Posts Tagged ‘sake’

The brewer’s yoke, the domestication of microbes

// July 15th, 2012 // Comments Off on The brewer’s yoke, the domestication of microbes // Recent Research

Something happened when I was spliced, something wrong. Some random event in my chromosomes, I suppose it was. In any event, I wound up lacking. My sister took all the toxin genes, and I was left with nothing.

It’s a scary world out there for a fungus without a toxin. How would I strike fear into the hearts of all animals who dared to eat the plants I was eating? How, without my precious aflatoxin to attack the liver, causing acute sickness or eventual cancer?

Quite simply, I’m surprised I lasted as long as I did before they found me.

Indeed, I’m not sure how they did find me. I had a pretty good disguise, growing colonies of blue along the endless islands of white rice grains, just like my toxic cousins always had. Safe from munching animals by my don’t-eat-me mimicry, the promise of sickness is the discoloured rice.

For some reason, these sake brewers saw past it all. I thought I was a goner when they lifted me up from the wild and plonked me into a house of wood.

Then I saw the food.

A. oryzae in heaven. Image by Forrest O.

It’s hard for mould like me to see, lacking in the eye department, but I knew it was there. An endless carpet of steamed rice. With my filamentous fronds I could touch it. Drill down into it and grow cottony soft, sprout fruiting bodies on the surface and spread on and on.

Call me legion, for we are many. Better yet, call me qū meí jūn in Pinwin, kōji-kin in Japanese, nulook-gyun in Korean or the grandiose Aspergillus oryzae in scientific circles. Back then, some 2000 years ago, I didn’t know who I was, or that I would one day be the National Fungus of Japan.

That’s when the changes happened.

I didn’t notice at first, I don’t know that there was ever a master plan. It felt… natural. Human hands, bristling with microbes and pitted with pores, dropped me into heaven. And when I had eaten the heaven for a time, they picked me up and dropped me once more into fresh heaven.

Incomprehensible! These hands must have spent hours polishing the rice to remove all the husks, then steamed it to perfection, cooled it so I didn’t burn my filaments, then spread it out – just for me! It was like being a king! King Kōji-kin!

I'm a national icon, and pretty cute too. Image by Ryoku Kasinn

As they fed me and I ate, we gradually adapted to please one another. Heaven grew ever more heavenly, until the temperature and humidity was just so.

For my part, I started growing much faster, hell, I had brilliant conditions for it and not a doubt in the world that I could grow as fast as I pleased. Fearlessly fast.

Over generations, they selected only the best for their purposes, which at that stage I knew nothing about. They selected the sons and daughters (hell, we’re all of one gender here) that could best turn rice starch to sugar. They also preferred fungi of least colour, but most smell and flavour. Each generation, the best of me would be plucked and propagated.

Turning starch to sugar is a tricky thing. I suppose the point of starch is to tie up the sugar molecules into a big, complex network so the plant can use them later. For me, kōji-kin I secrete the amylase enzymes, biological machine that chops starch into pieces of sweet. From a couple of recently-licked hands, I’ve learned humans make the same enzyme in their saliva. My amylases, however, not only make glucose, but a few other sugars that produce a wonderful flavour.

But why, pray tell? Have you worked it out yet?

Winemakers use yeast to turn the natural sugars in grapes into alcohol. Beer brewers must malt their barley, partially growing the seed to convert starch to sugar, to ferment it with yeast into alcohol.

And I, the humble fungus, plucked from the wild a millennia ago for a deficit in character. My non-toxic self excels, above all other moulds, in turning rice starch into sugars.

From the beds of heaven, me and my alchemical rice is transferred to the fermenting tank. Mixed with yeast, water and more rice, then left to stew in our own juices for a month.

This mash is pressed and filtered, and the sweet, alcoholic liquid that pours forth is bottled as sake.

Not to ring my own bell filaments, but I make soy sauce and miso too. That’s a whole meal – appetizer, main, and a drink.

Domesticated A oryzae (left) and wild A flavus (right). Image by John Gibbons, Vanderbilt University

These days I hardly recognise myself! So much of me has changed by growing with the sake brewers. Though I still share some 95% of my genome with my wild and toxic cousin A. flavus (and you, human reader, share 99% of yours with a chimpanzee), I am given all I could ever want to eat and praised world-over for my skill in sake making. While A. flavus, the wild thing, is targeted daily for a war against fungi with resistant crops and competitive yeasts.

What must the wolf think of the dog? Or the auroch of the cow? Well, to their accusations I say this: We may change our genes and appearance for protection and care, but, in doing so, we also mould the humans who cooperate with us. Through their attentions and skills, they, too, are domesticated.

This story was inspired by this recent research by Vanderbilt University into the domestication of microbes. “Although people don’t often think about it, we haven’t only domesticated animals and plants, but we have also domesticated dozens of different microbes.” – Assistant Professor of Biological Sciences Antonis Rokas in the press release. You can find more information on brewing sake here, and a beautiful description of koji pampering by interns at a sake house in Japan who blogged their experiences.

ResearchBlogging.orgGibbons, J. et. al. (2012). The Evolutionary Imprint of Domestication on Genome Variation and Function of the Filamentous Fungus Aspergillus oryzae Current Biology

Sometimes scientists just have to douse experiments in alcohol

// January 15th, 2011 // 1 Comment » // Recent Research

Superconductor supermarket

Superconductor supermarket. Image by andreasmarx

In which scientists get drunk and pour their beverages on compounds to create superconductors.

It’s no secret that I cook better with wine. I’m not just talking about a dash of red in pasta sauce or half a bottle of cheap white in risotto. I mean, when I’m tipsy I’m generous with the flavours and cook in a twirling, happy sashay of creation. But who knew it was the same with science?

Superconductors are metals at very low temperatures (6 Kelvin) which gain certain properties: Namely that the normal resistance drops to zero and they start conducting electricity incredibly well.

The experiment conducted at the National Institute for Materials Science in Japan involved soaking compounds (powders of iron, tellurium and tellurium sulfide) in different fluids, then cooling them and testing how well they conducted electricity.

First experiment: pure water. Results = boring. (10% superconducting volume fraction)
Second experiment: water plus ethanol. Results = yawn. (11%)
Third experiment: pure ethanol. Results = worse than water. (6%)

At this stage, I can only assume the scientists got drunk. They got a variety of different drinks (whiskey, sake, wine, etc) poured out 20 mL shots and soaked the compound in their boozy concoctions. When they tested conductivity, the results were surprising. Whiskey did well, beer did better, and red wine was streaks ahead with a whopping 63% of the material showing superconductive properties. For some reason commercial drinks created better superconductors than pure ethanol and water.

Here’s a graph of the results.

superconducting drinks

Graph by Keita Deguchi

As you can see, red wine is a clear winner, followed by white wine, beer, sake and other commercial drinks. At the bottom is boring old ethanol/water. Clearly what was lacking was a bit of FLAVOUR. That, or oxygen, particulates… actually they don’t know why it happened. More experiments need to be performed. Probably every Friday night from 3pm.

Still, it’s a fantastic case of serendipity. Plus, once the results were in, all the drinks were ALREADY THERE for celebrating! Sweet!

The paper is available free from arXiv – Deguchi K. et al “Superconductivity in FeTe1-xSx induced by alcohol”






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