Selectively growing lactobacillus from sour dregs

[ChrisKennedy]

* purge the starter flask with CO2 and keep under an airlock
* no stir plate
* try to keep the temps elevated (around 100F)
* starter wort will be just water and lactose, no malt (or nutrient?)

The first 3 ideas are great; the fourth one is probably NOT a good idea. -Lactobacillus can only consume glucose/dextrose, the lactose won't really do anything for you, so I'm a bit confused about that one. (Yes kinda strange that an organism called "lactobacillus" can't consume a sugar called "lactose", BUT I didn't name either one.)

Lactobacillus definitely needs nutrients and malt itself can help with this. (See my previous post for major nutritional requirements.)
I'd say make a 45% malt, 50% dextrose/glucose/corn sugar (samething), 5% (pasteurized) honey starter and add yeast nutrients; and add just a large pinch of non-self-rising flour to a 1-2 liter starter.

Note/Disclaimer: Most of my lacto knowledge is limited to the most common lacto strain used in brewing, lacto delbruckii; other strains may have different characteristics.
Adam

Do you have a source for that other than the one sentence in Wild Brews?

[biertourist]

* purge the starter flask with CO2 and keep under an airlock
* no stir plate
* try to keep the temps elevated (around 100F)
* starter wort will be just water and lactose, no malt (or nutrient?)

The first 3 ideas are great; the fourth one is probably NOT a good idea. -Lactobacillus can only consume glucose/dextrose, the lactose won't really do anything for you, so I'm a bit confused about that one. (Yes kinda strange that an organism called "lactobacillus" can't consume a sugar called "lactose", BUT I didn't name either one.)

Lactobacillus definitely needs nutrients and malt itself can help with this. (See my previous post for major nutritional requirements.)
I'd say make a 45% malt, 50% dextrose/glucose/corn sugar (samething), 5% (pasteurized) honey starter and add yeast nutrients; and add just a large pinch of non-self-rising flour to a 1-2 liter starter.

Note/Disclaimer: Most of my lacto knowledge is limited to the most common lacto strain used in brewing, lacto delbruckii; other strains may have different characteristics.
Adam

Do you have a source for that other than the one sentence in Wild Brews?

What part? (Not trying to a be a pain-in-the-ass, I'm just not as organized as I'd like to be and I end up pasting items of interest into a running MS Office OneNote notebook that I have and I forget to add sources 2/3rds of the time so it'll take a little bit to track things back to sources so I'd like to know if there's a particular item you're looking for a source on.)

-The honey bit or lacto's nutrient requirements?

Here's one of two or three articles that I had seen; this one is from the Journal of Food Science, 2001; this is just the abstract as you need a Wiley Membership for the full thing. http://onlinelibrary.wiley.com/doi/10.1 ... x/abstract

Here's the Abstract Text:
In the first bolded/underlined sentence they refute the idea that honey (at least in a 5% concentration) inhibits bacterial growth, in the second they report increased lactic acid production. (I had another article from a South American university that came to a similar conclusion about 3 or 4 years later that I'll eventually locate...)

ABSTRACT: Twelve percent nonfat dry milk containing 5% (w/w) honey, fructose, or sucrose were pasteurized and inoculated with Streptococcus thermophilus, Lactobacillus acidophilus, Lactobacillus delbrukeii subsp bulgaricus, or Bifidobacterium bifidum. Inoculated tubes were incubated at 37 °C, 24 h. Samples were collected at 0 and 24 h and examined for (a) viability of bacteria, and (b) levels of fermentation end products (lactic and acetic acids) as measured by HPLC. Honey supported growth of all 4 organisms similar to other sweeteners and was not inhibitory. Lactic acid production was similar for all, except for bifidobacteria and was not influenced by sweetener type. Although lactic acid production was enhanced (p < 0.05) when bifidobacteria were grown in the presence of honey, acetic acid production was not affected. Various oligosaccharides found in honey may be responsible for enhanced lactic acid production by bifidobacteria.

Found the other one from Brazil that I was thinking of; it doesn't talk about increased acid production at all, though; only increased viability over a 46 day period of time and this test is with 3% honey vs. 5% in the other test.
http://www.scielo.br/scielo.php?pid=S01 ... ci_arttext


Adam

[EvilFrog]

* purge the starter flask with CO2 and keep under an airlock
* no stir plate
* try to keep the temps elevated (around 100F)
* starter wort will be just water and lactose, no malt (or nutrient?)

