Isolation and identification of lactic acid bacteria from sediments of a coastal marsh using a differential selective medium.
OBJECTIVE
To identify lactic acid bacteria (LAB) colonies isolated from sediments of a coastal marsh by the reduction of 2,3,5-triphenyltetrazolium chloride (TTC) in MRS medium.


RESULTS
Single colonies isolated from sediments of a coastal marsh by enrichment in MRS broth were selected from MRS-TTC plates and classified according to colony phenotype based on TTC reduction. A total of 37 colonies grouped in seven different phenotypes were identified by analysis of its 16S ribosomal gene sequence. Most isolates belonged to the Firmicutes phylum, mainly to orders Bacillales and Lactobacillales. LAB were represented by 20 isolates, 15 of which belong to the genus Weissella.


CONCLUSIONS
Enrichment in MRS was highly selective for the isolation of bacteria belonging to phylum Firmicutes. Several different phenotypes were developed by LAB and must be considered during LAB isolation based on TTC reduction.


CONCLUSIONS
To our knowledge, this is the first study aimed at determining a relationship between colony phenotype from TTC reduction and a partial identification of isolates based on 16S ribosomal gene sequence similarities. Besides, this is the first report of isolation of W. cibaria from environmental samples.
Zamudio-Maya
M
M
Facultad de Ingeniería Química, Universidad Autónoma de Yucatán, Mérida, Yucatán, Mexico.
Narváez-Zapata
J
J
Rojas-Herrera
R
R
D001431:Bacteriological Techniques; D003470:Culture Media; D004269:DNA, Bacterial / Q000032:analysis; D004755:Enterobacteriaceae / Q000145:classification / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification; D019015:Geologic Sediments / Q000382:microbiology*; D006094:Gram-Positive Bacteria / Q000145:classification / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification; D019344:Lactic Acid / Q000096:biosynthesis*; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D010641:Phenotype; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D013778:Tetrazolium Salts / Q000378:metabolism*; D053833:Wetlands
D003470:Culture Media; D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S; D013778:Tetrazolium Salts; D019344:Lactic Acid; C009591:triphenyltetrazolium