The introduction of enzymes as catalysts into synthetic organic che-mistry opened access to many new and highly enantioselective trans-formations. Baeyer-Villiger oxidation using biocatalysts represents a powerful methodology for the one-step asymmetric synthesis of chiral lactones. Due to a large number of different Baeyer-Villiger mono-oxygenases (BVMOs) with so far unknown biocatalytic properties the development of an efficient screening methodology based on micro-scaled whole-cell biotransformations became mandatory. The fermen-tation optimization of whole-cell mediated Baeyer-Villiger oxidation was the next logical step. A two-in-one in situ substrate feeding and product removal concept (SFPR) using an adsorbent resin and a recombinant E.coli strain was elaborated. Several critical parameters of the fermentation process were optimized. This work spans from biocatalyst assignment within screening protocols to up-scaling of the process to, ultimately, applying this biotransformation in the synthesis of natural compounds. This book is a very valuable contribution to the scientific community especially for people which are interested in the field of applied bio-catalysis.