Danish Researchers Process Wheat Straw with Less Energy

Bioprocess engineering researchers from the Technical University of Denmark have reduced the required temperature for hydrothermal pretreatment of wheat straw using a pre-step process that allows the production of organic acids to preserve straw residue.

Production of biofuels from lignocellulosic biomass like wheat straw requires a pretreatment process based on hydrothermal principles of high temperatures (170 to 220 degrees Celsius) in aqueous solution, which is the most energy intensive and most expensive step in biomass conversion.

The Danish research group reported in the journal Biotechnology for Biofuels the beneficial effect of wheat straw ensiling, a well-known method of forage preservation via production of organic acids, as a pre-step process to pretreatment. The group's study sought to subject the wheat straw to 4-week ensiling facilitated by the addition of xylose and lactic acid bacteria for production organic acids prior to hydrothermal pretreatment. Results showed evidences of polysaccharide preservation with ensiling. Data on sugar yield after enzymatic breakdown of the solid fractions from ensiled and non-ensiled wheat straw showed the significant positive efect of ensiling, especially at the lower temperatures of 170 and 180 degrees Celsius.

The group concluded that ensiling potentially enables a considerable reduction in energy consumption during hydrothermal pretreatment of wheat straw, thereby making the production of biofuels from these materials more economically viable.