| Congresso Brasileiro de Microbiologia 2023 | Resumo: 1176-1 | ||||
Resumo:Most people do not have access to clean water in developing countries like Brazil. The ingestion of contaminated water is associated with several diseases, among which diarrhea is the most frequent and especially those associated with pathogenic types of Escherichia coli. Alternative forms of water disinfection, mainly with low-toxicity and affordable agents, are important for human health. This work aimed to evaluate, in an unprecedented way, the disinfection efficiency of aqueous extracts of whole Moringa oleifera seeds, as well as a system with blue light directed at total coliforms and E. coli in water samples from naturally contaminated sources. Although the literature has shown the antibacterial action of Moringa oleifera and blue light, data are scarce and even non-existent regarding blue light and without assessing the potential of these agents in the treatment of drinking water. The methodology to evaluate the efficiency of these new agents in the disinfection of water was carried out at the Laboratory of Microbiology and Technological Bioprospection (LMBT) of DECBI/ICEB/UFOP with a protocol created from the Quanti-Tray/2000 Colilert IDEXX technique with the new approach for the test comparison of the quantitative determination of E. coli in fresh water – control before treatment and after treatment with the agents. After reading, MPN of total coliforms and E. coli are calculated by the IDEXX MPN Generator software, with 95% reliability. Water treatment with Moringa oleifera was done with 200mg/mL of whole seeds under agitation for 4 hours. For the treatment of water with blue light, the Blue Light Water Disinfection Apparatus (ADALA) was used, manufactured in a glass bottle with a diameter of (16.0 ± 0.5) cm and a height of 11 cm, containing a beaker to receive the test water. In the internal part of the equipment, a 12 V and 2 A LED strip was initially installed, in a spiral shape. Treatment was performed with a radiance of 20 μW/cm2 and also with a radiance of 60 μW/cm2, for 15 min, 30 min, 1 h, 2 h, 5 h, and 8 h. In parallel, a treatment trial with 2% sodium hypochlorite was also carried out using the same water as the other tests to be the standard reference test, allowing the comparative evaluation of the disinfectant potential of the new agents. The results obtained were quite encouraging. There was a reduction of 2 log 10 of E. coli MPN/100mL of fresh water treated by Moringa oleifera in relation to the 691 E. coli MPN /100mL of the control sample. And for the treatment with blue light, the best result was obtained after treatment under 60 μW/cm radiance with a 100% reduction of E. coli both after 5h and 8h in relation to the control sample containing 691 MPN of E. coli/ 100mL of water. It was concluded that the new agents were fully effective in disinfection with the unprecedented highlight of blue light in the inactivation of total coliforms and E. coli in water, with an ideal dose of 738 J/cm2. In addition, the reading of the cards of water treated by blue light remained without any contamination even after 2 months of the first reading, while the test cards of Moringa oleifera and even those of the reference test of water treatment with sodium hypochlorite at 2% the inactivation of total coliforms and E. coli contaminating the water was reversible after this period. The results are indicative of good prospects for future applications. Palavras-chave: blue light, moringa oleifera, water desinfection, extracts Agência de fomento:UNIVERSIDADE FEDERAL DE OURO PRETO | |||||