Full text loading...
Abstract
A new, modified culture method that utilizes a transwell plate with a 0.4 µm pore-size microporous membrane was developed. This system allows only trace nutrients from the soil into the liquid culture through the microporous membrane. The method is a more powerful tool for the discovery of novel species from soils than are traditional methods. Such newly identified species could potentially produce useful metabolites. A bacterial strain, T515T, was isolated using this modified culture method. Growth of strain T515T occurred at pH 4–9 in a temperature range between 20 °C and 40 °C and in the presence of 0–2 % (w/v) NaCl on R2A agar. Colonies on the agar plates were tiny, white, and convex after 5 days incubation at 28 °C. Comparative analysis of the nearly full-length 16S rRNA gene sequence of strain T515T revealed close pairwise similarity with species of the genus Bacillus , and strain T515T was most closely related to Bacillus panaciterrae Gsoil 1517T (96.7 %) and Bacillus funiculus NAF001T (96.0 %). The major quinone of strain T515T was menaquinone-7 (MK-7) and the major fatty acids were iso-C15 : 0 (45.5 %), anteiso-C15 : 0 (23.2 %) and C16 : 0 (10.9 %). The predominant polar lipids were diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. Strain T515T was sensitive to streptomycin and tetracycline, but resistant to rifampicin (0.125 µg ml−1), ampicillin (0.5 µg ml−1) and chloramphenicol (1 µg ml−1). The strain showed antimicrobial activities against the six strains tested: Bacillus subtilis KEMB 51201-001, Staphylococcus aureus KEMB 4659, Pseudomonas aeruginosa KACC 10185, Staphylococcus epidermidis KACC 13234, Paenibacillus larvae KACC 14031 and Escherichia coli KEMB 212-234. Based on these results, strain T515T represents a novel species of the genus Bacillus with the proposed name, Bacillus polymachus sp. nov. The type strain is T515T ( = KEMB 9005-168T = KACC 18242T = NBRC 110614T).
- Published Online:
Funding
- Kyonggi University Research Grant