Foreword

Today’s chemical technology is still strongly dependent on fossil starting materials, fuel production being only one but a dominant example. Yet environmental concerns and political constraints have put the replacement of fossil carbon sources in industrial processes by compounds that are available in even larger amounts, but whose utilization can be performed in a carbon dioxide neutral way, at a top place in the list of technological advances of the 21^st century. Quantitatively, this requirement can only be fulfilled by plant biomass since plants use carbon dioxide fixation via photosynthesis as the sole source of carbon. Furthermore, the dry plant biomass consists mainly of three polymers (cellulose, hemicelluloses and lignin), which – after depolymerization to the monomer constituents (hexoses, pentoses and phenylpropan substances) – can be used as a basis for the industrial production of ethanol or platform chemicals by fermentation or biocatalysis (biorefinery). Clearly, the production of these monomeric constituents by reliable processes and in high amounts that satisfy economic requirements and avoiding the production of hazardous byproducts is essential to the biorefinery concept. There is general consent that this can only be achieved by enzymatic hydrolysis.

Yet biological processes are slow on technological scales. Therefore, the composition of the enzymes used, their properties and the kinetics of the hydrolysis process are still major areas which need improvement and optimization. To do this on a science-driven basis, however, more basic knowledge is needed. Almost all of the enzymes used are derived from fungi. Fungi, the fifth kingdom, play a predominant role in the degradation of lignocellulose biomass in nature, and consequently some of them have therefore served as models or workhorses for the production of the respective enzymes for plant biomass hydrolysis in academic laboratories and on an industrial scale. This book therefore presents an overview of the progress and latest achievements in the understanding of these processes at genomic, transcriptomic and proteomic levels which are indispensable prerequisites for further improvement of the process, and highlights areas for further research development.