title: Evaluation of microbial strains for linoleic acid hydroxylation and reclassification of strain ALA2.
abstract: In previous studies, a new microbial strain ALA2 was isolated which produced many new products from linoleic acid [Gardner H.W., Hou C.T., Weisleder D. and Brown W. 2000. Lipids 35: 1055-1060; Hou C.T. 1998. 12,13,17-Trihydroxy-9(Z)-Octodecenoic acid and derivatives and microbial isolate for production of the acid. US Patent No. 5, 852, 196]. Strain ALA2 was preliminary 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 20 type strains from the phylogenetically related genus Microbacterium were studied. Surprisingly, all of these strains tested showed very little or no activity in converting linoleic acid. On 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 B. megaterium type strain. Therefore, strain ALA2 is now reclassified as B. megaterium. Screening of 56 strains of B megaterium strains showed that many of them were able to produce reasonable amounts of hydroxyl fatty acids from linoleic acid, although strain ALA2 possessed the greatest activity.
authors.affiliation: Microbial Genomics and Bioprocessing Research Unit, National Center for Agricultural Utilization Research, Agricultural Research Service, US Department of Agriculture, 1815 North University Street, Peoria, IL 61604, USA. houct@ncaur.usda.gov
authors.forename: Ching T
authors.initials: CT
authors.lastname: Hou
authors.forename: David P
authors.initials: DP
authors.lastname: Labeda
authors.forename: Alejandro
authors.initials: A
authors.lastname: Rooney
mesh_terms: D000192:Actinomycetales / Q000145:classification* / Q000235:genetics / Q000378:metabolism; D001410:Bacillus megaterium / Q000145:classification* / Q000235:genetics / Q000378:metabolism; D004269:DNA, Bacterial / Q000032:analysis; D004275:DNA, Ribosomal / Q000032:analysis; D005227:Fatty Acids / Q000378:metabolism; D020459:Genes, rRNA; D006900:Hydroxylation; D019787:Linoleic Acid / Q000378:metabolism*; D008969:Molecular Sequence Data; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D005227:Fatty Acids; D012336:RNA, Ribosomal, 16S; D019787:Linoleic Acid