London: Straw from crops such as wheat, barley, and oats is seen as a potential source of biomass for second generation biofuel production. With new findings, scientists have now come closer to making the production more efficient.
Researchers at the Institute of Food Research in Britain looked at the steps needed to unlock the sugars tied up in the tough straw structure.
They discovered the key factors that determine the efficiency of saccharification - the process that converts enzymes into glucose.
"The sugars in the straw are in a form that makes them inaccessible to the enzymes that release them for conversion into biofuels, so pre-treatments are needed," the researchers said.
The pre-treatments make the complex carbohydrates more accessible to enzymes that convert them to glucose which is then fermented by yeast into ethanol.
In the pre-treatment stage, the researchers focused on steam explosion, which involves ‘pressure-cooking’ the biomass, to drive a number of chemical reactions.
A rapid pressure-release then causes the material to be ripped open, to further improve accessibility.
They varied the temperature and duration of steam explosion and then used a variety of physical and biochemical techniques to characterise what effects varying the pre-treatments had on the different types of sugars before and after saccharification.
The amount of cellulose converted to glucose increased with the severity of the pretreatment.
Saccharification efficiency is also associated with the loss of specific sugars, and subsequent formation of sugar breakdown products.
In a further study, the scientists discovered the key factors that determine the efficiency of saccharification.