PRODUCTION OF PRIMARY ALIPHATIC-ALCOHOLS WITH A RECOMBINANT PSEUDOMONAS STRAIN, ENCODING THE ALKANE HYDROXYLASE ENZYME-SYSTEM

In this paper we describe the biosynthesis of a series of 1-alkanols from the corresponding n-alkanes. To this end, we introduced the alkane hydroxylation system of Pseudomonas oleovorans into Pseudomonas putida PpS81 (alcA81). The resulting recombinant strain PpS8141 can oxidize n-alkanes to the corresponding 1-alkanols but is unable to utilize the alkanols, which therefore accumulate in the medium. PpS8141 was grown in two-liquid-phase bioreactors. The different medium-chain-length alkanes formed a bulk organic phase, which constituted 20% of the total volume. The aqueous phase contained the growth substrate citrate, octanoate, or pyruvate. PpS8141 was able to grow well in the presence of a bulk apolar phase only when pyruvate was used as the growth substrate. Hexane was toxic to this strain and did not allow growth. The strain oxidized C7-C-11 linear alkanes to 1-alkanols with production rates superior to the wild-type P. oleovorans rates. With n-octane and n-nonane as organic phase and substrate, we found the highest production rates of 1-alkanol. The growth rate in the exponential phase and the maximal 1-alkanol production rate showed an inverse relationship, which we interpret to be the result of the metabolic burden of the conversion. The results show that the recombinant strain PpS8141 may allow the biotechnological production of primary aliphatic alcohols