This study presents the upscaling of soda pretreatment of sugarcane bagasse (SB) using a new redox mediator (2-hydroxynaphthalene-1,4-dione) obtained from renewable resources, which does not affect enzymatic hydrolysis and fermentation. Upscaling was performed from a 0.5 L batch static stainless steel reactor to a 20 L pulp digester with forced liquor circulation, analogous to digestors used in the pulp and paper industry. Enzymatic hydrolysis of the pretreated material was optimized using the fed-batch method and was then carried out on a larger scale. The fed-batch method, combined with addition of 1 % (v v−1) Tween 80, enabled the solids load to be increased from 10 % to 15 % (w v−1), with an enzyme load of only 3.00 FPU g−1. This led to a maximum total reducing sugars concentration of ∼142 g L−1 after 72 h of hydrolysis. Co-fermentation of C5 and C6 sugar-rich hydrolysate by a consortium of CERLEV 47 (Saccharomyces cerevisiae) and CERLEV 1015 (Pichia guilliermondii) led to a maximum 2G ethanol production of 61.3 g L−1 (308 L ethanol per ton of SB). Mass and energy balances demonstrated that the combustion of black liquor, a byproduct of the soda pretreatment, could satisfy the energy demands of the pretreatment, enzymatic hydrolysis, and fermentation, with an energy of 21.11 MJ using the surplus SB (80 %) from 1G ethanol production. This finding indicated that the developed process was robust and had the potential to enhance total 2G ethanol production. This study supports the feasibility of an integrated 1G/2G biorefinery by improving energy efficiency, economic viability, and environmental sustainability.

中文翻译：

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甘蔗渣 2G 乙醇生产优化：使用氧化还原介质放大苏打预处理，然后进行补料分批酶解和共发酵


本研究介绍了使用从可再生资源获得的新型氧化还原介质（2-羟基萘-1,4-二酮）对甘蔗渣 （SB） 进行苏打预处理的放大，这不会影响酶水解和发酵。从 0.5 L 间歇式静态不锈钢反应器放大到具有强制液体循环的 20 L 纸浆蒸煮器，类似于纸浆和造纸行业中使用的蒸煮器。使用补料分批法对预处理材料进行酶促水解，然后进行更大规模的处理。补料分批法，结合添加 1 % （v v-1） Tween 80，使固体负荷从 10 % 增加到 15 % （w v-1），酶负荷仅为 3.00 FPU g-1。这导致水解 72 小时后的最大总还原糖浓度为 ∼142 g L-1。由 CERLEV 47（酿酒酵母）和 CERLEV 1015（吉利毕赤酵母）组成的财团对 C5 和 C6 富含糖的水解物进行共发酵，导致最大 2G 乙醇产量为 61.3 g L-1（每吨 SB 308 L 乙醇）。质量和能量平衡表明，苏打预处理的副产品黑液的燃烧可以满足预处理、酶解和发酵的能量需求，使用 1G 乙醇生产中剩余的 SB （80%） 的能量为 21.11 MJ。这一发现表明，开发的工艺是稳健的，并且有可能提高 2G 乙醇的总产量。本研究通过提高能源效率、经济可行性和环境可持续性来支持 1G/2G 综合生物精炼厂的可行性。