Page 24 - Cascade biocatalysis

XXII Preface

(PGC #7). Inherently, enzymes are biodegradable (PGC #10) and innocuous to
the environment (PGC #3), not the least because they operate in water as a safe
solvent (PGC #5) at ambient temperature and pressure, which minimizes energy
consumption (PGC #6).
Cascade Biocatalysis is an effort to imitate the style of chemical conversions
occurring in living beings, which are totally different from the traditional use
of single enzymes by synthetic chemists in the laboratory for catalyzing isolated
transformations. Instead, cells apply multistep synthetic strategies, catalyzed by
several enzymes acting sequentially along a pathway, in which a product formed
in one reaction in situ becomes the substrate of the next catalyst. This is possible
because of the very similar mild reaction conditions under which most enzymes
operate, which facilitates their combination and allows effective strategies of
reaction engineering, for example, to shift unproductive equilibria by coupling to
thermodynamically favored processes for overall high conversion and economic
efficiency.
This concept has recently been recognized as the major focus for a series of
international symposia on Multistep Enzyme-Catalyzed Processes, the last symposium
having just been celebrated in Madrid in April 2014. Research in this area
has also been coordinated within the activities of the European Union funded
COST network CM0701 entitled Cascade Chemoenzymatic Processes – New Synergies
Between Chemistry and Biochemistry (2008–2012; http://www.cost-cascat.polimi.it).
This handbook brings together contributions from scientists deeply involved in
the activities of this COST action as well as complementary chapters on related
research from additional authors, who are well known for their seminal work in this
contemporary research field. The topics covered in the chapters span from examples
related to integrated applications of cofactor-dependent oxidoreductases to the
exploitation of transferases; from the multistep modification of the nitrile functional
group to the synthesis of complex carbohydrates; and from developments of new
dynamic kinetic resolution processes to intricate examples of chemoenzymatic
multistep one-pot procedures.
We would like to thank all the authors who, despite their busy schedules, have
participated in this project to share their expertise with the future readers of
this book. Thanks are also due to Elke Maase and Stefanie Volk at Wiley-VCH
Publishers, for their careful editorial support and for their continuous goad in
order to meet assigned deadlines.
Finally, we hope that our readers will find this volume useful as a stimulating
source of ideas for their own research and/or teaching activities.

Sergio Riva
Wolf-Dieter Fessner