Submitted to: Antonie Van Leeuwenhoek
Publication Type: Peer reviewed journal
Publication Acceptance Date: 3/8/2005
Publication Date: 6/1/2005
Citation: Hou, C.T., Labeda, D.P., Rooney, A.P. 2005. Evaluation of microbial strains for linoleic acid hydroxylation and reclassification of strain ALA2. Antonie van Leeuwenhoek. 88:167-171. Interpretive Summary: Previously, we discovered a new microbial strain, ALA2, that produced seven new polyhydroxy unsaturated fatty acids from linoleic acid. Hydroxy fatty acids are useful as starting materials for the synthesis of specialty chemicals, special military nylon, plastisizers, coatings and physiologically active agents. To determine if strain ALA2 is the optimal strain for industrial applications of hydroxyl fatty acids, other related strains were screened. Strain ALA2 was re-classified as Bacillus megaterium by DNA analysis. Screening of many strains of Bacillus showed that many of them were able to produce hyroxyl fatty acids from linoleic acid; however, strain ALA2 possesses the greatest activity. Strain ALA2 is selected for further studies for the production of industrial products. Application of these new products either for bioactive agents or raw material for synthesis of specialty chemicals will benefit U.S. farmers.
Technical Abstract: In previous studies, a new microbial strain ALA2 was isolated which produced many new products from linoleic acid. Strain ALA2 was identified as Clavibacter sp. based on its physiological and fatty acid profiles. To determine if strain ALA2 is the optimal strain for industrial applications, other related strains were screened for their abilities to convert linoleic acids. Two strains from Clavibacter and twenty strains from its phylogenetically related genus Microbacterium were screened. Surprisingly, all of these strains tested showed very little or no activity in converting linoleic acid. During reexamination of the identification of strain ALA2, the sequence of the 16S ribosomal RNA gene of ALA2 was found to be 99% identical to that of Bacillus megaterium and the strain was also found to have 76.3% DNA homology to the type strain. Therefore, strain ALA2 is now reclassified as Bacillus megaterium. Screening of 27 strains of Bacillus megaterium strains showed that many of them were able to produce hydroxyl fatty acids from linoleic acid, however, strain ALA2 possesses the greatest activity.