Banca de DEFESA: JOYCE CAMILA BARBOSA DA SILVA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : JOYCE CAMILA BARBOSA DA SILVA
DATE: 04/10/2023
TIME: 16:00
LOCAL: Sala Virtual do Google Meet (https://meet.google.com/xhr-rmgo-kwr)
TITLE:

IDENTIFICATION OF CONTAMINATING FILAMENTOUS FUNGI IN OPEN TREATMENT SYSTEM BY MICROALGAE

KEY WORDS:

molecular identification, PCR, bioremediation, microalgae-fungus, symbiosis

PAGES: 61
BIG AREA: Engenharias
AREA: Engenharia Ambiental
SUBÁREA: Saneamento Básico/Esgotos/Reator Anaeróbico
SUMMARY:

Inadequate disposal of effluents from dairy industry can degrade the environment due to the high level of pollutants. Therefore, it is necessary to treat this effluent before releasing it into water bodies, however, physical-chemical treatments generally applied to this type of effluent are highly expensive, making it unfeasible for small and medium-sized industries. In this context, biological processes gain prominence due to the simplicity of their application and economic viability. Compared to traditional biological treatment strategies, the use of microalgae has advantages such as greater nutrient consumption capacity, mainly nitrogen and phosphorus, and they are generally cultivated in open systems, which have higher risk of contamination by other microbiological groups. In view of this, the symbiotic relationship between algae and fungi is highlighted as this association facilitates the harvesting of algae by copelletizing them into fungus pellets and can increase the efficiency of the treatment. Therefore, the present work aimed to characterize filamentous fungi isolated during the tertiary treatment process of cheese whey by microalgae of the species Tetradesmus obliquus LCE-01 in open system. The treatment system by Tetradesmus obliquus LCE-01 was composed of open reactors using residual effluent with organic loads (chemical oxygen demand) between 1000-4000 mg L^-1, magnetically stirred, during 15 days of process, maintained at 30-35ºC and pH 7.5- 8.0 with one-sided illumination of 100 µmol m^-2 s^-1. Reactor samples were collected after vigorous microbial growth in the reactor (log CFU/mL between 9-10) and inoculated by spreading in Petri dishes with PDA medium (potato dextrose agar) in dilutions 10^-2, 10^-4 and 10^-6, in order to favor the growth of isolated colonies. The isolated colonies were transferred using a nickel and chromium loop to Petri dishes containing PDA where they were allowed to develop alone. For macroscopic characterization, pieces of the colonies were homogenized in 0.1% peptone water and re-inoculated in Petri dishes to observe the development of the colonies from their spores, characterizing their mycelia. For microscopy, slides were prepared with pieces of the fungal mycelium and stained with lactophenol blue (cotton blue) in order to visualize the fungal hyphae and reproductive structures. Molecular (genetic) characterization was carried out following the steps of DNA extraction, amplification and sequencing using the primers ITS (internal transcript spacer) (1 and 4) and beta-tubulin (β-tub or BT) (2a, 2b, T1 and T2), data editing and phylogenetic analysis using CodonCode Aligner® Software, GenBank database and MEGA X program ®.  It was possible to isolate 9 fungal strains, which after a few generations of replication only remained viable for cultivation in the laboratory 5 (F2, F4, F5, F6 and F10), which were used for the characterization steps. Regarding the macroscopic characteristics of the colonies and microscopic characteristics of the mycelium/hyphae, it was noticed that the F2 fungus had olive-green sporulating colonies, a cottony surface, white and circular margins, and a black reverse color with a wrinkled center. Thin, septate, and branched hyphae and ellipsoid-shaped and irregular conidia were visualized, possibly characterizing a Cladosporium genus. The F4 fungus had white colonies that turned yellow over time with a granular surface, white and circular border with reverse color. The fungus had hyaline, thin, non-septate and spiral hyphae. The F4 genus possessed the characteristics of an Epidermophyton. The F5 fungus presented white colonies and, after sporulation, a pinkish tone, a cottony surface with an irregular white border and a yellowish-white reverse color. The fungus had spiral, hyaline and thin hyphae with oval/round microconidia, which characterized a fungus of the genus Trichophyton. The F6 fungus presented white mycelium, a cottony surface, a white and circular border, and a yellow reverse color; with non-septate, branched and hyaline hyphae with globose and intercalary conidia, probably linked to the genus Chrysosporium. Finally, the fungus F10 demonstrated brown colonies in the center, green in the inner part and with white edges, granular surface and reverse coloration of the black colony, with septate and hyaline hyphae, branched near the apex with a group of phialides with conidia and conidiospore characteristic of the genus Penicillium. The 5 fungi, if the genera are confirmed, are from the ascomycete phylum. Regarding molecular characterization to confirm the genus, and consequently the species, the extraction of fungal DNAs and amplification were achieved using the ITS and BT primers. However, the genetic material was sent for sequencing, which would enable the construction of the phylogenetic tree of the fungi, and the results were not received at the time of defending the dissertation, but will be in the final version of the manuscript. The isolation and characterization of fungi that naturally perform symbiosis with microalgae opens up space, mainly in the treatment of effluents, but also in other biotechnological areas that can involve the use of their biomass as biofuels and biofertilizers.

COMMITTEE MEMBERS:
Presidente - 3081569 - CARLOS EDUARDO DE FARIAS SILVA
Interno(a) - 1644323 - KARINA RIBEIRO SALOMON
Externo(a) ao Programa - 1296115 - ALBANISE ENIDE DA SILVA - UFALExterno(a) à Instituição - ANA KARLA DE SOUZA ABUD - UFS