Zoghlami Aya, Paës Gabriel
FARE Laboratory, INRAE, University of Reims Champagne-Ardenne, Reims, France.
Front Chem. 2019 Dec 18;7:874. doi: 10.3389/fchem.2019.00874. eCollection 2019.
Lignocellulosic biomass (LB) is an abundant and renewable resource from plants mainly composed of polysaccharides (cellulose and hemicelluloses) and an aromatic polymer (lignin). LB has a high potential as an alternative to fossil resources to produce second-generation biofuels and biosourced chemicals and materials without compromising global food security. One of the major limitations to LB valorisation is its recalcitrance to enzymatic hydrolysis caused by the heterogeneous multi-scale structure of plant cell walls. Factors affecting LB recalcitrance are strongly interconnected and difficult to dissociate. They can be divided into structural factors (cellulose specific surface area, cellulose crystallinity, degree of polymerization, pore size and volume) and chemical factors (composition and content in lignin, hemicelluloses, acetyl groups). Goal of this review is to propose an up-to-date survey of the relative impact of chemical and structural factors on biomass recalcitrance and of the most advanced techniques to evaluate these factors. Also, recent spectral and water-related measurements accurately predicting hydrolysis are presented. Overall, combination of relevant factors and specific measurements gathering simultaneously structural and chemical information should help to develop robust and efficient LB conversion processes into bioproducts.
木质纤维素生物质（LB）是一种丰富的可再生植物资源，主要由多糖（纤维素和半纤维素）和一种芳香聚合物（木质素）组成。LB作为化石资源的替代品具有很高的潜力，可用于生产第二代生物燃料以及生物源化学品和材料，同时不会影响全球粮食安全。LB增值的主要限制之一是其对酶水解的抗性，这是由植物细胞壁的异质多尺度结构引起的。影响LB抗性的因素紧密相连且难以区分。它们可分为结构因素（纤维素比表面积、纤维素结晶度、聚合度、孔径和孔体积）和化学因素（木质素、半纤维素、乙酰基的组成和含量）。本综述的目的是对化学和结构因素对生物质抗性的相对影响以及评估这些因素的最先进技术进行最新综述。此外，还介绍了最近能准确预测水解的光谱和与水相关的测量方法。总体而言，结合相关因素以及同时收集结构和化学信息的特定测量方法，应有助于开发出强大而高效的将LB转化为生物产品的工艺。