The first 3 ideas are great; the fourth one is probably NOT a good idea. -Lactobacillus can only consume glucose/dextrose, the lactose won't really do anything for you, so I'm a bit confused about that one. (Yes kinda strange that an organism called "lactobacillus" can't consume a sugar called "lactose", BUT I didn't name either one.)

I realize that there are many species and strains of lactobacillus out there and I can't be certain that each is able to metabolize lactose but I am guessing that you are not making the assertion that none can consume lactose. Lactose is a disaccharide of galactose and glucose. I guess it is true that they don't directly consume the lactose in the same way that yeast don't directly consume maltose. Yeast must first break it down into the two constituent glucose molecules before they can eat it. Lactobacillus (or at least the varieties I was aware of) produce the enzyme lactase , who's purpose in life is to break down lactose. I would think at that point it would have ready access to the glucose and I am not sure what (if anything) it does with the galactose.

If Lactobacillus were incapable of metabolizing lactose then we would not have yogurt right?

[biertourist]

* purge the starter flask with CO2 and keep under an airlock
* no stir plate
* try to keep the temps elevated (around 100F)
* starter wort will be just water and lactose, no malt (or nutrient?)

The first 3 ideas are great; the fourth one is probably NOT a good idea. -Lactobacillus can only consume glucose/dextrose, the lactose won't really do anything for you, so I'm a bit confused about that one. (Yes kinda strange that an organism called "lactobacillus" can't consume a sugar called "lactose", BUT I didn't name either one.)

I realize that there are many species and strains of lactobacillus out there and I can't be certain that each is able to metabolize lactose but I am guessing that you are not making the assertion that none can consume lactose. Lactose is a disaccharide of galactose and glucose. I guess it is true that they don't directly consume the lactose in the same way that yeast don't directly consume maltose. Yeast must first break it down into the two constituent glucose molecules before they can eat it. Lactobacillus (or at least the varieties I was aware of) produce the enzyme lactase , who's purpose in life is to break down lactose. I would think at that point it would have ready access to the glucose and I am not sure what (if anything) it does with the galactose.

If Lactobacillus were incapable of metabolizing lactose then we would not have yogurt right?

I definitely believe you; I thought it was rather strange at the time that I read it for just that reason. I remember reading something that specifically said that lactobacillus (Delbruckii anyway) could only consume dextrose/glucose and only produced lactic acid as a product of this process; now it sounds like I have to scratch that and start all over...

Definitely need to find where the heck I got this from; now I'm questioning everything in that section of my notebook...
(I'm almost certain I started this notebook section in WildBrews and then added to it from there... pulling it out again.)


Update: Now I think I know EXACTLY what Chris was talking about; and YES, it was from one page of Wild Brews: "Homofermentative, L delbrueckii produces one product (lactic acid) from one substrate (glucose)."
(I guess that explains why I don't see Delbruckii mentioned in the list of Lactic Acid Bacteria included in yoghurt cultures...)

-So is Delbruckii just the "odd man out" as the only lactobacillus strain that CAN'T ferment lactose or is this a common thing? (I see "Bulgaricus, Thermophilus, Acidophilus, and Plantarum" included in yoghurt cultures; does that make it a safe bet that these strains can consume lactose?)


Adam

[ChrisKennedy]

What part?

Sorry about that. The part where you said that lactobacillus d can't ferment anything besides glucose. I know that Sparrow says that in Wild Brews in a sort of throw away, matter of fact way, but he says it without reference and without any sort of explanation.

I am not positive either way, but I don't trust Sparrow in this instance as the sole source of this information.

[EvilFrog]

I definitely believe you; I thought it was rather strange at the time that I read it for just that reason. I remember reading something that specifically said that lactobacillus (Delbruckii anyway) could only consume dextrose/glucose and only produced lactic acid as a product of this process; now it sounds like I have to scratch that and start all over...

No worries.

I have pretty much decided from everyones feedback that I am better off with just purchasing a pack of an already isolated strain. At this point I am just interested in the approach I originally posted as an academic curiosity.

After considering the lactose thing a little more, I am not so sure it would even provide the selective pressure I was hoping for. Even if lacto uses it's secret weapon (lactase) to break the glucose free of the lactose, there is no guarantee that only the lacto will eat that glucose. Brett and saccharomyces would have just as good a shot at the liberated food as the lacto does if those enzymes were just freely floating around. There is plenty here I haven't the first clue about. Is the enzyme released outside of the cell or is it only used to unlock and pass the glucose through the cell wall? There would only be a selective advantage if it were the latter I guess.

Anyone know?