Integrated processing of sugarcane bagasse: Arabinoxylan extraction integrated with ethanol production

Abstract

A proof-of-concept project compared extraction of arabinoxylans (AX) from sugarcane bagasse and wheat bran via alkaline hydrogen peroxide followed by enzyme-assisted extraction with combinations of feruloyl esterases and a xylanase. Bagasse contains comparable amounts of AX to wheat bran, but with a much lower arabinoxylan substitution on the xylan backbone (A:X ratio of around 0.2 compared with 0.6 for wheat bran), hence offering AX products with distinctive functionality and potential end uses. In the current work, bagasse released its AX more readily than wheat bran, and released a wider range of molecular weights. Use of feruloyl esterase and xylanase enzymes on their own or following alkaline peroxide extraction did not enhance AX release substantially; however, the xylanase appeared to be effective at reducing the size of AX molecules, and there is scope to optimise the effects of enzymes to produce specific AX product fractions. As bagasse frequently arises within the context of bioethanol production, integration of AX extraction with ethanol production could allow economic production of a portfolio of AX products, as has been demonstrated in principle for AX co-production in a wheat ethanol plant.