Solvent selection for the biotransformation of terpenes by Pseudomonas putida

A two-phase reaction system for the biotransformation of terpenes was implemented in order to protect the microorganism from the toxic effects of substrates, intermediates and products and to prevent the oxidation of the compounds by oxygen and/or water. Preliminary studies were carried out with a Pseudomonas putida wild strain. Growth of the wild strain was not affected by the presence of 0.5% (v/v) alpha-pinene. However, the presence of alpha-pinene oxide in concentrations above 0.2% (v/v) had a progressive inhibitory effect on growth (complete inhibition occurred at 0.5%). Since substrate and/or product toxicity can often be overcome by the use of an organic solvent reservoir, we searched for a biocompatible solvent. Solvents with a log P close to 4.5 were the most effective in minimising alpha-pinene oxide toxicity, especially 1-dodecanol, as judged from growth and oxygen uptake experiments. Although the growth rate was 25% lower in the presence of 2% (v/total volume) of organic phase, growth and oxygen consumption rates were not further affected by the introduction of 0.5% (v/total volume) of alpha-pinene oxide in the solvent phase. The substrate alpha-pinene itself(log P 4.9) was tested as a solvent reservoir for alpha-pinene oxide and found effective. (C) 1998 Elsevier Science B.V. All rights reserved.