We discuss and comment on the role agriculture will play in the containment of the CO2 problem and address protocols for terraforming the planet Earth.
A model farm template is imagined as the central methodology. A broad range of timely science news and other topics of interest are commented on.
Tuesday, August 30, 2011
Lager's Patagonian Roots
a neat discovery and important in reminding us that many potential hybrids
likely exist that we have not tried out yet.What is clear is that lager beer is a completely new creation from two
unlikely feedstocks that somehow married up.It is an accidental human invention.
reminds us also that the microbial universe is still loaded with local types
whose capacity for travel is real and rather disconcerting.A surprise melding is both possible and
likely and even highly common I our modern world. Boots on the ground
transports microbes globally today.
course the interesting ones are specialists and naturally geographically
limited without some effort.
500 Years Ago, Yeast’s Epic Journey Gave Rise to Lager Beer
Newswise — MADISON — In the 15th century, when Europeans first began
moving people and goods across the Atlantic, a microscopic stowaway somehow
made its way to the caves and monasteries of Bavaria.
The stowaway, a yeast that may have been transported from a distant
shore on a piece of wood or in the stomach of a fruit fly, was destined for
great things. In the dank caves and monastery cellars where 15th century
brewmeisters stored their product, the newly arrived yeast fused with a distant
relative, the domesticated yeast used for millennia to make leavened bread and
ferment wine and ale. The resulting hybrid — representing a marriage of
species as evolutionarily separated as humans and chickens — would give us
lager, the clear, cold-fermented beer first brewed by 15th century Bavarians
and that today is among the most popular — if not the most popular — alcoholic
beverage in the world.
And while scientists and brewers have long known that the yeast that
gives beer the capacity to ferment at cold temperatures was a hybrid, only one
player was known: Saccharomyces cerevisiae, the yeast used to make leavened
bread and ferment wine and ale. Its partner, which conferred on beer the
ability to ferment in the cold, remained a puzzle, as scientists were unable to
find it among the 1,000 or so species of yeast known to science.
Now, an international team of researchers believes it has identified
the wild yeast that, in the age of sail, apparently traveled more than 7,000
miles to those Bavarian caves to make a fortuitous microbial match that today
underpins the $250 billion a year lager beer industry.
Writing this week (Aug. 22) in the Proceedings of the National
Academy of Sciences, researchers from Portugal, Argentina and the United States
describe the discovery of a wild yeast in the beech forests of Patagonia,
the alpine region at the tip of South America, that apparently solves the
age-old mystery of the origin of the yeast that made cold-temperature
fermentation and lager beer possible.
“People have been hunting for this thing for decades,” explains Chris
Todd Hittinger, a University
genetics professor and a co-author of the new study. “And now we’ve found it.
It is clearly the missing species. The only thing we can’t say is if it also
exists elsewhere (in the wild) and hasn’t been found.”
The newfound yeast, dubbed Saccharomyces eubayanus, was discovered
as part of an exhaustive global search, led by the NewUniversity of Lisbon’s José Paulo Sampaio and Paula
Gonçalves. Aimed squarely at resolving the lager yeast mystery, the Portuguese
team sorted through European yeast collections, combed the scientific
literature and gathered new yeasts from European environments. Their efforts
yielded no candidate species of European origin.
Expanding the search to other parts of the world, however, finally paid
dividends when collaborator Diego Libkind of the Institute for Biodiversity and
Environment Research (CONICET) in Bariloche, Argentina, found in galls that
infect beech trees a candidate species whose genetic material seemed to be a
close match to the missing half of the lager yeast.
“Beech galls are very rich in simple sugars. It’s a sugar rich habitat
that yeast seem to love,” notes Hittinger.
The yeast is so active in the galls, according to Libkind, that they
spontaneously ferment. “When overmature, they fall all together to the (forest)
floor where they often form a thick carpet that has an intense ethanol odor,
most probably due to the hard work of our new Saccharomyces eubayanus.”
The new yeast was hustled off to the University of Colorado
School of Medicine, where a team that included
Hittinger, Jim Dover and Mark Johnston sequenced its genome. “It proved to be
distinct from every known wild species of yeast, but was 99.5 percent
identical to the non-ale yeast portion of the lager genome,” says Hittinger,
now an assistant professor of genetics at UW-Madison.
team also identified genetic mutations in the lager yeast hybrid distinctive
from the genome of the wild lager yeast. Those changes — taking place in a
brewing environment where evolution can be amped up by the abundance of yeast —
accumulated since those first immigrant yeasts melded with their ale cousins
500 years ago and have refined the lager yeast’s ability to metabolize sugar
and malt and to produce sulfites, transforming an organism that evolved on
beech trees into a lean, mean beer-making machine.
“Our discovery suggests that hybridization instantaneously formed an
imperfect ‘proto-lager’ yeast that was more cold-tolerant than ale yeast and
ideal for the cool Bavarian lagering process,” Hittinger avers. “After adding
some new variation for brewers to exploit, its sugar metabolism probably became
more like ale yeast and better at producing beer.”