ABSTRACT
Yutaka Tamarua,b,c and Roy H. DoidaDepartment of Life Science, Graduate School of Bioresourses, bDepartment of Bioinformatics, Life Science Research, cLaboratory of Applied Biotechnology, Industrial Technology Innovation Institute, Mie University, 1577 Kurimamachiya, Tsu, Mie 514-8507, JapandDepartment of Molecular and Cellular Biology, University of California, Davis, One Shields Avenue, Davis, California 95616, USA ytamaru@bio.mie-u.ac.jp
1 INTRODUCTION20.The plant cell wall, which plays a crucial role in apoplastic diffusion of water and ions and protects the internal protoplast, is one of the major barriers that protect plants against pathogens. Cell walls comprise a middle lamella, the outermost part of the wall, shared by adjacent cells. A primary wall is laid down internally to the middle lamella, and when cell enlargement ceases, a secondary wall may form. On the other hand, among potential alternative bioenergy resources, plant biomass has been identified as the prime source of biofuels and other biorefinery products. Lignocelluloses as agricultural, industrial,
and forest residuals from the plants account for the majority of the total biomass present in the world. As far as we can use the biomass efficiently, we will convert the production of industrially important products from oil refinery to biorefinary. Therefore, bioconversion of the lignocellulosic components into fermentable sugars would be essential for biorefinery products. In nature, a variety of microorganisms including bacteria and fungi have the ability to degrade the lignocellulosic biomass to C-5 and/or C-6 sugars. Moreover, new concepts have been proposed to enable the overall goal of cost reduction, including genetically modifying the cell wall composition of energy crops in order to make their conversion easier, and combining the processes of glycoside hydrolase (GH) enzyme production, saccharification, and fermentation (consolidated bioprocessing: CBP). In this chapter, we review our recent understanding of the strategies for degrading the plant cell walls, associated microbial communities, and enzymes, and the interactions and correlations between them. Perspectives and suggestions are given in the context of improving microbial efficiency in carbon utilization and utilizing both endophytic and saprotrophic microorganisms with the overall goal of producing cost-effective biofuels from biomass.
