Bioethanol production from barley hull using SAA (soaking in aqueous ammonia) pretreatment

摘要: Abstract Barley hull, a lignocellulosic biomass, was pretreated using aqueous ammonia, to be converted into ethanol. hull soaked in 15 and 30 wt.% ammonia at 30, 60, 75 °C for between 12 h 11 weeks. This pretreatment method has been known as “soaking ammonia” (SAA). Among the tested conditions, best conditions observed were 75 °C, 48 h, 15 wt.% 1:12 of solid:liquid ratio resulting saccharification yields 83% glucan 63% xylan with FPU/g-glucan enzyme loading. Pretreatment 24–72 h removed 50–66% original lignin from solids while it retained 65–76% without any loss. Addition xylanase along cellulase resulted synergetic effect on ethanol production SSCF (simultaneous co-fermentation) SAA-treated barley recombinant E. coli (KO11). With 3% w/v loading 4 mL loadings, SAA treated 24.1 g/L concentration FPU cellulase/g-glucan loading, which corresponds 89.4% maximum theoretical yield based xylan. SEM results indicated that treatment increased surface area pore size. It is postulated these physical changes enhance enzymatic digestibility hull.