The effect of wheat genotype on ethanol production from straw and the implications for multifunctional crop breeding Shahin S. Ali a, *, Mojibur Khan a,1 , Ewen Mullins b , Fiona Doohan a, * a Molecular Plant-Microbe Interactions Laboratory, School of Biology and Environmental Science, University College Dublin, Dublin 4, Ireland b Dept. of Crop Science, Teagasc Crop Research Centre, Oak Park, Carlow, Ireland article info Article history: Received 20 December 2011 Received in revised form 17 March 2012 Accepted 21 March 2012 Available online 13 April 2012 Keywords: Cultivar Fusarium Cellulose Biomass Phenolic Consolidated bioprocessing abstract A feasible crop breeding strategy for straw utilisation in the ethanol industry requires an in-depth study of the interaction between the feedstock and the microbial agents during the production process. This study investigated the ethanol yield potential of the straw from nine wheat cultivars through consolidated bioprocessing by two strains of Fusarium oxysporum. Plant parameters assessed were plant lignin, cellulose and phenolic acid content; fungal parameters analysed were biomass and cellulase/xylanase activity. Wheat cultivars varied significantly in the amount of ethanol produced from straw by F. oxy- sporum. Ethanol yielded negatively correlated with the hemicellulose and lignin content of the straw, and the amount of the lignin phenolics syringic acid and coniferyl alcohol. Significant positive correlations were observed between ethanol yield and the activity of the fungal enzymes b-glucosidase and b-xylosidase. If crops such as wheat are to be used for multifunctional purposes, i.e. food and fuel, the assessment of lignocellulose compo- sition and biodegradability must be assessed as part of our crop breeding programmes. ª 2012 Elsevier Ltd. All rights reserved. 1. Introduction Cellulosic ethanol is a renewable energy source produced through fermentation of lignocellulosic waste material. The annual dry lignocellulosic biomass produced from seven major crops, viz. wheat, corn, barley, oat, rice sorghum and sugarcane could replace almost 30% of the gasoline consumed globally [1]. Rice and wheat straw could respectively yield 291 hm 3 and 104 hm 3 per year of ethanol [1]. But, a major bottleneck is the processing costs associated with the production of cellulosic ethanol from agricultural residues. The current technology for cellulosic ethanol production involves several stapes commencing with feedstock pretreatment, hydrolytic enzyme production, saccharification, fermentation and product recovery [2]. But in recent years there has been much research on consolidated bioprocessing (CBP) which involves produc- tion of enzymes, saccharification and fermentation in a one- step process by a single microorganism or a consortium of different organisms, which may aid to overcome the cost barrier [3e5]. Several organisms including the plant- pathogenic fungus Fusarium oxysporum have been shown to facilitate the direct conversion of wheat straw to cellulosic ethanol [6,7] and are effective CBP microorganisms [5]. Though CBP has been extensively researched, there is little information regarding how the ultra-structural and bio- chemical variance within germplasm banks of the lignocel- lulosic feedstock might influence the efficacy of these CBP microorganisms. Obviously the ease with which straw can be degraded will be one of the determining factors regarding the commercial viability and profitability of the cellulosic ethanol * Corresponding authors. Tel.: þ353 17162248; fax: þ353 17161102. E-mail addresses: shahin.ali@ucd.ie (S.S. Ali), fiona.doohan@ucd.ie (F. Doohan). 1 Present address: Institute of Advanced Study in Science and Technology, Guwahati-35, India. Available online at www.sciencedirect.com http://www.elsevier.com/locate/biombioe biomass and bioenergy 42 (2012) 1 e9 0961-9534/$ e see front matter ª 2012 Elsevier Ltd. All rights reserved. doi:10.1016/j.biombioe.2012.03.020