a couple lacto papers

nonce · Post by **nonce** » Wed Jan 30, 2008 9:02 pm

I found a couple interesting papers and thought I'd pass them along.

I was curious about the competition between the lactobacillus vs the saccharomyces and found this abstract on lacto/yeast combinations and final ethanol production.

The upshot here is that it might be a good idea to do a normal 'sweet' fermentation first, and then do the lacto ferment. That allows you to maximize the amount of ethanol produced. Or if you want a strong lacto profile at the expense of ethanol output, do the lacto first.

http://tinyurl.com/2kb6eu" onclick="window.open(this.href);return false;" rel="nofollow

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When up to 10(9) CFU of bacteria/ml was present in mash, approximately 3.8 to 7.6% reductions in ethanol concentration occurred depending on the strain. Production of lactic acid and a suspected competition with yeast cells for essential growth factors in the fermenting medium were the major reasons for reductions in yeast growth and final ethanol yield when lactic acid bacteria were present.
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looks like you can get the full paper here (this link is found at the bottom of the page if you follow the link above):

http://tinyurl.com/37tjdc" onclick="window.open(this.href);return false;" rel="nofollow

Here's a paper on lactobacillus variants identified at the Glenkinchie distillery.

http://tinyurl.com/38w4u6" onclick="window.open(this.href);return false;" rel="nofollow

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Evolution of the Lactic Acid Bacterial Community during Malt Whisky Fermentation: a Polyphasic Study

The development of the lactic acid bacterial community in a commercial malt whisky fermentation occurred in three broad phases.

Initially, bacteria were inhibited by strong yeast growth. Fluorescence microscopy and environmental scanning electron microscopy revealed, in this early stage, both cocci and rods that were at least partly derived from the wort and yeast but also stemmed from the distillery plant. Denaturing gradient gel electrophoresis (DGGE) of partial 16S rRNA genes and sequence analysis revealed cocci related to Streptococcus thermophilus or Saccharococcus thermophilus, Lactobacillus brevis, and Lactobacillus fermentum.

The middle phase began 35 to 40 h after yeast inoculation and was characterized by exponential growth of lactobacilli and residual yeast metabolism. Lactobacillus casei or Lactobacillus paracasei, L. fermentum, and Lactobacillus ferintoshensis were detected in samples of fermenting wort examined by DGGE during this stage. Bacterial growth was accompanied by the accumulation of acetic and lactic acids and the metabolism of residual maltooligosaccharides.

By 70 h, two new PCR bands were detected on DGGE gels, and the associated bacteria were largely responsible for the final phase of the fermentation. The bacteria were phylogenetically related to Lactobacillus acidophilus and Lactobacillus delbrueckii, and strains similar to the former had previously been recovered from malt whisky fermentations in Japan. These were probably obligately homofermentative bacteria, required malt wort for growth, and could not be cultured on normal laboratory media, such as MRS.

Their metabolism during the last 20 to 30 h of fermentation was associated with yeast death and autolysis and further accumulation of lactate but no additional acetate.
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pintoshine · Post by **pintoshine** » Wed Jan 30, 2008 9:10 pm

Real good articles. The 7.6% of my 10% isn't much is it?
that's like 7 parts per thousand. I lose more than that due to spillage.

nonce · Post by **nonce** » Wed Jan 30, 2008 9:19 pm

Maybe another question is whether the lacto's produce different metabolite profiles depending on whether they're running as the primary or secondary.

But I don't think my google skills are quite up to the task of tracking down something that obscure. So I guess I'll just have to try it both ways.

nonce · Post by **nonce** » Wed Jan 30, 2008 9:21 pm

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I lose more than that due to spillage.
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Yeah, that's what I tell *my* wife too.

nonce · Post by **nonce** » Wed Jan 30, 2008 9:41 pm

http://tinyurl.com/2lmvjc" onclick="window.open(this.href);return false;" rel="nofollow

Citric acid metabolism in hetero- and homofermentative lactic acid bacteria.
D F Drinan, S Robin, and T M Cogan
Small right arrow pointing to: This article has been cited by other articles in PMC.
Abstract
The effect of citrate on production of diacetyl and acetoin by four strains each of heterofermentative and homofermentative lactic acid bacteria capable of utilizing citrate was studied. Acetoin was quantitatively the more important compound. The heterofermentative bacteria produced no acetoin or diacetyl in the absence of citrate, and two strains produced traces of acetoin in its presence. Citrate stimulated the growth rate of the heterofermentative lactobacilli. Acidification of all heterofermentative cultures with citric acid resulted in acetoin production. Destruction of accumulated acetoin appeared to coincide with the disappearance of citrate. All homofermentative bacteria produced more acetoin and diacetyl in the presence of citrate than in its absence. Citrate utilization was begun immediately by the streptococci but was delayed until at least the middle of the exponential phase in the case of the lactobacilli.

alice · Post by **alice** » Thu Jan 31, 2008 12:59 am

Damn you guys are some good researchers.

I've got a batch of lacto-first UJSM and a batch of yeast-first UJSM fermenting side-by-side right now, can't wait to run 'em and see the difference.

Old_Blue · Post by **Old_Blue** » Thu Jan 31, 2008 3:50 pm

approximately 3.8 to 7.6% reductions in ethanol concentration occurred depending on the strain.

What would happen if you just up the % to begin with to balance it out? Might take a day longer to finish. Personally I'm more concerned with quality than losing an ounce or two. Just a question.

Excellent find on the article btw