Isolation and Identification of Bacillus Strains from Yak Intestine
In order to isolate and identify the bacterial resources of beneficial bacteria in the intestines of yaks,the intes-tinal contents of Tibetan yak were collected,from which the dominant bacteria were isolated and purified.The species were identified through 16S rDNA sequence comparison and biochemical tests.Their morphology was observed through Gram staining.The bacterial characteristics were identified through physiological and biochemical tests such as stress resistance,adhesion ability,hemolytic activity,antibacterial ability in vitro,and drug sensitivity testing.Sensi-tivity and other physiological and biochemical tests were conducted to identify the characteristics of the strains.Four bacterial strains were successfully isolated and purified from yak feces and identified as Bacillus subtilis(XZMN-1),Bacillus pumilus(XZMN-2),Bacillus veleis(XZMN-3)and Bacillus cereus(XZMN-4).The four isolated strains were all γ-hemolytic,had no biofilm,had highly resistant to bile salts and acid,and could survive in a medium with pH 3.0.XZMN-3 and XZMN-4 were resistant to high temperatures,and their activity could still be detected when the bac-terial solution was incubated at 80℃for 30 minutes.The four strains of bacteria were sensitive to most antibiotics.Their hydrophobicity in different solvents varies greatly(1.91%-93.15%),and their self-agglutination properties range from 13.29%to 60.63%.All four strains of bacteria had inhibitory effects on Salmonella,and XZMN-1 and XZMN-2 had inhibitory effects on Staphylococcus aureus.In summary,the four strains of Bacillus isolated and purified had high stress resistance and strong adhesion performance.Among them,XZMN-1 was sensitive to most antibiotics and could be used as a candidate strain for developing highly active probiotic feed additives.
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维普
