Activity-guided separation and characterization of new halocin HA3 from fermented broth of Haloferax larsenii HA3

• Published in: Extremophiles : life under extreme conditions Vol. 21; no. 3; pp. 609 - 621
• Main Authors: Kumar, Vijay, Tiwari, Santosh Kumar
• Format: Journal Article
• Language: English
• Published: Tokyo Springer Japan 01.05.2017; Springer Nature B.V
• Subjects: Acids; Aerobic conditions; Antimicrobial agents; Archaeal Proteins - chemistry; Archaeal Proteins - metabolism; Bacteriocins - chemistry; Bacteriocins - genetics; Bacteriocins - metabolism; Biochemistry; Biomedical and Life Sciences; Biotechnology; Chromatography; Detergents; Fermentation; Haloferax; Haloferax - metabolism; Life Sciences; Microbial Ecology; Microbiology; Microorganisms; Morphology; Organic solvents; Original Paper; Protein Stability; Proteolysis; Salt; Sodium chloride; Space life sciences; Ultrafiltration; Yeast; Mumbai India; India; Halocin; Cytocidal; Cell viability; Salted foods; HA3; Cell morphology; Haloferax larsenii HA3
• ISSN: 1431-0651; 1433-4909
• DOI: 10.1007/s00792-017-0930-6

Haloferax larsenii HA3 was able to grow optimally in HS medium containing 15% NaCl, at pH 7.2 and 42 °C in aerobic conditions. Strain HA3 was found to be round shape, Gram-negative, catalase-positive, sensitive to bile acid, and resistant to chloramphenicol, and could not utilize arginine. The lipid profile revealed the presence of glycerol diether moiety (GDEM) suggesting Haloarchaea characteristics. Phylogenetic analysis based on 16S rRNA gene sequence similarities showed that it was closely related to H. larsenii ZJ206. Interestingly, strain HA3 was found to produce halocin HA3 which was purified using ultrafiltration and chromatography. It was found to be stable up to 80 °C, pH 2.0–10.0, organic solvents, surfactants, and detergents tested. However, the activity of halocin HA3 was completely reduced in the presence of proteinase K and trypsin. It was found to be halocidal against H. larsenii HA10, rupturing cell boundary and leading to cell death. The molecular weight of halocin HA3 was found to be ~13 kDa and MALDI-TOF MS/MS analysis suggested no homology with known halocins. The N-terminal ten amino-acid residues, NH 2 MNLGIILETN—COOH, suggested a new/novel halocin. These properties of halocin HA3 may be applicable for control of Haloarchaea in environments and salted foods.