A whole cell biocatalyst for double oxidation of cyclooctane.

A novel whole cell cascade for double oxidation of cyclooctane to cyclooctanone was developed. The one-pot oxidation cascade requires only a minimum of reaction components: resting E. coli cells in aqueous buffered medium (=catalyst), the target substrate and oxygen as environmental friendly oxidant. Conversion of cyclooctane was catalysed with high efficiency (50% yield) and excellent selectivity (>94%) to cyclooctanone. The reported oxidation cascade represents a novel whole cell system for double oxidation of non-activated alkanes including an integrated cofactor regeneration. Notably, two alcohol dehydrogenases from Lactobacillus brevis and from Rhodococcus erythropolis with opposite cofactor selectivities and one monooxygenase P450 BM3 were produced in a coexpression system in one single host. The system represents the most efficient route with a TTN of up to 24363 being a promising process in terms of sustainability as well.