Polysaccharide depolymerization is an essential step for valorizing lignocellulosic biomass. In inexpensive systems such as pure water or dilute acid mixtures, carbohydrate monomer degradation rates exceed hemicellulose—and especially cellulose—depolymerization rates at most easily accessible temperatures, limiting sugar yields. Here, we use a reversible stabilization of xylose and glucose by acetal formation with formaldehyde to alter this kinetic paradigm, preventing sugar dehydration to furans and their subsequent degradation. During a harsh organosolv pretreatment in the presence of formaldehyde, over 90% of xylan in beech wood was recovered as diformylxylose (compared to 16% xylose recovery without formaldehyde). The subsequent depolymerization of cellulose led to carbohydrate yields over 70% and a final concentration of ~5 wt%, whereas the same conditions without formaldehyde gave a yield of 28%. This stabilization strategy pushes back the longstanding kinetic limits of polysaccharide depolymerization and enables the recovery of biomass-derived carbohydrates in high yields and concentrations.

多糖解聚是增值木质纤维素生物质的必不可少的步骤。在诸如纯水或稀酸混合物之类的廉价系统中，在最容易达到的温度下，碳水化合物单体的降解速率超过半纤维素（尤其是纤维素）的解聚速率，从而限制了糖产量。在这里，我们使用甲醛与乙缩醛形成可逆稳定的木糖和葡萄糖，以改变这种动力学范式，防止糖脱水成呋喃并随后降解。在甲醛存在下进行苛刻的有机溶剂预处理期间，山毛榉木中90％的木聚糖被回收为二甲酰基木糖（相比之下，不含甲醛的木糖回收率为16％）。随后的纤维素解聚导致碳水化合物收率超过70％，最终浓度约为5 wt％，而在无甲醛的相同条件下，收率为28％。这种稳定化策略推翻了多糖解聚的长期动力学极限，并能够以高收率和高浓度回收生物质衍生的碳水化合物。