Transforming lignocellulosic biomass into C5 and C6 sugars suitable to produce biofuels, building blocks, and high-value-added compounds is a key aspect of sustainable strategies and is central to the biorefinery concept. Xylan is found acetylated and bound to cellulose and lignin forming an insoluble complex in nature, and its degradation involves a collection of enzymes acting together. To gain a better understanding of this process, the present study focuses on the elucidation of the main products resulting from the hydrolysis of delignified Eucalyptus dunnii bark by an enzymatic extract from Pseudozyma sp. with xylanase and acetylxylan esterase activities but no cellulase activity. Scanning electron microscopy (SEM) studies of the insoluble fraction after hydrolysis revealed cracking on the surface of the material. The enzymatic activity of the crude yeast extract was evidenced by TLC and HPLC analysis of the hydrolysate, which allowed us to detect xylose, acetylxylobiose, and acetic acid. Finally, the principal low molecular weight products obtained from this process were characterized by nuclear magnetic resonance (NMR) spectroscopy as xylose and 3-O-acetylxylobiose. Based on these spectroscopic and chromatographic results, it was possible to estimate a 4:1 ratio of xylose to 3-O-acetylxylobiose. These results highlight the importance of using an enzymatic system for effective xylan degradation.

将木质纤维素生物质转化为适合生产生物燃料，构件和高附加值化合物的C5和C6糖，这是可持续战略的关键方面，也是生物精炼概念的核心。发现木聚糖被乙酰化并结合到纤维素和木质素上，形成自然界中的不溶性复合物，其降解涉及一系列共同起作用的酶。为了更好地了解这一过程，本研究着重于阐明假单胞菌酶提取物水解脱木质桉树皮的主要产物。sp。具有木聚糖酶和乙酰木聚糖酯酶活性，但没有纤维素酶活性。水解后的不溶级分的扫描电子显微镜（SEM）研究表明，材料表面开裂。通过水解产物的TLC和HPLC分析证明了粗酵母提取物的酶活性，这使我们能够检测木糖，乙酰基次糖和乙酸。最后，由该方法获得的主要的低分子量产物通过核磁共振（NMR）光谱表征为木糖和3- O-乙酰基木糖。根据这些光谱和色谱结果，可以估计木糖与3- O的比例为4：1-乙酰基木糖。这些结果突出了使用酶促系统有效降解木聚糖的重要性。