Strain engineering strategies for improving whole-cell biocatalysis: engineering Escherichia coli to overproduce xylitol as an example.

This chapter provides an overview of key tools and methodologies available to practitioners of biocatalysis interested in using microorganisms to carry out biotransformations and describes specific examples of applying genetic modification strategies for strain design. We focus on the use of the polymerase chain reaction (PCR) for gene amplification, plasmid DNA for recombinant gene cloning and expression, and homologous recombination and phage transduction for modifying chromosomal DNA. Specifically we use Escherichia coli as the host organism, and the overproduction of xylitol by reduction of xylose represents the biotransformation of interest.