Antimicrobial Activity and Bioactive Compound Producing Halophilic Bacteria

Halophilic bacteria are commonly found in natural environments containing significant concentration of
NaCl that harbor a number of microbes producing novel bioactive compounds. In this study we aimed
to isolate and screen out the halophilic bacteria and to determine their activity for production of the
bioactive compounds. Marine soil sediments were collected from the solar saltpans of Thoothukudi
District, Tamil Nadu, India. Based on colony morphology, two species were isolated and identification
was done by using morphological and biochemical tests. The extracts of cell-free supernatant of the
two halophilic isolates were screened for bioactive compound and tested for antimicrobial activity
against human pathogenic bacteria such as Staphylococcus aureus, Pseudomonas sp, Klebsiella sp,
Vibrio sp, Escherichia coli and fungi Aspergillus niger and Penicillium chrysogenum by the agar cup
diffusion method. The results were then compared to standard antibiotics which showed 80% of
similar activity in 50 μL/g concentration. In addition, the arbitrary unit of two isolates was calculated
against S. aureus which produced enhanced inhibitory results. These findings show that the saline
soil of Thoothukudi represents an untapped source of bacterial biodiversity and also that most
bacterial isolates are capable of antibacterial and antifungal metabolite production.