Identification of pigmented extremophilic bacteria from mangrove soil with antibiofilm activity on food pathogens

Abstract

Mangrove ecosystems and associated microorganisms are always a source of curiosity for researchers. Pigment producing bacteria were isolated from the mangrove soil in Kadamakkudi, Cochin, Kerala. The bacteria were biochemically identified and by 16 S rRNA gene sequence. The pigments extracted had been tested for antibiofilm activity against food pathogens Pseudomonas aeruginosa (NCIM 2863), Klebsiella pneumoniae (NCIM 5215), and Escherichia coli (NCIM 2343). Antibiofilm activity was further confirmed by fluorescent and scanning electron microscopy. Six yellow-orange pigmented bacteria (KDR2, KDR3, KDR7, KDR8, KDR14 and KDS1) were isolated. KDR2 was identified as Cellulosimicrobium funkei, KDR7 and KDS1 as Cytobacillus depressus, KDR8 as Bacillus aquimaris, and KDR3 and KDR14 as Halobacillus sp. All of these organisms are known to be extremophiles. The UV-Visible absorption spectrum of all the pigments ranged from 400 nm to 550 nm with different absorbance maxima. All the pigments showed antibiofilm activity against the food pathogens tested.

Keywords

• Pigments
• Antibiofilm
• Extremophiles
• Live-dead staining
• Scanning electron microscopy