Magical Miracle Elixir: “better than bleach”. Secret ingredient? Bleach.

The Los Angeles Times published a bewilderingly hyped article today about an electrolytic device that makes “miracle” liquid. The article describes what actually is a kind of nifty gadget that uses an electrical current and a couple of semi-permeable membranes to generate (separately but simultaneously) a “degreaser” and a “sanitizer” out of ordinary salt and tapwater. They say that not only can you use one output to clean your dishes, the other one is “10 times more effective than bleach in killing bacteria”(insert a long string of exclamation points there). I just have one thing to say about that:


Continue reading Magical Miracle Elixir: “better than bleach”. Secret ingredient? Bleach.

I have a shocking confession to make.

I think I may be a nerd.

No, no, don’t try to deny it. I think it pretty much has to be true for someone who reads a 10-page scientific paper (hover or click here to see the reference) in order to learn that bacteria-snot is slimy. Yes, I am a nerd. And for that I am deeply, deeply….

Oh, who am I kidding? I like being a nerd.

Stainless Steel fermenters at a breweryFor one thing, being a nerd allows me to fully enjoy one of the perks that my job gives me – namely access to a lot of scientific papers that I otherwise wouldn’t be able to afford to obtain access to from the greedy [insert your favority profanity here] who insist on charging $30 for permission to look at a decades-old articles for a day. I should add that this perk includes Inter-Library Loan for articles that I can’t get online, and the service on campus is great so far. Same day delivery of a classic article from 1930 in what I’m guessing most people would probably consider an obscure journal.

It doesn’t have quite the same thing in it that I expected from the source that pointed me to it, but I think it can still be considered “classic”. I need to re-read it more carefully to make a final decision on this, but I think I have my next “The Giant’s Shoulders” article in time for this month’s upcoming issue. And, yes, the picture attached to this post is a hint (and, no, it’s not directly related to the bacteria-snot article mentioned above in any way…)

Since I’m sure you’re all aching to know:

According to the nutrition information on the back of the bag and some quick calculations, powdered Xanthan Gum has a density of a little over 610mg/ml (or about 10 slugs/hogshead).

I think I may be an Applied Microbiology nerd.

See, when I put dirty dishes in the sink to wash later, I often fill them up with water to soak. I didn’t see this much in Idaho, but down here in Texas I notice that if I leave them too long, the water will sometimes end up turning into a thick slime.

And here I am, wondering what kind of slime it is and if I could find a way to produce it in quantity and purify it (and then find something useful to do with it).

I’m also wondering if this delightfully simple gel electrophoresis technique might be scaled up for more production-type purposes.

Nerd Reading Spasm!

Did I mention the place I work has some amazingly spiffy perks for a nerd like me?

Last night, I was poking around pubmed looking for references to yeast and erythritol (namely, do yeast interact with it, and will they metabolize it?) I found precisely one relevant reference. From 1975. In a Czechoslavokian microbiology journal. A no-longer-existent Czechoslovakian microbiology journal. Even though it was a journal published in English, I didn’t figure I’d be able to find the article I was looking for. It did turn out that the greedy (insert long string of profanity here) anti-open-access “SpringerLink®” Netherlands organization has an electronic copy of the article…which I can get limited access to for a short time for a mere $34.00. Not going to happen, obviously.

Just in case the college had a subscription that would let me get to the article at no extra cost, I checked. No such luck. But…

…The campus medical science library just two buildings over from where I work has dead-tree editions of essentially the entire journal! Im name des Nudelmonster! Instead of paying $34.00, I got a photocopy of the article for about $0.50. Bonus: As I had hoped, the article[1] reports that erythritol is not metabolized by yeasts, although it is taken up to a small extent. That means I can add erythritol (or xylitol or sorbitol or whatever) to must or wort, and it’ll still be there when the yeast finish, leaving the resulting beverage still sweet. Hooray!

Plus, I was also able to get access to an electronic copy of a review of the uses of poly-?-glutamate[2], which I was bemoaning not having access to over on an interesting Small Things Considered post recently.

Speaking of reading, one thing I really could use are any worthwhile books on the general subject of applied/industrial microbiology, bioprocess engineering, fermentation, and so on. “Worthwhile” here means practical texts that are A)primarily about microbiological processes (as opposed to, say, bioengineering of plants) B)Reasonably technical, and C)Either “not very old” or “very old indeed” (I collect old science books).

I’m not a fan of’s abuses of the patent system, but I’m in a hurry since it’s past my bedtime already. Therefore, purely as a sampling of the kinds of books that sounded interesting to me, here is a selection in more or less random order of books that came up in a quick search on Anybody out there have any other suggestions?

Continue reading Nerd Reading Spasm!

