Truth about Ethanol

Fermentation using bacteria

Yeast is very good at converting glucose, and other six-carbon sugars into ethanol. Unfortunately, a significant proportion of waste biomass consists of complex natural polymers made from sugars that are not "digested" readily by yeast enzymes.

These include hemicellulose, which on hydrolysis produces a range of sugars including: mannose, xylose, arabinose and galactose, depending on the original source.

KO11

A genetically modified bacterium, developed by the microbiologist Lonnie Ingram in 1987, has enabled these sugars to be converted to ethanol. The bacterium, referred to as KO11, would normally produce acids, but the modification means ethanol is produced instead.



 The advantage over yeast is that a wider range of sugars can be processed, enabling the utilisation of biomass waste such as wood waste, corn stalks, rice hulls, and other organic waste, which would otherwise require disposal by some other method, or which could only be partially utilised by conventional fermentation methods, making them uneconomic.

 

 

Commercial Development
The BC International Corporation is attempting to develop this approach commercially in the United States, focusing on:

• areas where legislation prohibits burning of agricultural waste
• conventional ethanol plants suitable for conversion and refurbishment

 

Ethanol itself is also used:

• As a solvent in manufacture of perfumes, cosmetics, pharmaceuticals, varnishes, detergents, inks and coatings
• As a motor fuel and motor fuel blending agent (link to fuel section - when written)
• Ethanol is an intermediate in the manufacture of many products.

Ethanol is also present in many common beverages. Synthetic alcohol is not normally used for this purpose as it may contain traces of other by-products of manufacture.

The Biofuel

 A growing industry has been investigating fossil-fuel alternatives for decades, and much of their research focuses on biofuels -- petroleum substitutes made from natural plant oils. In some cases, pure, unaltered vegetable oil can power standard diesel engines; after all, Rudolph Diesel originally designed the engine that bears his name in an attempt to give farmers the ability to operate equipment using locally grown fuel.

But pure vegetable oil, while certainly a biofuel, has limitations. The glycerine in natural oils increases their viscosity, making them solidify in cold temperatures; think about what happens to bacon grease if left in the refrigerator. This could be bad news for the fuel lines, filters and injectors on an engine in Alaska, for example.

Chemists have a pair of solutions to this problem. Some plants, such as corn, contain sugars that, when fermented like beer and liquor, produce ethanol, an alcohol that can be used as fuel. Ethanol is frequently used as a smog-reducing additive in gasoline.

Other plants, such as soybeans, are better used to produce biodiesel. In this process, a catalyst is mixed into the oil, separating the glycerine from the oil's fatty acid alkyl esters . With the glycerine gone, biodiesel can run most diesel engines with less fouling and cold-weather problems.
Bio-fuel infrastructure is still under development in many parts of the world, and the processes to produce some types of bio-fuel are not yet efficient enough to justify large-scale production But the need to find a more environmentally friendly alternative to fossil fuels means that, sooner or later, the fuel in your gas tank will have a lot in common with what's on your plate.

Palm oil is a major crop in Southeast Asia. As demand increases for palm oil to produce biodiesel, plantations in countries like Malaysia and Indonesia are clearing vast swaths of rainforest to make room for more oil-producing palms. And the trucks, ships and production facilities used to move palm oil from these countries to the car- and truck-heavy West add to the fuel burned -- and emissions produced -- to bring this green fuel to market. Palm oil is not the only bio-fuel facing this dilemma, but its popularity and low cost mean it's encountered the problem on a wider, and more public, scale than many of the edible fuels.