Whole cell biocatalysts stabilization for l-carnitine production

We present how whole cells can be used in different ways to stabilize enzyme catalysts in the cell environment to perform biotransformations. Some of the factors which affect their use in biotransformations, such as the nature of the substrate/product, the reusability of cells, the extension of cell viability by cell activation periods or the addition of energetic substrates and the stabilization in solids supports, are considered. The use of sufficiently active enzymes in the cell environment to perform biotransformations within growing, resting, permeabilized, dried, osmotically stressed, freely suspended and immobilized cells, is discussed in the text. The different cell states of enterobacteria, such as Escherichia coli and Proteus sp., can be used to produce l-carnitine from crotonobetaine or d-carnitine substrate, are analyzed.