Stir-Fried Random Ep 03: All I Want for Christmas Is…

A thanksgiving themed 'buy stuff' advertisementThanksgiving = Shopping, evidently. Anyway, since this is about the time of year when the vast population of my devoted fans around the world begin demanding to shower me with gifts and asking what kinds of gifts they should give me…this episode of Stir-Fried Random has some suggestions. Enough suggestions, in fact, that I didn’t even have room to include a Nerd Word, Emprical Observation of the Week, or Microbiology Microlecture. Therefore, while this episode will probably be slightly less interesting to the microbiology and computer-nerd focussed listeners, it should be of special interest to members of my immediate family, secret admirers, cultists who worship me as a living embodiment of divine spiffitude, and agents of the NSA, FBI, CIA, USDA, and Federal Department of Blog Enforcement who are busily profiling me. There is some other stuff though – please give it a listen, pass copies along to your friends, play it over the Public Announcement system at school, turn it into a techno-dance remix video on YouTube®, whatever.

As usual, direct download links for mp3 and ogg versions, plus <audio> tag support for those with really new browsers to listen in place, and embedded Flash-based mp3 player for everyone else who wants to listen in the browser instead of downloading and singing along during your commute or whatever.
(UPDATE 20081126: I’ve REMOVED the embedded player for now – it seems it ignores me when I tell it to wait until it’s told to before it starts playing. Autoplay annoys the heck out of me, and this seems to insist on it. The embedded player will remain gone until I get it to behave properly. Meanwhile, you can double-click or “right-click -> save as:” on the ogg or mp3 download link to get the audio files to listen to. Apologies to anyone ambushed by the unwanted auto-playing of the sound…)

Show Notes:
Continue reading Stir-Fried Random Ep 03: All I Want for Christmas Is…

Meme me!

As I mentioned in yesterday’s procastination excuse/hypnotic-cute-fuzzy-critter post, I was, without warning or provocation, viciously tagged by The Apprentice Lab Rat with a nasty case of the “5 Things” meme. O Cruel Fate!

I still need more audio to assemble Stir-Fried Random Episode 3. Meanwhile, here’s me meme:

(Note: These answers should not be used for psychiatric evaluation purposes. Unless it amuses you.)

5 things I was doing 10 years ago
Continue reading Meme me!

Yeast needs to breathe

Extracorporeal Membrane Oxygenation deviceAs readers may have guessed from previous posts, my brewing interests are minimally conventional. Fortunately, the Basic Brewing Radio podcast seems to regularly expand well beyond the usual “fermented malt flavored with a tisane of hops” thing (I need to try to make my own “Ginger Beer Plant” from scratch one of these days…). A couple of weeks ago, they did an episode covering an experiment on aeration methods which was very interesting. It does my ego good to know that I correctly guessed how the results would turn out. You can get a copy of the nice write-up of the experiment itself here, but here’s the simple version:

Continue reading Yeast needs to breathe

Fermentation: not just for alcohol

What does gluconic acid taste like, anyway?

Well, that was an interesting reminder. I’m tracking “fermentation” on Twitter, and caught a random reference to an interesting fermented beverage being made in Germany. The “reminder” I drew from this serendipitous reference was that “fermentation” doesn’t necessarily mean alcoholic fermentation.

“Fermentation” seems to be slightly tricky to define accurately. Most definitions seem to directly mention alcohol production from sugar, but this is only an example and not a definition. I’ve also seen the term used to mean simply “to grow a culture of microorganisms” (because the tank they are grown in can be referred to as a “fermentor”.)

Properly speaking, fermentation is what you get when you have microbes growing under conditions where the elelectrons that get sucked away from “food” molecules like sugars ends up on another, simpler carbon compound rather than something like oxygen, and therefore fermentation is implicitly anaerobic although that’s not the same as saying that fermentation cannot happen in the presence of oxygen (e.g. the Crabtree Effect, and of course fermentation of ethanol to vinegar requires oxygen). The end product is generally assumed to be organic acids (like acetic acid [vinegar]) or alcohols, and carbon dioxide. So, making beer and wine is fermentation. Making vinegar is fermentation. Making yogurt (lactic acid) is fermentation. Citric acid can be made by fermentation of glucose by Aspergillus molds, as can malic (apple) acid (see US Pat#3063910). You can make tartaric (grape) acid from glucose by fermentation as well (see US Pat#2314831).

I am familiar with the flavors of all of those products. One I’ve never directly tasted is gluconic acid, which is the main product of the fermentation process used to make “BIONADE®” (it seems to be written in all-caps everywhere).

