| Congresso Brasileiro de Microbiologia 2023 | Resumo: 912-1 | ||||
Resumo:Characterized as extremophiles or extremotolerant, microorganisms that inhabit environments under strong selective pressures are selected due to a variety of mechanisms. These mechanisms include the formation of biofilms, the release of specialized metabolites, or a high potential for DNA repair. In this context, devices that bring together such characteristics of extreme environments are solar or photovoltaic panels. These panels have revealed, on their surface, the presence of highly diverse microbial communities. The microorganisms isolated
from photovoltaic panels mostly exhibit pigmentations that suggest their role in protecting them against harmful radiation and oxidative stress. Due to this potential, the resistance of strains isolated from photovoltaic panels to germicidal ultraviolet light (UVC) was evaluated at different time intervals. Notably, the study by our research group, which has already been published,
marks the first time in Brazil when microorganisms isolated from solar panels were identified and compared with microbiota from other continents. Surprisingly, despite the different geography and climatic conditions, the results were similar. To continue this research, non-pathogenic pigmented microorganisms were selected, including: PSR 33 Microbacterium hydrotermale, PSR 37 Arthrobacter koreensis, PSR 46 Gordonia sp., PSR 51 Kocuria sp., PSR 34 Rhodotorula mucilaginosa and PSI 72 Rhodotorula sp. In order to determine their resistance to germicidal light (λ= 254nm), a broad-spectrum lamp was used at distances of 10 and 33 cm from the samples, with exposure times varying from 0 to 10 minutes. The inoculums were standardized at 106, 107, and 108 CFU/ml, and then aliquots were seeded in a petri dish containing agar (TSA for bacteria and Sabouraud for yeasts), which were incubated in the dark at 35°C and 25°C, respectively. The tests were performed in triplicate, and the positive controls
included inoculums of pigmented microorganisms at 0 seconds, and inoculums of E. coli and S. aureus, while only agar was used as a negative control. The results showed that at a standardization of 106, no microorganism was able to grow. At 107, the following growth patterns were observed: PSR 33 at 10 cm for 2 minutes and at 33 cm for up to 8 minutes; PSR 37 at 33 cm for up to 8 minutes; PSR 46 at 10 cm for 2 minutes and at 33 cm for up to 6 minutes; and PSR 51, PSR 34, and PSI 72 at 33 cm for up to 10 minutes. At 108, the pigmented microorganisms grew under all conditions of distance and time, but with a gradual reduction of
UFC/ml. The positive controls were able to grow, while the negative controls did not. It appears that these microorganisms mostly possess yellow and orange pigmentation, which may be related to the production of carotenoids, pigmented and liposoluble compounds synthesized by both microorganisms and plants. Studies suggest that these pigments act to protect microorganisms against radiation, similar to how they protect chlorophyll during photosynthesis. Given the resistance of these microorganisms under UVC light, their biotechnological potential should be considered. Palavras-chave: Microorganisms, UVC, Photovoltaic panels Agência de fomento:CAPES – Coordenação de Aperfeiçoamento de Pessoal de Nível Superior | |||||