School of Pharmaceutical Sciences (FCF), Department of Bioprocesses and Biotechnology, São Paulo State University (UNESP), Araraquara, SP, 14800-903, Brazil.
School of Pharmaceutical Sciences (FCF), Department of Food and Nutrition, São Paulo State University (UNESP), Araraquara, SP, 14800-903, Brazil.
Appl Biochem Biotechnol. 2020 Jan;190(1):197-217. doi: 10.1007/s12010-019-03076-0. Epub 2019 Jul 19.
Eucalyptus wood is the primary source of fibers to produce paper and cellulose in South American countries. The major by-product generated in the cellulose industry is sawdust derived from chip wood production, which is designated as Eucalyptus by-product (EB). The xylooligosaccharides (XOS) are xylose-based oligomers with proven effects over maintenance and stimulation of beneficial human gut bacteria. This study reported the EB extraction and characterization along with an assessment of hemicellulose hydrolysis using commercial xylanases to produce XOS. Hemicellulose derived from extracted and NaClO pretreated (HEEBPT) presented xylan content of 55%, which was similar to 58.5% found in commercial Birchwood hemicellulose (CBH). The enzymatic hydrolysis of HEEBPT and CBH presented 30% as maximum conversion of xylan into XOS without significant difference among the enzymatic extracts evaluated. The XOS production from EB was proven as a technically feasible alternative to recover a value-added product from hemicellulosic fraction generated in the cellulose industry. However, lignin removal with NaClO from EB affects the feasibility of an industrial process because they generate toxic compounds in the pretreatment step. Thus, further studies with alternative reagents, such as ionic liquids, are required to asses selectively lignin removal from EB. Graphical Abstract.
桉树木材是南美洲生产纸张和纤维素的主要纤维来源。纤维素工业产生的主要副产物是木屑，来自木片生产，被指定为桉树副产品 (EB)。木二糖（XOS）是基于木糖的低聚物，已被证明对维持和刺激有益的人类肠道细菌有效果。本研究报告了 EB 的提取和特性，以及使用商业木聚糖酶水解半纤维素以生产 XOS 的评估。从提取和 NaClO 预处理的（HEEBPT）中获得的半纤维素具有 55%的木聚糖含量，与商业白桦木半纤维素（CBH）中发现的 58.5%相似。HEEBPT 和 CBH 的酶水解在没有评估的酶提取物之间没有显着差异的情况下，将木聚糖最大转化为 30%的 XOS。从 EB 生产 XOS 被证明是从纤维素工业中产生的半纤维素部分回收增值产品的技术可行的替代方案。然而，EB 中的 NaClO 去除木质素会影响工业过程的可行性，因为它们在预处理步骤中会产生有毒化合物。因此，需要使用离子液体等替代试剂进行进一步研究，以评估从 EB 中选择性去除木质素。
