Lactic acid bacteria were screened for potential probiotics for use as feed additives. We obtained 3,000 isolates from feces of: cattle, dogs, goats, and infants; milk; yogurt; cheese; fermented sausages; Kimchi; and Cheonggukjang and tested their antibacterial activity toward indicator pathogens, including Bacillus cereus, Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella enterica Enteritidis. We further tested their tolerance to artificial gastric juice (1% [w/v] pepsin, pH 2.5) and bile acid (0.1% [w/v] oxgall, pH 6.8). Six isolates exhibited strong antibacterial activity against indicator pathogens. The PA40 isolate from Kimchi exhibited marked resistance to artificial gastric juice and bile acid. The antibacterial substances produced by PA40 were stable to heat, pH, and enzymes. Strain PA40 was identified as a Lactobacillus curvatus strain using chemical tests and 16S rDNA sequencing and produced 248.4 mmol/L lactic acid after 48 hr of fermentative growth. The L. curvatus PA40 strain was also highly tolerant of the artificial gastrointestinal model system. Our results indicate that L. curvatus PA40 could be used as a potential probiotic feed additive.
Bacillus eiseniae sp. nov., a swarming, moderately halotolerant bacterium isolated from the intestinal tract of an earthworm (Eisenia fetida L.) values between the isolate and the reference strains were ¡38.3 %. The DNA G+C content of strain A1-2 T was 38.5 mol%. The predominant menaquinone was MK-7 and the major polar lipids were diphosphatidylglycerol and phosphatidylethanolamine. The major cellular fatty acids were iso-C 15 : 0 (51.5 %) and anteiso-C 15 : 0 (29.6 %) and the cell-wall diamino acid was mesodiaminopimelic acid. On the basis of 16S rRNA gene sequence analysis and chemotaxonomic and phenotypic characteristics, it is concluded that strain A1-2 T represents a novel species of the genus Bacillus, for which we propose the name Bacillus eiseniae sp. nov. The type strain is A1-2
A Gram-stain-positive, aerobic, endospore-forming, moderately halophilic rod, designated strain R1T, was isolated from rice husks and subjected to a taxonomic study using a polyphasic approach. Strain R1T produced spherical or ellipsoidal endospores at a subterminal position in swollen sporangia, and was catalase- and oxidase-positive. The isolate grew optimally at 37 °C and pH 6.0–7.0, and could grow in the presence of up to 9 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain R1T belongs to the genus
Bacillus
. The closest relatives of strain R1T were
Bacillus subtilis subsp. subtilis
NCIB 3610T,
Bacillus aquimaris
TF-12T, and
Bacillus marisflavi
TF-11T, with 16S rRNA gene sequence similarities of 96.0 %, 98.4 %, and 98.7 %, respectively. DNA–DNA relatedness values between the isolate and the reference strains were ≤42±3 %. The predominant menaquinones were MK-5 (50 %) and MK-7 (50 %). The major polar lipids were phosphatidylglycerol, diphosphatidylglycerol, and phosphatidylethanolamine. The major cellular fatty acids were iso-C15 : 0 (48.6 %) and anteiso-C15 : 0 (20.6 %), and the cell-wall diamino acid was meso-diaminopimelic acid. On the basis of 16S rRNA gene sequence analyses and chemotaxonomic and phenotypic characteristics, it is concluded that strain R1T represents a novel species of the genus
Bacillus
, for which we propose the name Bacillus oryzaecorticis sp. nov. The type strain is R1T ( = KACC 17217T = KCCM 90231T = JCM 19602T).
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