Department of Agricultural and Biological Engineering, 221 Agricultural Engineering Building, Pennsylvania State University, University Park, PA 16802, USA.
The Huck Institutes of Life Sciences, Pennsylvania State University, University Park, PA 16802, USA.
Molecules. 2021 May 16;26(10):2960. doi: 10.3390/molecules26102960.
The lignocellulosic biomass is comprised of three major components: cellulose, hemicellulose, and lignin. Among these three, cellulose and hemicellulose were already used for the generation of simple sugars and subsequent value-added products. However, lignin is the least applied material in this regard because of its complex and highly variable nature. Regardless, lignin is the most abundant material, and it can be used to produce value-added products such as lignin-modifying enzymes (LMEs), polyhydroxyalkanoates (PHAs), microbial lipids, vanillin, muconic acid, and many others. This review explores the potential of lignin as the microbial substrate to produce such products. A special focus was given to the different types of lignin and how each one can be used in different microbial and biochemical pathways to produce intermediate products, which can then be used as the value-added products or base to make other products. This review paper will summarize the effectiveness of lignin as a microbial substrate to produce value-added products through microbial fermentations. First, basic structures of lignin along with its types and chemistry are discussed. The subsequent sections highlight LMEs and how such enzymes can enhance the value of lignin by microbial degradation. A major focus was also given to the value-added products that can be produced from lignin.
纤维素、半纤维素和木质素。在这三种成分中，纤维素和半纤维素已经被用于生成简单糖和随后的增值产品。然而，木质素是在这方面应用最少的材料，因为它的性质复杂且高度可变。尽管如此，木质素是最丰富的材料，它可以用于生产增值产品，如木质素修饰酶（LMEs）、聚羟基烷酸酯（PHAs）、微生物油脂、香草醛、衣康酸和许多其他产品。本综述探讨了木质素作为微生物底物生产这些产品的潜力。特别关注了不同类型的木质素以及每种木质素如何在不同的微生物和生化途径中被用于生产中间产物，这些中间产物可以作为增值产品或基础来生产其他产品。本文综述了木质素作为微生物底物通过微生物发酵生产增值产品的有效性。首先，讨论了木质素的基本结构及其类型和化学性质。随后的部分强调了木质素修饰酶（LMEs）以及这些酶如何通过微生物降解来提高木质素的价值。还重点关注了可以从木质素生产的增值产品。
