Efficiency boost for straw based biofuel production

Scientists from the University of Hong Kong have developed a new strategy to enhance the efficiency of rice straw for biofuel production.

Significantly, the authors of the study detailing the breakthrough claim the strategy can also be used to boost efficiency of biofuel production from other cereals like maize, wheat, and barley.

As biofuel demand has rocketed in recent years, cellulose from non-edible plant materials has been increasingly used in bioethanol production. The cross-linking of lignin in plant cell walls however, makes it expensive and complicated to release glucose from cellulose during bioethanol production.

The collaborative effort between the University of Hong Kong and Kyoto University has unveiled a new strategy to allow cellulose in rice straw to release its fermentable sugar more efficiently. The team discovered that when flavone synthase II (FNSII), a key enzyme involved in tricin synthesis, is knocked out, not only is tricin not produced, but the lignin content in rice straw was also reduced by approximately one-third. In addition, the yield of glucose from cellulose degradation was increased by 37% without any chemical treatment.

HKU plant biochemists Clive Lo Sze-chung and his student Lydia Lam Pui-ying, together with Kyoto University lignin specialist Yuki Tobimatsu, started their study two years ago. The results have now been published in the journal Plant Physiology.

"This is the first demonstration of the reduction of cell wall lignin content in rice straw by the disruption of tricin production," said Clive Lo, "Importantly, there are no negative impacts on rice growth and productivity." As plants in the grass family all contain tricin-bound lignin, this strategy can be applied to other cereals like maize, wheat, and barley as well as grass species (e.g. sorghum and switchgrass) cultivated around the world exclusively for ethanol production, so that they can be utilized more efficiently as raw materials for biofuel.”