The potential of fiber-depleted starch concentrate produced through air currents assisted particle separation of barley flour in bio-ethanol production

•A novel biorefining strategy is proposed to co-produce ethanol and β-glucan.•Starch concentrate generated from β-glucan production can be fermented to ethanol.•Hydrolysis of starch concentrate to fermentable sugars requires only STARGEN™ 002.•Fermentation of starch concentrate only requires a 0.25X dose of STARGEN™ 002. Isolation of fiber concentrate enriched in β-glucan from barley flour via air currents assisted particle separation (ACAPS) generates an underutilized by-product stream, starch concentrate. Since barley starch concentrate (BSC) is depleted in soluble fibre, we examined the enzyme requirements for its hydrolysis and subsequent fermentation. Lower doses of a common raw starch hydrolyzing enzyme (STARGEN™ 002) effectively hydrolyzed BSC, achieving similar hydrolysis kinetics to the wheat benchmark. Hydrolysis of BSC did not require further enzyme supplementation, which is required for optimal wheat hydrolysis. This likely resulted from the smaller particle size of BSC relative to wheat feedstocks. Interestingly, simultaneous saccharification and fermentation of BSC using a 0.25X dose of STARGEN™ 002 alone enabled efficient ethanol production, though a requirement for phosphorus supplementation was identified. This study proposes a biorefining strategy that supports the generation of a value-added co-product, starch concentrate, while significantly reducing the enzyme requirements for bioethanol production.