Here we present current results of a whole-cell bio catalytic conversion of aliphatic organic acids into di-acids with a recombinant E. coli strain expressing a monooxygenase from Pseudomonas putida.

It has been shown that alkanes are readily oxidised to carboxylic acids by recombinant E. coli expressing a monooxygenase from P. putida¹. However, the produced acids are generally toxic for the biocatalyst, limiting the product accumulation significantly. There are hints in the literature that P. putida is able to further convert the monocarboxylic acids into less toxic di-acids under certain circumstances².

We determined the ability of recombinant E. coli to oxidise toxic aliphatic organic acids to less toxic di-acids, allowing for example the production of adipic acid from hexanoic acid.

The conditions for the conversion are optimised, giving special emphasis to the regulation of the recombinant operon.

References:

[1] Rothen, S.A., Sauer, M., Sonnleitner, B., Witholt, B. (1998) Biotransformation of octane by E. coli HB101[pGEc47] on defined medium: octanoate production and product inhibition. Biotechnol. Bioeng. 58, 356-65.

[2] Kunz, D.A., Weimer, D.J. (1983) Bacterial formation and metabolism of 6-hydroxyhexanoate: evidence of a potential role for omega-oxidation. J. Bacteriol. 156, 567-75