According to their English-language page discussing their process – linked from the image at right, click to view – they are starting with malt, just as one would for beer, but instead of Saccharomyces yeasts, they are fermenting this wort-like liquid with “acid bacteria”. I’m going to hazard a guess that the bacterium in question is a strain of Gluconobacter oxydans or one of its close relatives. This group of bacteria is in the Acetobacteraceae family of bacteria which is involved in turning your wine into vinegar. It would appear that under the right conditions, the enzyme Glucose Oxidase (EC produced by G.oxydans converts glucose to a compound which reacts with water to form gluconic acid. BIONADE® then adds flavor extracts and juices to the filtered fermentation product, carbonates it, and bottles it.

Not being familiar with the flavor of gluconic acid, I’m aching to get my hands on some of this stuff and try it.

For another example of a relatively non-alcoholic fermented beverage, see also Kombucha, which is essentially sweetened tea fermented by acetic-acid bacteria and non-Saccharomyces yeasts…which I also have yet to taste.

geostr:50.4600,10.2208:200804110105-06:geostr (at least if Google Maps interpretation of the address I could find at the moment is correct, and assuming the information I dug up and my interpretation of it is correct, this should be the approximate location of the brewery responsible for BIONADE® production.)

The care and feeding of Saccharomyces

Let me pause now for a moment to review what I’ve learned so far:

  • Yeast are filthy little jerks
  • No, seriously. I’ve previously reviewed their promiscuous sex lives,
    their sexually-transmitted diseases, and their toiletry habits. Somehow, though I still want to do more brewing, so let’s continue.

    Bag of 'Parodina Yeast Chow'.  I am not affiliated with Purina Mills corporation!  This image is PARODY!

  • Yeast need to be fed particular sugars
  • The three major elements needed by pretty much every living thing for “food” are Carbon, Nitrogen (as reduced “amino” nitrogen), and phosphorus (as oxidized phosphate) (Reduced sulfur is also needed in small amounts for proteins). Glucose (“dextrose” or “corn sugar”), fructose, or sucrose (“table sugar”, each molecule of which is made of a molecule of glucose attached to a molecule of fructose) are all used as carbon sources by Saccharomyces yeasts. Possibly also Galactose under certain conditions[1]. Saccharomyces yeasts don’t appear to be able to use lactose (“milk sugar”, each molecule of which is made of a molecule of glucose and a molecule of galactose), so some recipes include lactose in order to ensure there is some residual “sugar” in the mix at the end, for flavor and “body”.

  • Yeast need reduced nitrogen (amino nitrogen or ammonia…or urea)
  • Aside from sugars, this seems to be possibly the most important yeast nutrient. The most
    “natural” source of this nutrient would seem to be amino acids or very short peptides (2-5 amino acids long). Apparently urea (carbamide) also makes a good yeast nutrient, but:

  • You don’t want TOO much nitrogen available to the yeast, or there’ll be excess urea dumped back into the brew
  • This could combine with the ethanol to make “ethyl carbamate”, which is considered
    a probable carcinogen, at least if it’s present at a high enough level. Obviously if you use urea as a
    yeast nutrient, that’s only going to increase the possibility of a problem.

  • Saccharomyces yeasts are effectively incapable of using proteins for nutrition.
  • Proteins can be a source of amino nitrogen (and carbon and sulfur), but like all real microbes, yeast cells cannot just “eat” chunks of protein. They have to be broken down into very small chains of amino acids or even as individual amino acid molecules before the yeast can suck them up and use them. Saccharomyces yeasts do not appear to normally excrete protein-digesting enzymes, so by themselves they cannot make any use of protein for nutrition[3].

  • Yeast need oxygen
  • Oxygen is necessary for making certain components of the cell membrane, in addition to it’s more obvious role in respiration. Without a way to replace used up membrane components, the yeast stop reproducing and eventually fall apart and die. There seems to be some suggestion that to a certain extent one can substitute some raw membrane material for oxygen here (either as “yeast hulls” or possibly even certain of the natural waxes on some fruits).

  • If you give yeast oxygen, though, they consume the sugars entirely instead of making alcohol…
  • …or do they? Between the “Crabtree effect” (when there are high concentrations of glucose, alcohol production continues even in the presence of oxygen) and indications in scientific papers[2], it seems SMALL amounts of oxygen may not be a problem, and might very well be beneficial.

  • Yeast need vitamins and minerals
  • B1 (“Thiamine”) is commonly mentioned, though apparently the need for it varies from strain to strain. Also potentially important are Pantothenic Acid (B5), Niacin (Nicotinic Acid, Vitamin B3), Biotin, Inositol, as well as Potassium, Magnesium, and trace amounts of calcium and a few other minerals[4].

