Impact of triticale cultivar (× Triticosecale sp. Wittmack) and location on pretreatment requirements and fermentable sugars yield

Abstract

Triticale, a man-made grain cereal developed by crossing wheat with rye and displaying high straw yield, has gained interest for second-generation fuel ethanol. This study aimed at assessing variability in straw properties from triticale cultivars grown in South Africa and their impact on straw processability for optimal yield of total fermentable sugars (TFS) from dilute acid pretreatment followed by enzymatic hydrolysis. Response surface methodology (RSM) was applied to maximize the total fermentable sugars yield from dilute acid pretreatment–enzymatic hydrolysis. The optimum pretreatment conditions 182 °C—0.39% (w/w)—15.4 min maximized total sugar yield at 50.5 g/100 g for straw from cultivar 01T43 (1.2% ash), representing total sugars recovery of 80.4% of theoretical TFS (xylose + glucose) in the straws. Conditions of 189 °C—0.60%—18 min and 190 °C—0.53%—13 min maximized total sugar yield for cultivars 00T207 (5.8% ash) and BACCHUS (4.4% ash) at 46.7 and 44.9 g/100 g which represented total sugars recoveries of 77.8 and 68% of theoretical TFS (xylose + glucose) in the straws, respectively. Enhancement of sugar yield from triticale straw is possible by dilute acid pretreatment optimization, coupled with selection of cultivars with low ash content in straw for reduced pretreatment requirements.