| dc.description.abstract | Biological activities of Geobacillus stearothermophilus N014 isolated from Rach Lang stream in Vietnam was screened in this study. The activities tested included antimicrobial activity and starch hydrolysis ability. The antimicrobial activities of Geobacillus stearothermophilus N014 against five common human pathogens (Candida albicans, Salmonella typhi, Pseudomonas aeruginosa, Staphylococcus sciuri, Micrococcus luteus) were detected by agar well diffusion method in 27 cultivation conditions of three media (LB, ISP media number 4 supplemented with rice starch, and ISP medium number 4 supplemented with wheat starch) at three temperatures (25, 37, and 45oC) in three incubation periods (24, 48, and 72 hours). The potency and efficacy of antimicrobial activity of this strain were determined in comparison to ceftriaxone activity against the pathogens. The antimicrobial activity potency against Candida albicans (3.1 0.5 to 58.2 9.3 μg/mL), Salmonella typhi (0.9 0.2 to 35.5 7.7 μg/mL), Pseudomonas aeruginosa (0.4 0.1 to 28.4 4.4 μg/mL), Staphylococcus scuiri (62.4 11.1 to 3721.3 954.5 μg/mL), Micrococcus luteus (3.3 0.4 to 64.4 7.4 μg/mL) was determined. The starch hydrolysis ability of this strain was detected by starch agar plate method. The activities of these enzymes were compared to standard α-amylase. The potential to produce thermostable enzymes at 45oC were also revealed. Ammonium sulfate fractionation was done to concentrate the starch hydrolysis enzyme at 60% saturation. That was necessary for study on the enzyme characteristics.
Key words:
Antimicrobial activity
Geobacillus stearothermophilus N014
Starch hydrolysis ability | en_US |
