Phenotypic characterization of pink pigmented facultative methylotrophic bacteria from soil exposed to vehicular soot

• Main Authors: Jang, Seung Bong, Lee, Anthony C.
• Format: text
• Published: Animo Repository 2008
• Subjects: Methylotrophic bacteria; Biology
• Online Access: https://animorepository.dlsu.edu.ph/faculty_research/7775
• Institution: De La Salle University

Twenty three (23) pink pigmented facultative methylotrophic bacterial isolates were obtained from soil collected along the island pavement of Taft Avenue fronting De La Salle University-Manila campus. They were described in terms of morphological and biochemical properties, as well as, responses to selected antimicrobials. All isolates were gram-negative rod shaped cells with sudanophilic cysts. Colonial morphologies of the isolates were described after growing them in both minimal and enriched media. All bacterial isolates showed circular, entire, opaque, raised to convex colonies regardless of the media used. Differences however, in terms of intensity of pink pigmentation and consistency were observed when the isolates were grown in different media. In terms of biochemical characteristics, all isolates exhibited urease, catalase, amylase and oxidase activities. Variations in terms of their ability to oxidize different sugars and citrate as carbon and energy sources were observed among the isolates. All isolates yielded negative to blood hemolysis test, indole production methyl red and Voges Proskauer tests. The temperature for the optimum growth of the bacterial isolates was at 300C. Some sttrains however, were observed to grow at 370C and 40C. All isolates were susceptible to impinem, β-lactams and β-lactam-β-lacatamase inhibitor formulations, tetracycline but resistant to meropenem. Based on the phenotypic characteristics observed, the isolates are assigned to the genus Methylobacterium.