energy for themselves by both respiration and fermentation.

Respiration uses oxygen to efficiently extract all the energy from the chemical bonds found in sugar like substances.

Fermentation does not use oxygen and hence can only extract some of the energy from some of those chemical bonds.

Many bigger beings, like us humans, only use low efficiency fermentation when we can't get sufficient oxygen for high efficiency respiration - the classic case for humans is during long, hard, fast physical activity like running in the Boston Marathon.

But why then do a whole lot of 'primitive' microbes perversely continue to use low efficiency fermentation --- even when lots of oxygen is available ?


This is the so called Crabtree Effect - first widely noted by university scientists post 1929.

(And first noticed by brewing types back in 10,000 BC !)

The discovery of this fact by chemists during the Age of Progress was the key reason why my parents and I were duly taught in school that beings like the fungus were but primitive relics of simpler, stupider times --- living fossils.

Today the scientific consensus is that at the very beginnings of Life, simple respiration came first and complex fermentation came later !

Admittedly, this news hasn't reached most scientists not involved in this specialized area of research and the bulk of them still think of fermentation as simple and stupidly inefficient.

We humans greatly profit from this 'stupidity', of course.

Because instead of the sugars being reduced to low energy CO2 and water 'waste', it goes out as relatively high energy ethanol 'waste' --- beer, wine and spirits. And the secret that makes bread rise.

But of course chemists are not really evolution experts.

Because real evolution experts must explain why such stupid behavior has been so well rewarded by the natural selection gods.

After all, fungus having been on earth for hundreds of millions of highly successful years versus the human chemists' very brief sojourn on Earth.

We can start by noting fungus only move to fermentation mode when the amount of available sugar to eat is high, regardless of the amount of oxygen about.

Going at that mountain of sugar with oxygen yields the most energy per unit of sugar, but it takes a lot of time and needs a lot of cellular machinery and cellular surface space.

Fungus can't really increase their factory size* endlessly, unlike our human companies.

Instead they shift to using their existing limited cellular surface space and machinery so as to increase their energy-gaining throughput,in terms of units of time, even if it results in a low yield per unit of sugar.

So they certainly do waste the sugar, but after all there is lots and lots of it about ---- and in doing so, they gain more energy per minute for themselves than by the slow, bulky but efficient respiration route.

As the lucky individuals closest to the mountain of sugar, they bulk up quickly all set to reproduce lots of spore children when the time comes --- even if their reproductive success comes at the cost of denying useful sugar to their fungal distant cousins.

(During the process of bulking up, the fungus does use some of the readily available oxygen all right - but as a structural material rather than as part of an energy extracting process.)

As is usual, once scientists (and economists) move beyond a reductionist way of viewing reality - looking instead at the whole picture at the top level of an ecosystem, the benefit of behavior that seems stupid and 'inefficient' at the level of the reductionist chemists' atoms and molecules, becomes much clearer...

* It is known that microbes do change the shape of their cells to a limited extent, to alter their surface to volume ratio to economically maximize food intake in times of extreme starvation or extreme abundance : long and thin, small and round, large but flat & shallow , etc.

The poor poor pitiful slimed - always misunderstood , always maligned ...

In 1928, the year Fleming discovered and then rejected (three times) the penicillium that makes lifesaving penicillin, there were about two billion humans on the planet.

That year , tens and tens of millions of miscarriages and premature deaths were caused or hastened by bacteria and virus.

Everybody knew somebody who had died from bacteria or virus - everyone knew the primeval fear of raging epidemics.

That same year tens and tens of hundreds of people died from fungus - their individual deaths - spotted here and there almost at random- usually just seen as the result of eating 'bad' food.

Except in a few remote cultures, almost no one knew anyone who had died from fungus.

Yet in the world of cultural horrors and monsters , did we see this reality reflected at all ?

Of course not - no giant viruses or bacteria stalking the innocent maiden of movie screen and genre literature ---- it was always some faceless, shapeless, smelly, flowing, slimy gooey thing : fungus, in other words !

One suspects that this is because the virus or bacteria seems invisible ( though if we walk across the rocks of a shallow stream, the slime on the rocks is bacteria made visible).

But while most mold colonies are as equally invisible as bacteria colonies, the fungus frequently grows to highly visible sizes - easily drawfing even the bacteria colonies force feed to visible size on lab petri dishes.

In our homes or out in forests , molds easily grow big, fast, furry and slimy --- and always are extremely colorful.

