It is the hunt for cost effective biofuel processes that has driven the quest to find faster and more efficient biological processes. Biofuels are fuel that is produced through a biological process; one such method is taking plant material and turning it into bioethanol. For this a catalyst is required and enzymatic based catalysts have proved to be very efficient.
Bioethanol is a type of alcohol made by fermentation. It derives mostly from carbohydrates produced in sugar or starch crops such as corn, sugarcane, or sweet sorghum. For this a cellulosic biomass is needed, and the conversion process requires an enzyme usually of microbial origin.
The generation of enzymatic catalysts is addressed by the new research. A common way to produce enzymes is by using fungi. However, fungi can be difficult to handle and they are often slow. To overcome this, researchers have taken a common fungus called Aspergillus niger and cultured it so that it has mutated into a form that is more efficient for enzyme production.
The fungus produces an enzyme (called β-1,4-endoxylanase) that is capable of breaking down hemicellulose (these are the complex carbohydrates in plant material.) The mutated form of the fungus was created by carefully subjecting different strains of the fungus to gamma radiation.
The mutated form of the fungus was able to produce quantities of the enzyme at twice the rate that an unmutated form of the fungus could generate. The mutated form also produced pellets of the enzyme that were smaller and more concentrated, making them easier to handle.
Further research is now underway to see how the mutated fungus can be used on an industrial scale.
The mutations were produced by Jin Chuan Wu of the A*STAR Institute of Chemical and Engineering Sciences. The findings have been published in the Biochemical Engineering Journal, in a paper headed “Improved endoxylanase production and colony morphology of Aspergillus niger DSM 26641 by γ-ray induced mutagenesis.”
