From plant carbohydrate active enzymes to fungal biotechnologies

Abstract

The plant cell wall (PCW) is the outer coat of plant cells crucial for plant morphology and development. It provides plant structural integrity and resistance to herbivores and pathogens. PCW is composed primarily of cellulose, hemicellulose and pectin, as well as structural proteins, and lignin. Carbohydrate active enzymes, also called CAZYmes, are involved in the development, modification and decomposition of PCW polysaccharides and lignin. Whereas plant transglycosylases are essential for plant growth, development and starvation and modify the major PCW hemicellulose, xyloglucan, fungal CAZYmes, such as lytic polysaccharide monooxygenases (LPMOs) and laccases use diverse mechanisms for the deconstruction of plant polysaccharides and lignin. Their ability to deconstruct or modify recalcitrant lignocellulosic material explains the raising interest in using them for the production of biofuels, for nanotechnologies and green chemistry, and in several industrial applications such as in pulp, paper and wood industry.
The focus of my research is to characterize novel plant and fungal CAZYmes, and provide new insight into PCW structure and PCW deconstruction, at both microscopic and molecular levels. In order to achieve this, protein studies have been backed up by the use of physico-chemical and chromatographic methods, the development of polysaccharide microarrays and dynamic imaging. Thanks to this highly multidisciplinary approach, we were able to better understand mechanisms of PCW remodelling and to unveil synergies between fungal oxido-reductases that are crucial for PCW deconstruction, and to understanding how enzymatic tools available in nature can be used and optimized in view of industrial applications.