Bile salt hydrolase activity and cholesterol assimilation of lactic acid bacteria isolated from flowers

A total of 16 isolates of lactic acid bacteria (LAB) from flowers were screened for the bile salt hydrolase activity on MRS(de Man, Rogosa and Sharpe; Difco) agar supplemented with 0.5% (w/v) taurodeoxycholic acid. The isolates were dividedinto two groups based on their phenotypic characteristics and 16S rRNA gene sequence analysis of the representativeisolates. Group I isolates were cocci as the members of genus Enterococcus. Isolates FM1-1, FM1-2, FM12-1, andFM12-2 were identified as Enterococcus durans (100% similarity), isolate FM2-3 was identified as Enterococcusgallinarum (99.92% similarity), while the isolate FM11-2 was identified as Enterococcus lactis (99.77% similarity).Group II isolates were rods as the members of genus Lactobacillus. They were identified as Lactobacillus plantarumsubsp. plantarum (the representative isolates, FM3-1 and FM16-2, showed 100% similarity). Eleven isolates, includingFM1-1, FM1-2, FM2-3, FM3-1, FM4-2, FM11-2, FM12-1, FM12-2, FM14-1, FM14-2, and FM16-2, exhibited bilesalt hydrolase activity. All LAB isolates showed the cholesterol assimilated ability ranged from 9.57% to 51.69%. Theisolate FM11-2 efficiently assimilated the cholesterol with 51.69%.

Characterization of cellulase producing Bacillus and Paenibacillus strains from Thai soils.

Seventeen strains of cellulase producing bacteria were isolated from soil samples collected in Nan province, Thailand. They exhibited cellulase activity as a clear zone surrounded their colonies grown on carboxymethyl cellulose (CMC) agar medium ranged from 0.63 to 2.95 cm in diameter. Their hydrolysis capacity values were 1.65 - 7.55. The bacteria isolated were divided into 2 groups and belonged to genus Bacillus and Paenibacillus based on their phenotypic characteristics and chemotaxonomic characteristics such as meso-diaminopimelic in cell wall peptidoglycan and menaquinones of MK-7. Bacillus strains, P3-1 and P4-6 in Group I, produced maximum cellulase at 0.015 U ml-1. Their optimal pH and temperature for enzyme production and enzyme activity were 7.0 and 50 oC, respectively. The strains P3-1 and P4-6 were closely related to Bacillus velesensis LMG 22478T (100% similarity) whereas representative strain, S10-4 in Group II, was closely related to P. cellulositrophicus KCTC 13135T (98.7% similarity) based on 16S rRNA gene sequence. On the basis of their phenotypic, chemotaxonomic characteristics and phylogenetic analysis of 16S rRNA gene sequence, the strains P3-1 and P4-6 were identified as B. velesensis and the strain S10-4 was a novel species in the genus Paenibacillus.

Screening and characterization of protease-producing Virgibacillus, Halobacillus and Oceanobacillus strains from Thai fermented fish.

Halophilic bacteria from fermented fish (pla-ra and pla-chom), shrimp paste (ka-pi) and fermented crab] were isolated and screened for protease activities. Twenty-seven isolates exhibited protease specific activities ranged from 0.12 to 3.62 unit/mg protein. Isolate TPPN2-1 from pla-ra produced maximal protease specific activity (3.62 units/mg protein). They were Gram-positive, moderately halophilic rod-shaped bacteria and were divided into 5 groups on the basis of their phenotypic and chemotaxonomic characteristics, DNA-DNA relatedness including the 16S rRNA gene sequences analyses. Three isolates (Group I) were identified as Virgibacillus halodenitrificans, 3 isolates (Group II) as V. marismortui, 7 isolates (Group III) as V. dokdonensis, 10 isolates (Group IVA & IVB) as Halobacillus species and 4 isolates (Group V) as Oceanobacillus iheyensis.