Identification And Characterization Of Pigmented Bacteria Isolated From Malaysian Seawater

Purpose of study: Bacteria can naturally produce pigments that can be useful for various applications as they possess antimicrobial metabolites among other numerous benefits towards the human health. This study was carried out to identify the species of marine bacterial isolates PMA, PM3C1 and PM5C1 exhibiting yellow, orange and green colors respectively. Methodology: The current study is using Polymerase Chain Reaction (PCR) amplification and sequence analysis of their 16S rRNA gene. The stability of pigments extracted from the bacterial samples was also analyzed against different temperature and light conditions. Main Findings: Sequence alignment using BLAST revealed that the yellow, orange, and green-pigmented bacteria have 84% similarity with Staphylococcus aureus, 85% similarity with Exiguobacterium profundum and 95% similarity with Pseudomonas aeruginosa respectively. The green pigment showed major changes in color following exposure to sunlight and fluorescent light, and when incubated at 24°C and 50°C. Exposure to direct sunlight also results in the reduction of color for the yellow and orange extracts, while no effect was observed for both pigments under fluorescent light. Incubation at 50°C results in the reduction of the orange color, while the yellow pigment was observed to be unaffected suggesting its stability at high temperature. Implications: Natural pigments production can provide many advantages including reduction of pollution generation, ease of disposal and other benefits to the human health.