ABSTRACT
In the study, Bacillus megaterium T04 isolated from Rach Lang stream in Vietnam was identified. The stream samples were diluted in 0.9 % NaCl broth and then spread onto the ISP4 supplemented with rice and wheat starch. The colonies showed the strongest hydrolyzing activity were picked up and identified by biochemical test and 16S rRNA sequencing analysis. The starch hydrolyzing ability of this strain was detected by starch agar plate method. For maximum α-Amylase production, including 174.7 IU/ml and 0.2 IU/ml in medium containing wheat and rice, respectively was obtained after 72 h of incubation. The enzyme still showed high activity in 60% ammonium sulfate that was necessary for study on the enzyme characteristics. As a result, Bacillus megaterium T04 could produce high yield of amylase in simple conditions.
ABSTRACT
Bacillus megaterium T04 isolated from Rach Lang stream in Vietnam was tested for antimicrobial activities. The antimicrobial activities of Bacillus megaterium T04 (57.3x108 cfu/mL) against Candida albicans, Salmonella typhi, Pseudomonas aeruginosa, Staphylococcus sciuri, Micrococcus luteus were detected by agar well diffusion method in different cultivation conditions at three temperatures (25, 37, and 45oC) in three incubation periods (24, 48, and 72 hours). The efficacy of antimicrobial activities of this strain were determined in comparison with ceftriaxone activity against Candida albicans, Salmonella typhi, Pseudomonas aeruginosa, Staphylococcus scuiri, Micrococcus luteus. The antimicrobial activity potency was equivalent to ceftriaxone in a range ( 3.3 0.6 μg/mL to 46.5 6.2 μg/mL) for Candida albicans (0.9 0.2 μg/mL to 35.5 7.7 μg/mL) for Salmonella typhi, , (0.4 0.1 μg/mL to 28.4 4.4 μg/mL) for Pseudomonas aeruginosa, (119.8 21.2 μg/mL to 283.7 26.0 μg/mL) for Staphylococcus scuiri, (3.3 0.4 μg/mL to 64.4 7.4 μg/mL) for Micrococcus luteus.