Research Article A Broad-Spectrum Antimicrobial Activity of Bacillus subtilis RLID 12.1 Ramya Ramachandran, 1 Ajay Ghosh Chalasani, 1 Ram Lal, 2 and Utpal Roy 1 1 Department of Biological Sciences, BITS Pilani KK Birla Goa Campus, Goa 403726, India 2 Department of Microbiology, SBSPGIBMS, Dehradun 248161, India Correspondence should be addressed to Utpal Roy; utpalroy010@gmail.com Received 15 January 2014; Accepted 27 June 2014; Published 11 August 2014 Academic Editor: Carla R. Arciola Copyright © 2014 Ramya Ramachandran et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. 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. Te antimicrobial potential of the wild- type isolate belonging to the genus Bacillus was determined by the cut-well agar assay. Te production of antimicrobial compound was recorded maximum at late exponential growth phase. Te ultrafltered concentrate was insensitive to organic solvents, metal salts, surfactants, and proteolytic and nonproteolytic enzymes. Te concentrate was highly heat stable and active over a wide range of pH values. Partial purifcation, zymogram analysis, and TLC were performed to determine the preliminary biochemical nature. Te 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. Te 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 insignifcant identity to other antimicrobial peptides from bacteria. Te minimum inhibitory concentrations of dialysed and partially purifed ion exchange fractions were determined against some selected gram-positive and gram-negative bacteria and some pathogenic yeasts. Te presence of three important antimicrobial peptide biosynthesis genes ituc, fend, and bmyb was determined by PCR. 1. Introduction Mechanism of resistance in clinical background refects very serious problem in the treatment of pathogenic microbes. Serious bacterial and fungal infections are increasingly recognized as important causes of morbidity and mortal- ity, especially among debilitated patients [1, 2]. Hospital- acquired infections are most commonly associated with invasive medical devices or surgical procedures which turn out to be a challenge to patient safety [2]. Famous hospital- acquired infections called “ESKAPE” (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter species, Pseudomonas aeruginosa, and Enterobacter species) are recognized as the most important emerging threats of this century [3]. To confront the growing antimicrobial resistances, mod- ern medicine focus natural products for novel antibiotics and antimicrobials. Strains of Bacillus subtilis, the model system for gram-positive organisms, are able to produce more than two dozen antibiotics with diferent structures and functions depending on the ecological niche or induced systematic resistance [4]. Bacillus isolates are rather well known for the production of a vast array of structurally unrelated antimicrobial compounds, which include lipopeptides like iturin, surfactin, fengycins, bacteriocins, and bacteriocin like inhibitory substances (BLIS) [5]. Te production of lipopeptides allows certain B. subtilis strains to modify their outer surface which permits them to regroup together in a bioflm in order to proliferate and spread in the territory. Te major types of antimicrobial compounds from B. subtilis include peptides that are either ribosomally synthesized and posttranslationally modifed (lantibiotics and lantibiotic-like peptides) or nonribosomally generated, as well as a couple of nonpeptidic compounds such as polyketides, an amino sugar, and a phospholipid [5]. Te multifarious antimicrobial compounds produced by various Bacillus strains have the Hindawi Publishing Corporation e Scientific World Journal Volume 2014, Article ID 968487, 10 pages http://dx.doi.org/10.1155/2014/968487