In this work, a sustainable and environmental friendly strategy for the biotechnological production of xylitol was proposed and optimized. For this purpose, corn cob was hydrothermally pretreated at high solid loadings (25%) for an efficient solubilization of xylan in hemicellulose derived compounds, xylooligosaccharides and xylose. Xylose enriched streams were obtained from the enzymatic saccharification of the whole slurry (solid and liquid fraction) resulting from the autohydrolysis pretreatment. The xylitol production in a simultaneous saccharification and fermentation (SSF) process, by the recombinant Saccharomyces cerevisiae PE-2-GRE3 strain, was optimized using different enzyme and substrate (pretreated corn cob solid) loadings by an experimental design. This study demonstrated a significant effect of substrate loading on the production process achieving a maximal concentration of 47 g/L with 6.7 % of pretreated corn cob and 24 FPU/g of enzyme loading, with partial detoxification of the hydrolysate. Furthermore, the 1.42-fold increase in xylitol titer and 1.56-fold increase in productivity achieved in a SSF using an acetic acid free-hydrolysate evidenced the negative effect of acetic acid on the yeast-based xylitol production process. The combination of these green technologies and the optimization of the proposed strategy enhanced the overall xylitol production through the valorization of corn cob.

在这项工作中，提出并优化了生物技术生产木糖醇的可持续性和环境友好型策略。为此，玉米芯在高固体含量（25％）下进行水热处理，以使木聚糖有效地溶于半纤维素衍生的化合物，木寡糖和木糖中。通过自水解预处理产生的整个浆液（固体和液体部分）的酶促糖化作用获得了富含木糖的物流。重组酿酒酵母在同时糖化和发酵（SSF）过程中生产木糖醇通过实验设计，使用不同的酶和底物（预处理的玉米芯固体）负载优化了PE-2-GRE3菌株。这项研究表明底物负载对生产过程具有显着影响，最大浓度为47 g / L，预处理玉米芯为6.7％，酶负载为24 FPU / g，且水解产物部分排毒。此外，在使用乙酸游离水解物的SSF中，木糖醇滴度提高了1.42倍，生产率提高了1.56倍，这证明了乙酸对基于酵母的木糖醇生产过程的负面影响。这些绿色技术与拟议策略的优化相结合，通过玉米芯的增值提高了木糖醇的整体产量。