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[SANET-MG] GM microbes sweet on dairy products
The article below is about GM microbes in dairy products. The patent
holder fro the GM microbe states "It is our opinion that GMO is much
safer than a randomly mutated strain. They are much more controlled,
with much more predictable side effects," That is easy enough for the
patent holder to say but I disagree!
GM bacteria could naturally sweeten dairy
By Stephen Daniells
10/4/2006- By adding a novel genetically engineered bacterial strain to
dairy, the fermentation process is limited to converting lactose to
glucose, a technique that could remove the need to add sweeteners to
The research, part of the EU-funded Nutra Cells project
(QLK1-CT-2000-01376), also has implications for lactose intolerance
because, by converting the lactose in the dairy to glucose, the final
lactose content of the dairy is significantly reduced.
"The resulting strain can be used for in situ production of glucose,
circumventing the need to add sweeteners as additional ingredients to
dairy products," wrote lead author Wietske Pool from the University of
Groningen. "Moreover, the enhanced removal of lactose achieved by this
strain could be very useful in the manufacture of products for lactose
The researchers, led by Professor Oscar Kuipers from the University of
Groningen, screened numerous strains and plasmids of directly engineered
Lactococcus lactis bacteria. The tests were performed on L. lactis
strain NZ9000, constructed from the L. lactis strains LL108, LL302 and
Lactococcus lactis is used extensively in the dairy industry in the
production of fermented milk products, and has a relatively simple
carbon metabolism pathway. By directly engineering this strain of
Lactococcus lactis the researchers were able to delete genes that coded
for glucose metabolism by the bacteria. This was achieved by disrupting
the main sugar transport system, the so-called sugar phosphotransferase
Lactose is a disaccharide, meaning it is made up of two basic sugar
molecules, a galactose molecule bonded to a glucose molecule. By
deleting certain genes in the lactose-PTS, it was possible to create a
bacterium (NZ9000Glc-Lac+) that selectively fermented the galactose part
of the lactose, but not the glucose part. The glucose then accumulated
outside of the cell, in the dairy product.
One of the genes deleted has only recently been discovered - glucose-PTS
EII-cel (ptcBAC) - while the others are known - glucokinase (glk) and
Professor Kuipers told FoodNavigator.com that the fundamental research
used a lab strain and that some extra work would be needed to take it to
an industrial setting, but one of the main challenges is not technical
but industrial and consumer attitudes and regulations regarding
genetically modified organisms (GMO), particularly in Europe.
It may be, said Professor Kuipers, that this kind of bacteria would pass
EU regulations, since it is based on gene knockout, and recombinant DNA,
and could be considered as self-cloning. No non-bacterial DNA is added.
And in the US, where industrial, regulatory, and consumer issues
regarding GMOs are different to Europe, the research "could be of interest."
"It is our opinion that GMO is much safer than a randomly mutated
strain. They are much more controlled, with much more predictable side
effects," he said.
The viability of the strain was tested both under synthetic laboratory
conditions, as well as in skim milk with a lactose content of about five
per cent. In both sets of tests, NZ9000Glc-Lac+ increased the glucose
content, and decreased the lactose content. The fermentation process was
stopped when the pH of the milk fell to 4.2, as occurs in milk
fermentation under natural conditions.
"L. lactis NZ9000Glc-Lac+ could be used to produce glucose from lactose,
which could serve as a natural sweetener in fermented dairy products.
This in situ produced glucose could replace, at least in part, the
frequent addition of other sweeteners to dairy products, as the
sweetness of glucose is about 60 per cent of that of sucrose," wrote the
researchers in the September issue of the journal Metabolic Engineering
The technique could also impact on the taste of the final dairy product,
they said, since glucose production in combination with less
acidification of the product would produce a milder taste.
And since the strain uses lactose to produce the glucose, there is more
effective removal of lactose from the dairy product.
"Therefore, the strain could be used as a nutraceutical to produce milk
fermentation products with lower residual lactose concentrations, which
would be suitable in a diet for individuals suffering from lactose
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