I thought this may be of interest to this thread, it doesn't...

I thought this may be of interest to this thread, it doesn't mention Ethtec but lots of info on the idustry.

26 May 2010 by Helen Knight

THE feast is coming to an end for biofuel producers. Their supposedly clean, green fuel has been gobbling up some of the choicest food crops, including corn, rape and soya, leading to controversy and protests around the world.

Now the industry increasingly finds itself forced to dine on more meagre fare: the inedible scraps left by other industries. But it is now finding ways to turn these scraps into a hearty dinner - and it could even provide for others, too.

First-generation biofuels are a victim of their own success. Talk of climate change and energy security led to a surge in crops grown to fill fuel tanks rather than stomachs, bringing food price hikes and changes in land use.

So the goal now is to efficiently convert so-called "second-generation" sources - grasses, wood, paper and the inedible waste from food crops - into biofuels. One of the main biofuels is bioethanol, which could supplement or even replace gasoline as a transportation fuel.

Squeezing meaningful quantities of bioethanol from this waste is challenging but not impossible. In a report last year, the Biotechnology Industry Organization, a lobby group based in Washington DC, estimated that second-generation biofuels could reduce annual US petroleum imports by nearly $70 billion by 2022. The US imported $24.7 billion in energy-related petroleum in January 2010 alone.
One report estimates that biofuel from plant waste could reduce US petroleum imports by $70 billion

Bruce Dale of the Office of Biobased Technologies at Michigan State University in East Lansing is even more optimistic. He thinks second-generation biomass could, in theory, generate 350 billion litres of biofuel per year - essentially equivalent to all of the US's oil imports.

In order to do so, ways must be found to break down the cellulose that forms the inedible cell walls of green plants into an easily digested form that can be converted into sugars using enzymes. Those sugars can then be fermented into bioethanol.

Dale and his colleagues have developed a technique called ammonia fibre expansion (AFEX) that he says can convert over 90 per cent of the cellulose into biofuel. AFEX involves adding biomass to an ammonia-filled chamber at 100 C and up to 20 times atmospheric pressure. After 5 minutes the pressure is explosively released, and the combined effects of the hot ammonia and rapid depressurisation breaks up the cell wall, pulling apart its cellulose microfibres. This makes it easier for enzymes to reach the cellulose molecules, meaning more of it can be turned into sugar.

Finally, these sugars are fermented with yeast or bacteria to produce bioethanol or other biofuels. The technique produces 300 litres of biofuel from a tonne of plant material, Dale says, compared with around 160 litres per tonne using existing commercial techniques.

The university has licensed the technology to a company called MBI in Lansing, Michigan, which plans to build a pilot plant that by the end of this year will be able to process a tonne of plant material per day. It hopes to have a commercial plant running by early 2012, processing 250 tonnes of biomass per day and generating around 27 million litres of biofuel each year, says David Jones of MBI.

It is not the only company with big claims for efficient bioethanol yields. ZeaChem, based in Lakewood, Colorado, says its process can convert a tonne of feedstock into over 500 litres of bioethanol. That's because the firm uses acetogenic bacteria found in the guts of insects - rather than standard yeast - to convert the sugar into ethanol.

Fermentation produces carbon dioxide, and so reduces the amount of carbon available to be converted to ethanol. The acetogenic bacteria directly convert all of the carbon in sugar into acetic acid, which is then combined with hydrogen to produce ethanol without the carbon losses, the firm claims.

Microbiogen, a firm based in Lane Cove, New South Wales, Australia, says fermentation can be profitable even with carbon losses. Its fermentation process yields a surprising by-product - plentiful supplies of brewer's yeast.

Microbiogen uses dilute sulphuric acid to break down another component of the plant cell wall: a complex polymer called hemicellulose, which binds cellulose microfibres together. The hemicellulose separates into its chief building block, a sugar called xylose, which can then be washed away with hot water. The process was developed by the National Renewable Energy Laboratory in Golden, Colorado.

The xylose does not go unused, however. Microbiogen has spent a decade developing a strain of brewer's yeast, Saccharomyces cerevisiae, for the fermentation stage that is unique in being the only non-genetically modified strain able to thrive on xylose as well as glucose. As such, the yeast is suitable for use in GM-free foods.

Around one-third of the yeast grown on the xylose is used in fermentation, while the remaining two-thirds can be harvested and used for animal or human food production. "This means we potentially get about 200 litres of ethanol plus 80 to 90 kilograms of excess high-protein yeast per tonne of waste plant material," says Philip Bell of Microbiogen.

The firm plans to cultivate further yeast strains that, as well as producing biofuel, might find uses in wine-making, brewing, baking and health food manufacture. Selling the excess yeast should help to make second-generation biofuels more economical, Bell says. "The conversion of xylose into yeast biomass appears to be at least as valuable, if not more so, than converting it into ethanol," he says.

If he's right, the biofuel industry could soon become known as a food provider rather than an unwelcome consumer.