AUTOMATED SYSTEMS FOR IDENTIFICATION OF HETEROTROPHIC MARINE-BACTERIAON THE BASIS OF THEIR FATTY-ACID COMPOSITION

The fatty acid methyl ester composition of a total of 71 marine strain s representing the genera Alteromonas, Deleya, Oceanospirillum, and Vi brio was determined by gas-liquid chromatographic analysis. Over 70 di fferent fatty acids were found. The predominant fatty acids were 16:0, 16:1 cis 9, summed-in-feature (SIF) 4 (15:0 iso 2OH and/or 16:1 trans 9) and SIF 7 (18:1 cis 11, 18:1 trans 9, and/or 18:1 trans 6) for all the strains considered, but minor quantitative variations could be us ed to distinguish the different genera, In addition to a conventional statistical processing method to analyze the data and draw comparison between species and genera, an approach involving neutral network-base d elaboration is applied. The statistical analysis and dendrogram repr esentation gave a comparison of the species considered, while the neur al network computation provided a more accurate assignment of species to their genera. Moreover, by using neural networks, it was possible t o conclude that only 22 fatty acids were ere important for the identif ication of the marine genera considered. A database of Alteromonas, De leya, Oceanospirillum, and Vibrio fatty acid methyl ester profiles was generated and is now routinely used to identify fresh marine isolates .