Thanks V_R!

Cheers
FB

(here is a related article on the technical aspects of genetically engineering a brewer's yeast (just the first page, it gets more technical after this) full citation: Appl Environ Microbiol. 1991 Oct;57(10):2796-2803.)

During beer fermentation, yeast produces a-acetolactate and ao-aceto-a-hydroxybutyrate, which are intermediates in the synthesis of valine and isoleucine, respectively (5). However, minor amounts of these compounds leak out of the cells into the fermenting wort. These are spontaneously decarboxylated to the respective diketones, diacetyl and 2,3-pentanedione, but only slowly under brewing conditions (23). The taste and smell of diacetyl is detected at a very low level, 0.02 to 0.10 mg/liter depending on the type of beer and the method of analysis, and most people find it very unpleasent. Thus, for production of high-quality beer, a separate maturation period (lagering) of 2 to 6 weeks for green beer is needed, during which time diacetyl is taken up by the yeast cells and enzymatically reduced to acetoin. This lagering period is costly for breweries.

The enzyme a-acetolactate decarboxylase (a-ALDC; EC 4.1.1.5) decarboxylates a-acetolactate directly to acetoin without formation of diacetyl (29). The gene coding for this enzyme (a-ald or budA) is not found in yeasts but has been isolated from several bacteria (2, 8, 28). The a-ald gene cloned into autonomously replicating plasmids has been transformed into brewer's yeast (27, 29) and shown strongly to reduce formation of diacetyl during fermentation without affecting the quality of the final beer (29). However, plasmid strains contain extra foreign DNA and are usually unstable in long-term usage (29, 30). The gene has also been integrated as multiple copies into a yeast rRNA gene (7) without affecting the fermentation performance of the yeast or the quality of the final product (31).

Integration of a gene into the yeast genome, resulting in stable strains which carry minimal amounts of foreign DNA, is preferred to plasmid-carrying strains. Different techniques are now available for the transfer and expression of foreign genes in industrial yeast strains (12, 20). However, little is known about the effect of integration on the process behavior of industrial polyploid yeast strains. Because integration usually disrupts the locus in the chromosome, genes have mainly been targeted to nonessential regions such as to the HO locus involved in mating (32) or to the rRNA locus (7), which is present in over 100 copies in the genome. Integration into other loci such as LEU2 (14, 21) and ILV2 (4) has also been carried out in polyploid yeast strains. In this paper, we describe the construction of four different types of (x-ALDC-active, bottom-fermenting rewer's yeast strains. The genes from the bacteria Klebsiella terrigena and Enterobacter aerogenes encoding o-ALDC were integrated into the PGKJ or ADHI locus of the yeast genome by cotransformation and gene replacement. In addition, we compare the brewing properties of seven a-ALDC-active integrant yeast strains in 50-liter, pilot-scale brewing trials as well as the qualities of beers produced with these strains.

Just finished a major reorganization of my website, so please take a look and tell me what you think -- any problems, etc. www.2plus2is4.com

Cheers.

Bill Velek

Here's one reason:

Financial Times June 5, 1998
BONN, Germany
German brewers like to boast that the country's 482-year-old beer purity rules -- which say that only hops, malt, water and yeast can be used in beer production -- are as relevant as ever. But can a law drawn up by Bavaria's Duke Wilhelm IV in 1516 cope with 20th-century gene technology?

Opposition Social Democrats are demanding a change in the law to prevent genetically modified ingredients finding their way into the country's favorite alcoholic beverage, while the newspaper Bild has launched a "hands off our beer" campaign.

"It is a very sensitive subject. The Germans love to drink a lot of beer. It's a controversial issue," says Rolf Kleine, Bild's chief reporter in Bonn.

The problem is that Duke Wilhelm didn't think to differentiate between natural yeast and the genetically modified variety when drawing up his rules.

At the moment, it seems a storm in a beer glass. Genetically altered "turbo" yeasts, which offer the possibility of faster production, are still at the experimental stage. However, German politicians and the industry are taking the issue seriously.

Dieter Thomae, chairman of the Bundestag's health committee and a supporter of Chancellor Helmut Kohl's ruling coalition, will call for expert testimony on the subject when parliament returns from its recess in two weeks. A debate in the committee last week ended without a clear result. "I want to wait to hear the specialists," said Thomae.

The German brewers' association insisted last week that the industry did not use such products and that there was no need to do so.

But German brewers are under pressure. Consumption is falling -- the average German drank 34 gallons of beer last year, according to Ifo, the Munich-based economic institute, compared with 35.3 gallons in 1995.

More alarming, younger Germans see in their beer glasses "no exciting consumption experience," according to Ifo.

And with medium-sized breweries in particular at a cost disadvantage, the temptation to increase profits through faster production might prove addictive.

Erich Dederichs, spokesman for the brewers' association, said brewers using genetically modified ingredients would face stiff consumer resistance, making a ban superfluous.

The government argues that a strict ban on such ingredients would be unworkable because the raw materials are bought in the world market and will go through several stages of processing.

By RALPH ATKINS, The Financial Times

** NOTICE: In accordance with Title 17 U.S.C. Section 107, this material is distributed without profit for research and educational purposes. **

www.gene.ch

Good beer info you are presenting there, Fred. I also believe in leading by example, but in this instance there are not enough of us to present an example to the masses fast enough, so I think the school approach is at least worth a try. Not getting much feedback on 2plus2is4. Maybe if I can personally manage some success here in Arkansas, then there will be more interest. By the way, Fred, do you think you could provide a link to www.2plus2is4.com on our official team website when you get a chance. Still working on my site to smooth out some wrinkles. Takes a lot of time.

As for our team stats, we did a bit better today, which pushed us into #112, and we should pass Spain to move to #111 in two days.

Thanks.

Bill Velek