Industrial Biotechnology & Biocatalysis Group, Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens, 9 Iroon Polytechniou Str., Zografou Campus, Athens 15780, Greece.
Chemical Process and Energy Resources Institute (CPERI), CERTH, 6(th) km Harilaou-Thermi Road, 57001, Thermi, Thessaloniki, Greece.
Bioresour Technol. 2018 Dec;270:208-215. doi: 10.1016/j.biortech.2018.09.018. Epub 2018 Sep 4.
Ethanol production at high-gravity promise to achieve concentrations over the threshold for an economical distillation process and concurrently reduce water consumption. However, a persisting limitation is the poor mass transfer conditions resulting in low ethanol yields and concentrations. Hereby, the combination of an acetone/water oxidation pretreatment process (AWO) with a liquefaction/saccharification step, using a free-fall mixer, before simultaneous saccharification and fermentation (SSF) can realize ethanol concentrations of up to ca. 74 g/L at a solids content of 20 wt%. The free-fall mixer achieved a biomass slurry viscosity reduction by 87% after only 2 h of enzymatic saccharification, indicating the efficiency of the mixing system. Furthermore, the direct enzymatic treatment of AWO pretreated corn stover (CS) by a GH11 recombinant xylanase, led to the production of xylooligosaccharides (XOS) with prebiotic potential and the removal of insoluble fibers of hemicellulose improved the glucose release of AWOCS by 22%.
在高浓度下生产乙醇有望达到经济蒸馏过程的阈值，并同时减少用水量。然而，一直存在的限制是传质条件差，导致乙醇产率和浓度低。在这里，在同步糖化发酵（SSF）之前，使用自由落体混合器，将丙酮/水氧化预处理过程（AWO）与液化/糖化步骤结合，可以在 20wt%的固体含量下实现高达约 74g/L 的乙醇浓度。自由落体混合器在仅 2 小时的酶糖化后，将生物质浆料的粘度降低了 87%，表明混合系统的效率很高。此外，通过 GH11 重组木聚糖酶直接处理 AWO 预处理的玉米秸秆（CS），产生了具有益生元潜力的木低聚糖（XOS），并去除了不溶性半纤维素纤维，使 AWOCS 的葡萄糖释放提高了 22%。