  • Unhealthy yeasts are more prone to make (EEK!) Off-Flavors and Off-Odors (EEK again!)
  • For one thing, it seems to be a general rule that you don’t want your brew sitting on the corpses of dead yeast (the “lees” of wine, or “trub” of beer), because that is a potential source of (insert dramatic music and crash of thunder here)Off-Flavors and Off-Odors. Yeast dying and falling apart is also a major source of urea being dumped into the brew, too. Some strains of yeast under certain conditions, such as insufficient pantothenic acid, may be prone to producing nasty-smelling sulfides as well.

So, in most cases what we want to do when brewing is keep our yeast as alive and happy as possible, and get them to hurry up and finish our primary fermentation before they start dying off. Coming up: My (as yet untested) plot for accomplishing this – without specialized scientific equipment or materials.

[1] Wilkinson JF: “The pathway of adaptive fermentation of galactose by yeast” Biochem J. 1949; 44(4): 460–467
[2] Nagodawithana TW, Castellano C, Steinkraus KH: “Effect of dissolved oxygen, temperature, initial cell count, and sugar concentration on the viability of Saccharomyces cerevisiae in rapid fermentations.” Appl Microbiol. 1974 Sep;28(3):383-91.
[3] Bilinski CA, Russell I, Stewart GG: “Applicability of Yeast Extracellular Proteinases in Brewing: Physiological and Biochemical Aspects.” Appl Environ Microbiol. 1987 Mar;53(3):495-499.
[4] Fugelsang KG, Edwards CG: “Wine Microbiology: Practical Applications and Procedures” 2007; Springer Science+Business Media LLC, New York; pg 17

What really counts as a “microbe”?

Just a brief pre-post before the main one I’ve got brewing now (which will be posted either later today or tomorrow).

A tapeworm: Since when does 30-36 feet long count as 'micro'???Microbiology is the dominating topic of this particular blog, but I don’t think I’ve ever addressed what I consider to really count as “micro”biology. This isn’t necessarily an obvious topic. My old “Microbiology” book from 8 years ago, plus the textbook from last year’s “Pathogenic Microbiology” class both contained large sections discussing organisms that are visible without a microscope. Heck, the “Pathogenic Microbiology” text even had a whole section on spider and insect bites. And, tapeworms? Since when is “over 30 feet long” considered “micro”? As I like to say: It’s time for Microbiology to grow up and move out of Medicine’s basement.

So: Here are the defining features of what I consider to be a “microbe”, at least for purposes of what I tend to discuss here on the blog:

  • Obvious: the organism cannot be effectively examined visually without a microscope and individual organisms can virtually never be observed by the “naked eye”.
  • In nature, a full normal population of a microbe can and will develop from a single live cell, and isolated individual cells are reasonably commonly observed.
  • Microbes do not “eat”.

It’s that last point that prompted me to write this post, mainly because it’s such an important part of why microbes work and how they affect their surroundings, especially when it comes to food microbes. What I mean by “do not eat” is that they are incapable of taking large (microbially speaking) chunks of material into themselves to use. Any cell nutrient for a microbe must be in the form of small molecules, like sugars, small peptides or individual amino acids, and so on that can be easily transported across the cell membranes and through the cell wall where applicable.

The importance of this is that for a microbe to grow on a complicated substance like meat or bread (for example), they have to excrete specialized enzymes that break down the substances out in the environment into simpler components like sugars or small peptides. If a microbe cannot secrete a protein-digesting “protease” enzyme, it can be surrounded by tasty, nutritious proteins and still starve to death. If a microbe can’t secrete an amylase (starch-digesting) enzyme, it doesn’t matter that starch is made of nice yummy glucose molecules because they’re all wadded up into long chains of starch that the microbe can’t get at.

And that, finally, is important because it brings up issues of growing multiple microbes together to accomplish something. Sake, for example, is made by fermenting rice, but rice is made primarily of starch. Saccharomyces yeasts don’t make amylases, so in order to make sake, you also have to add a kind of mold (Aspergillus oryzae, one of the types of white-mold-with-little-black-specks that you may see growing on the bread you’ve left sitting around for too long). A. oryzae is also a microbe and therefore can’t “eat”, but it does produce amylase. Since the amylase is breaking down the starches outside of the cells, this means the released glucose is also available for the yeast to use.

Admittedly, my definition above isn’t perfect. On the one hand, it leaves out protozoa (like amoebae and the well-known Paramecium, both of which actually do take in “chunks” of food, but both of which most people would normally consider to be “microbes”. It also leaves IN things like mushrooms, which are not usually thought of as being “microbes” by people who aren’t microbiologists. And, of course, it leaves me with no excuse not to go and learn something about eukaryotic (“plant”) algae (as opposed to bacteria-algae, a.k.a. cyanobacteria) and diatoms. Suggestions for updating my definition may be left in the comments…

Just something that came up while I was assembling what will be the next post. Stay tuned.