The aerobic bacterial metabolism of phytol in seawater: Temperature dependence of an abiotic intermediate step and its consequences

Abstract A non-negligible production of 6,10,14-trimethylpentadecan-2-one has been often observed during aerobic phytol incubations with bacteria. In this work involving a marine Acinetobacter , a combination of biotic and abiotic processes is proposed in order to explain this phenomenon. In seawater, phytenal produced by bacterial oxidation of phytol can be converted abiotically to this isoprenoid ketone after addition of a water molecule and subsequent retro-aldol reaction. This abiotic process is very sensitive to temperature. It was demonstrated in this study that at 30°C an important part of phytol is metabolized through 6,10,14-trimethylpentadecan-2-one, whereas this pathway practically disappeares at 13°C. Consequently, in studies concerning phytol biodegradation, it will be important to take into account the effect of temperature.