Organic Solvent Tolerance of Halophilic Archaea

Organic solvent tolerance was tested in type strains of type species of the sixteen genera of Halobacteriaceae, the halophilic archaea. Most of the strains were observed to grow in the presence of hexylether (log P ow =5.1), but none grew in the presence of n-octane (log P ow =4.9) except Halogeometricum borinquense JCM 10706 T and Halorubrum saccharovorum JCM 8865 T . On the other hand, two strains, Haloarcula spp. OHF-1 and 2 isolated from a French solar salt were found to show stronger tolerance even to isooctane (log P ow =4.8). Growth of some strains was retarded by the presence of n-decane but reached to the same cell densities at late stationary phase. Final cell densities of some strains were greatly repressed by the presence of the solvent.