| Congresso Brasileiro de Microbiologia 2023 | Resumo: 1243-2 | ||||
Resumo:Antarctica is constantly subjected to periods of freezing and thawing. Despite this harsh condition, many Antarctic microorganisms can survive these cycles of freezing and thawing, being resistant to cell damages caused by intracellular and extracellular ice formation. The aim of the proposed study is to characterize the potential of Antarctic bacteria and yeasts to tolerate freezing and their potential for antifreeze activity. The isolates were cultivated and subjected to one cycle of freezing at -18 ºC and thawing at 25 ºC to evaluate the resistance to freezing. For this, dilutions were made before and after freezing, verifying the survival rate of each isolate to the freezing and thawing cycle. After the test, the selection of isolates that had the same number of cells before and after freezing was performed. Subsequently, the positive isolates were identified by sequencing the 16S rRNA gene or the ITS region. A total of 24 freeze-tolerant isolates were obtained, including 2 yeasts and 22 bacteria from different Antarctic ecosystems, including soil samples collected in front of the Baranowski and Collins Glaciers, permafrost and moss (Collins Glacier). The greatest number of freeze-tolerant isolates were from permafrost samples. Freeze-resistant isolates were identified as belonging to the genera Acinetobacter, Arthrobacter, Pedobacter, Cryobacterium, Psychrobacter, Planococcus, Pseudomonas, Microterricola and Rhodotorula. The results obtained in this study show the existence of a great diversity of bacteria and yeasts from the Antarctic Peninsula with biotechnological potential in the production of proteins or exopolysaccharides that prevent freezing. More studies need to be carried out to characterize substances produced by microorganisms, as well as adaptations to freezing. Palavras-chave: Antarctica, freezing, microorganisms Agência de fomento:Fundação de Amparo à Pesquisa e Inovação do Estado de Santa Catarina - FAPESC | |||||