Vibrio furnissii M1 was recently reported to biosynthesize n-alkanes when grown on biopolymers, sugars, or organic acids (M. O. Park, J. Bacteriol. 187:1426-1429, 2005). In the present study, V. furnissii M1 was subjected to genomic analysis and studied biochemically. The sequence of the 16S rRNA gene and repetitive PCR showed that V. furnissii M1 was not identical to other V. furnissii strains tested, but the level of relatedness was consistent with its assignment as a V. furnissii strain. Pulsed-field gel electrophoresis showed chromosomal bands at approximately 3.2 and 1.8 Mb, similar to other Vibrio strains. Complete genomic DNA from V. furnissii M1 was sequenced with 21-fold coverage. Alkane biosynthetic and degradation genes could not be identified. Moreover, V. furnissii M1 did not produce demonstrable levels of n-alkanes in vivo or in vitro. In vivo experiments were conducted by growing V. furnissii M1 under different conditions, extracting with solvent, and analyzing extracts by gas chromatography-mass spectrometry. A highly sensitive assay was used for in vitro experiments with cell extracts and [(14)C]hexadecanol. The data are consistent with the present strain being a V. furnissii with properties similar to those previously described but lacking the alkane-producing phenotype. V. furnissii ATCC 35016, also reported to biosynthesize alkanes, was found in the present study not to produce alkanes.