Selecting the Best Wheat for Biorefining.

Following the UK Government implementation of the Renewable Transport Fuel Obligation (RTFO) many bioethanol plants have been planned with a total production capacity of 2 million tonnes of bioethanol per year. Apart from the British Sugar plant, which produces only 3 % of the planned capacity from sugar beet, all other plants plan to use wheat as a feedstock.   Wheat has been used for production of potable alcohol in the UK. The production process for bioethanol and potable alcohol are similar.  The experience of the potable alcohol industry indicates that wheat samples vary in their alcohol yielding potential and ease of processing.  Based on this, the potable alcohol industry has Recommended List (RL) varieties for distilling quality. An economic study conducted on 83 samples from these RL varieties indicated that, good quality bioethanol wheat against a poor one saves about $45 million per year in a plant with a production capacity of 100,000 tonnes of wheat per year. Poor bioethanol wheat not only yields less ethanol but also requires more energy for processing.   Good quality wheat is therefore crucial for the economics as well as the greenhouse gas saving of bioethanol production.  The objective of this study is to determine quality criteria for bioethanol wheat.   Several biochemical and physical features of 83 RL samples grown in two consecutive years across several sites were studied. Among all the studied parameters, grain protein and thousand grain weight (TGW) appeared to be the best indicator of ethanol yield.   A model based on a combination of grain protein and TGW explained 67% of the variation in ethanol yield.  When site and variety were included, this model explained 87% of the variation in ethanol yield. Introducing such quality criteria at bio-refinery intake in purchasing wheat grain enhances the economics and reduces environmental impact of the industry.