The slime mold (a mold indeed as the word is understood by all but experts, just not a fungus mold) actually moves and quivers - a real life monster just waiting to be scaled up to the movie screen.

But molds are definitely the least harmful to humans of the big four of microbes life forms - more a danger to plant life than to humans and animals.

They simply are - to turn a phrase around - in sight and in mind ....

Dawson's penicillin 1940-1945 : made in the Public Domain , FOR the Public Domain

Howard Florey's penicillin 1940-1945, by way of pointed contrast, was Pure penicillin for Purely military use only.

He believed that penicillium were tiny ancient life  and so , by definition , linear progressive Evolution's "Yesterday's Men" .

He was sure civilized scientific Man was bound to make penicillin better and cheaper than some slimy mold in a sort of  witch's caldron .

But, in fact , chemists actually needed hundreds of millions of dollars - in 1940s dollars - together with tens of thousands of tons of structural and stainless steel  to make a whole series of chemical factories, just to get started on making penicillin.

All those big plants, together with lots of staff, a whole lot of energy and many corrosive solvents were Man's way of making penicillin.

They needed to be build expensively strong in order to safely apply high pressure and high & cold temperature over and over in many steps.

All this to replicate what a incredibly tiny fungus cell (sixty pico grams in mass) could produce at ordinary temperatures and ordinary pressures out of a little dirty water and a bit of decaying organic material.

That tiny fungus factory weighed about one billion trillion times less than all of the factories needed to make the basic chemicals that went into the final penicillin synthetic factory.

So if you thought that perhaps the tiny fungus could do the job better and cheaper, then you were with Dawson.

Now, just as how you viewed the possibility of the continuing viability of small beings coloured the type of penicillin factory you preferred, it seemed to also colour who you thought the penicillin should help.

So, Florey: big factory penicillin for big armies only ; Dawson : small factory penicillin for small people everywhere.....

A forgotten meme from "The Golden Age of Mysteries" held sway over wartime penicillin : to the detriment of the dying

The grey-haired teenagers of the 1870s to 1890s, the guys who actually ran World War Two, grew up on the stories of the Golden Age of Mysteries and Detectives, starting with Sherlock Holmes' Study in Scarlet in 1887.

And one thing you quickly learned in all those thousands of books in dozens of languages was that the formula that the spy had stolen from the safe - the formula upon which the fate of the Empire ( or perhaps even the world) hung - was never a formula in physics or biology or geology or astronomy.

It was always a formula in Chemistry : always a formula for the synthesis of some extremely powerful explosive or fuel or drug.

Chemistry and synthesis in those days held all the non-chemists in shock and awe --- from at least the1870s until after Hiroshima in 1945.

Much as physics held the minds of non-physicists between 1945 and 1985 and the way micro-biology still holds our non-biologist brain cells.

(Ever since the day we-the-laity first discovered that courts could convict serial murders just on the scientific basis of their trace DNA left at the scene of the crimes.)

The solution for almost every problem that wartime penicillin faced - and there were many - was "throw more chemists at the problem".

The solution for the shortage of penicillin being produced  just had to be "synthesis it - we humans have to be way smarter than mold slime could ever hope to be".

The real solution  - when it came - was surprisingly mundane : like farmers have done for thousands of years, we simply went out and looked for better breeders - in this case, better breeders who gave us, not more milk , but more penicillin instead.

The solution was not a chemical formula from the collective brains of thousands of top chemists, but rather the eyes of one, rather ordinary, mycologist in a fruit market in Illinois.

Remember the black humour vogue for "thin books" ?

(The best known was "Italian War Heroes" - unfair because even the Germans and British felt that the Italians were frequently brave and often very effective.)

the ultimate "THIN BOOK"

A better, truly thin, book would be "Mycologist War Heroes" .

Exactly where were those bastards between 1928 and 1945 anyway ?

They mightn't have been asked, very often, to paid work on penicillin - but they didn't seem to be exactly eager to volunteer either : and the importance of penicillin during WWII  (aside from its chemistry aspects from 1943 to 1945) was hardly top secret .

I suspect most mycologists spent the 'ultimate war between good and evil' either stamp collecting or devising secret ways to use funguses to destroy enemy food crops, aka germ or biological warfare.

Then civilians deaths could be got in truly wholesale amounts - not merely in the paltry retail numbers that Bomber Harris's aerial bombing had produced.

If wartime mycologists had gotten their wicked way, fungi would have still done their part to help win the war.

But not by saving millions, but rather by killing millions.......