25º Congresso Brasileiro de Microbiologia

25º Congresso Brasileiro de Microbiologia

ResumoID:560-1

Área: Microbiologia Geral e Meio Ambiente ( Divisão L )

GENETIC DIVERSITY OF METHYLOTROFIC BACTERIA ISOLATED FROM MANGROVE SPECIES AND THEIR TOLERANCE TO HEAVY METALS

Manuella Nóbrega Dourado (ESALQ - USP); Anderson Ferreira (ESALQ - USP); Welington Luiz Araújo (ESALQ - USP); Itamar Soares Melo (CNPMA); João Lúcio Azevedo (ESALQ - USP); Paulo Teixeira Lacava (ESALQ - USP)

Resumo

The high biological productivity of the mangrove ecosystem demands a high nutrient availability at the beginning of the trophic chain. Microorganism activities are essential in the organic matter decomposition process and nutrient fixation. Bacteria species adapted to the mangrove conditions present a potential source of new biotechnologies resources, such as bacteria species that produce valuable enzymes. The genus Methylobacterium is comprises the PPFMs (pink-pigmented facultative methylotrophic) bacteria. These bacteria can fix nitrogen, nodulate the host plant, produce cytokinin (a plant hormone) and enzymes such as pectinase and cellulose, as well as be used on the bioremediation of polluted environments due to its metal tolerance. These characteristics make Methylobacterium spp. important genus for plant growth promotion. To further examine these characteristics, Methylobacterium spp. were isolated from the mangrove species such as Rhizophora mangle, Laguncularia racemosa and Avicenia sp. as endophytic bacteria. Samples of mangrove species were collected in Bertioga, São Paulo, Brazil, from locations either contaminated and uncontaminated by oil spills. The tolerances of the isolates to different heavy metais were assessed by exposing them to cadmium (Cd), lead (Pb) and arsenic (As) in different concentrations (0,1mM, 0,5mM, 1mM, 2mM, 4mM and 8mM). Additionally, the genetic diversity of Methylobacterium spp. by the sequence analysis of the gene 16S rRNA (ribosomal RNA gene). The isolates from the oil spill locations were grouped, suggesting that oil can select microorganism that tolerate oil compounds and change the methylotrophic bacteria community. Cadmium is the most toxic heavy metal assessed in this work followed by arsenic and lead, and two isolates that are tolerant to cadmium, lead and arsenic. These isolates have the potential to be used to biorremediate mangrove environments that are contaminated by oil spills by immobilizing heavy metals present in the oil.

Palavras-chave: Bacteria Diversity, Endophytes, Methylobacterium, 16S rRNA

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