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Phycoremediation of swine wastewater is a promising treatment since it efficiently removes nutrients and contaminants and, simultaneously, its biomass can be harvested and used to obtain a wide range of valuable compounds and metabolites. In this context, biomass microalgae were investigated for the phycoremediation of swine wastewater, and biomass extracts for its virucidal effect against enveloped and non-enveloped viruses. Microalgae were cultivated in a pilot scale bioreactor fed with swine wastewater as the growth substrate. Hexane, dichloromethane, and methanol were used to obtain the microalgae extracts. Extracts were tested for virucidal potential against HSV-1 and HAdV-5. Virucidal assays were conducted at temperatures that emulate environmental conditions (21 °C) and body temperature (37 °C). The maximum production of microalgae biomass reached a concentration of 318.5 ± 23.6 mgDW L−1. The results showed that phycoremediation removed 100% of ammonia-N and phosphate-P, with rates (k1) of 0.218 ± 0.013 and 0.501 ± 0.038 (day−1), respectively. All microalgae extract reduced 100% of the infectious capacity of HSV-1. The microalgae extracts with dichloromethane and methanol showed inhibition activities at the lowest concentration (3.125 µg mL−1). Virucidal assays against HAdV-5 using microalgae extract of hexane and methanol inhibited the infectious capacity of the virus by 70% at all concentrations tested at 37 °C. At a concentration of 12.5 µg mL−1, the dichloromethane microalgae extract reduced 50?80% of the infectious capacity of HAdV-5, also at 37 °C. Overall, the results suggest that the microalgae can be an attractive source of feedstock biomass for the exploration of alternative virucidal compounds. Resumo: A ficorremediação de águas residuais de suinocultura é um tratamento promissor, pois remove eficientemente nutrientes e contaminantes e, simultaneamente, sua biomassa pode ser colhida e utilizada para obter uma ampla gama de compostos e metabólitos valiosos. Neste contexto, microalgas de biomassa foram investigadas para a fitomediação de águas residuais de suínos, e extratos de biomassa por seu efeito virucida contra vírus envelopados e não envelopados. As microalgas foram cultivadas em um biorreator de escala piloto alimentado com água residuária de suínos como substrato de crescimento. Hexano, diclorometano e metanol foram usados ​​para obter os extratos de microalgas. Os extratos foram testados quanto ao potencial virucida contra HSV-1 e HAdV-5. Os ensaios virucidas foram conduzidos em temperaturas que simulam as condições ambientais (21°C) e a temperatura corporal (37°C).DW L −1 . Os resultados mostraram que a ficorremediação removeu 100% de amônia-N e fosfato-P, com taxas ( k 1 ) de 0,218 ± 0,013 e 0,501 ± 0,038 (dia −1 ), respectivamente. Todos os extratos de microalgas reduziram em 100% a capacidade infecciosa do HSV-1. Os extratos de microalgas com diclorometano e metanol apresentaram atividades de inibição na concentração mais baixa (3,125 µg mL −1 ). Ensaios virucidas contra HAdV-5 usando extrato de microalgas de hexano e metanol inibiram a capacidade infecciosa do vírus em 70% em todas as concentrações testadas a 37 °C. Em uma concentração de 12,5 µg mL -1, o extrato de microalgas diclorometano reduziu 50-80% da capacidade infecciosa do HAdV-5, também a 37 °C. No geral, os resultados sugerem que as microalgas podem ser uma fonte atrativa de biomassa de matéria-prima para a exploração de compostos viricidas alternativos. Made available in DSpace on 2022-04-11T14:01:08Z (GMT). No. of bitstreams: 1 final9878.pdf: 4339051 bytes, checksum: 95cbce0603f5f7c9f945420adecc1925 (MD5) Previous issue date: 2022

The concentration of microcystin (MC) in the Kucukcekmece Lagoon, Istanbul, Turkey, and the physicochemical and biological parameters of water quality were investigated from October 2000 to June 2003. Water samples were collected from surface waters at three sites. Most bloom samples were dominated by Microcystis aeruginosa. The major microcystin variants detected by HPLC-PDA were microcystin-YR and microcystin-LR. Microcystin concentration increased dramatically from early summer to early autumn and thereafter tended to decrease. The toxin concentration found in the filtered samples from surface waters varied between 0.06 and 24.2 microg L(-1) microcystin-LR equivalents. Each year extensive fish mortality was recorded between mid-June and early October, coinciding with heavy algal blooms. A comparison of the conditions associated with cyanotoxin episodes in 2000, 2001, and 2002 showed that the microcystin increase was related to temperature, high concentration of dissolved nutrients, high light intensity (PAR). The highest MC concentrations were recorded at temperatures between 24 degrees C and 28.5 degrees C. Field data showed that the highest MC concentration (>3 microg L(-1)) and the highest cyanobacterial biomass (>30 mg L(-1)) corresponded to a total nitrogen:total phosphorus ratio greater than 7:1. The highest concentrations of M. aeruginosa biomass (173 mg L(-1)) and MC (24.2 microg L(-1) MC-LR equiv.) and the highest salinity (8.8%) were measured concurrently in the lagoon. To our knowledge, this is the first evidence of cyanobacterial toxins in the Kucukcekmece Lagoon.

Biological degradation of cyanobacterial hepatotoxin microcystins in estuarine and coastal water samples from the Patos Lagoon estuarine system, a coastal lagoon situated at the southernmost region of Brazil, was observed. Samples of natural surface water were spiked with purified and semi-purified microcystins (MC–LR and [ d -Leu1]MC–LR) and their concentrations were monitored by HPLC analysis. After 15 days, the toxins were no longer detectable and after 43 days less than 90% of the initial concentration added to the samples was detected by ELISA. The average degradation rates and the exponential decay rate constants from inside and outside of the estuary were similar. A microcystin degradative bacterium was isolated from the estuarine region. Partial sequence of the 16S rDNA showed a 96% homology with the Burkholderia genus. This genus belongs to the beta subdivision on proteobacteria. This is the first report showing the genus Burkholderia as a cyanobacterial toxin degrader.

[D-Leu1]Microcystin-LR was identified as the most abundant microcystin from a laboratory strain of the cyanobacterium Microcystis sp. isolated from a hepatotoxic Microcystis bloom from brackish waters in the Patos Lagoon estuary, southern Brazil. Toxicity of [D-Leu1]microcystin-LR, according to bioassay and protein phosphatase inhibition assay, was similar to that of the commonly-occurring microcystin-LR, which was not detectable in the Patos Lagoon laboratory isolate. This is the first report of a microcystin containing [D-Leu1] in the cyclic heptapeptide structure of these potent cyanobacterial toxins.