Scientists Examine Increasing Fuel From Microbes

Biofuel researchers have developed a mechanism that may increase yields for products like diesel, ethanol and even medicines.

Growing bacteria, algae and plants on large scales is challenging enough; getting them to do things they don’t normally do, like make fuel, is even harder.

Scientists have to select and tweak molecular pathways to make cells produce enough useful products to be economically viable. But these modified pathways are fragile, vulnerable to changes in the organism’s environment. These products and their precursors can also be toxic to the cells that produce them.

Take yeast, for instance. The fungus ferments sugar into ethanol, the process used to make wine and beer. However, ethanol, an alcohol, poisons yeast, and even specially bred strains will only tolerate upward of 20 percent alcohol in their environment before they die off.

To make a stronger drink, you have to distill the liquid, which is a very energy-intensive process since it involves boiling and condensing the product.

Engines require a very pure energy source, so a 20 percent fuel concentration just won’t do. However, purifying biological products to usable levels raises production costs beyond what most people will pay for, but with a new molecular control system, researchers expect to engineer more robust microbes and increase biofuel yields, making living organisms a more viable energy source.

read more here in Scientific American