A Broad-Spectrum Antimicrobial Activity ofBacillus subtilisRLID 12.1

Abstract

In the present study, an attempt was made to biochemically characterize the antimicrobial substance from the soil isolate designated as RLID 12.1 and explore its potential applications in biocontrol of drug-resistant pathogens. The antimicrobial potential of the wild-type isolate belonging to the genus Bacillus was determined by the cut-well agar assay. The production of antimicrobial compound was recorded maximum at late exponential growth phase. The ultrafiltered concentrate was insensitive to organic solvents, metal salts, surfactants, and proteolytic and nonproteolytic enzymes. The concentrate was highly heat stable and active over a wide range of pH values. Partial purification, zymogram analysis, and TLC were performed to determine the preliminary biochemical nature. The molecular weight of the antimicrobial peptide was determined to be less than 2.5 kDa in 15% SDS-PAGE and in zymogram analysis against Streptococcus pyogenes. The N-terminal amino acid sequence by Edman degradation was partially determined to be T-P-P-Q-S-X-L-X-X-G, which shows very insignificant identity to other antimicrobial peptides from bacteria. The minimum inhibitory concentrations of dialysed and partially purified ion exchange fractions were determined against some selected gram-positive and gram-negative bacteria and some pathogenic yeasts. The presence of three important antimicrobial peptide biosynthesis genes ituc, fend, and bmyb was determined by PCR.

Antibacterial Activity, Cytotoxicity, and the Mechanism of Action of Bacteriocin from <b><i>Bacillus subtilis</i></b> GAS101

“…Shelburne et al [23] reported that subtilosin A (3,399.7 Da) from B. subtilis displayed an MIC of > 200 mg/L against S. epidermidis ATCC 12228 and > 100 mg/L against E. coli. In another study, partially purified bacteriocin from soil isolate B. subtilis RLID 12.1 inhibited the growth of S. epi dermidis at > 200 µg/mL and did not exhibit any activity against E. coli [24]. The bacteriocin in our study displayed antimicrobial activity against a broad spectrum of grampositive and gram-negative bacteria.…”

Bioremediation of heavy metals from aquatic environment through microbial processes: A potential role for probiotics?

“…It has been also reported that Bacillus subtilis [28] and E. faecium [29] inhibited the growth of E. coli. Furthermore, the ultrafiltered concentrate of the cell-free culture of B. subtilis showed inhibitory effects against E. coli [30]. In both protocols, the culture broth was taken to test antibacterial activity.…”

“…The isolate was grown in MRS broth (HiMedia, M369), without heavy metals at 37°C for 24 h. After incubation, the optical density of the broth culture was adjusted to OD600 = 0.1 using a light spectrophotometer (JENWAY, 7305). A loopful of the broth culture was then aseptically streaked onto MRS agar (HiMedia, M641) supplemented with different heavy metals (Hg, Cr, Cd, and Pb), respectively, at different concentration (10,20,30,40, and 50 ppm). The plates were then incubated at 37°C for 48 h. Single colonies or trace of growth was ignored.…”

Production of antimicrobial agents by Bacillus spp. isolated from Al-Khor coast soils, Qatar

“…In the present investigation, the antibacterial activity of 25 Bacillus isolates against wide range of Gram-positive and Gram-negative bacteria were demonstrated. These isolates were identified based on their morphological, physical, and biochemical characteristics using Bergey"s manual and other scientific literature (Arbsuwan et al, 2014;Arumugam et al, 2017;Ramachandran et al, 2014;Malanicheva et al, 2012). It has been also observed that highest antibacterial activity was demonstrated against S. aureus and S. epidermis than E. coli.…”

“…subtilis, B. lichenoformis, B. coagulans, B. us megaterium, B. polymyxa, and Brevibacillus brevis. (Arbsuwan et al, 2014;Arumugam et al, 2017;Jianmei et al, 2015;Ramachandran et al, 2014;Malanicheva et al, 2012;Sumi et al, 2015).…”