Banca de DEFESA: PAULO HENRIQUE DA SILVA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : PAULO HENRIQUE DA SILVA
DATE: 28/06/2022
TIME: 14:00
LOCAL: google meet
TITLE:

ELECTROGENIC PIGMENTS ISOLATED FROM FUNGI OF THE CAATINGA BIOME AND SURFACTANTS APPLIED AS ELECTROCHEMICAL MEDIATORS FOR ENERGY GENERATION.

KEY WORDS:

Microbial fuel cell, fungal pigments, electrochemical mediator, bikaverin.

PAGES: 90
BIG AREA: Outra
AREA: Multidisciplinar
SUBÁREA: Biotecnologia
SUMMARY:

The microbial fuel cell (MCC) is a device that generates electrical energy from biochemical processes using microorganisms or enzymes, in its cathodic and anodic compartments, and presents itself as an environmentally friendly and viable alternative. Electrochemical mediators are substances that can reduce and oxidize (redox system), to serve as a means of transport for electrons in the MCC, optimizing the energy generation process. In this work, the production of red pigments by AspergIllus sp. UCP1349 and green by Penicillium sp. UCP1152, fungi isolated from soils of the caatinga biome, being evaluated in terms of redox properties as electrochemical mediators in a CCM. The analyzes were carried out through cyclovoltametry of the pigments with KCl and H3PO4 solutions, as support analytes, with a scanning potential of -1.0V to 1.0V, speed of 0.1Vs-1 eM, a system
composed of three electrodes: glassy carbon working electrode; against platinum wire electrode; reference electrode Ag/AgCl (KCl). The analysis results showed that the pigments present redox pairs for application as electrochemical mediators. The pigments were introduced into a 200ml cathode at three different concentrations (1mg/L, 2mg/L and 5mg/L) of CCM containing the commercial enzyme DE Trametes versicolor laccase at 200
U/L-1. The 100ml anode was filled with 20mM potassium ferrocyanide. The results obtained suggest that the very active enzymes and the isolated pigments of the studied fungi generate the future possibility of a coupled system of two or more electroactive microorganisms. Studies were conducted with the natural pigment bikaverin isolated from Fusarium oxysporum UCP 1624, with the objective of demonstrating the electroactive
capacity in electron transport, being compared with Congo red (synthetic pigment) as electrochemical mediators in a CCM. Innovative investigations were carried out with synthetic surfactants (Triton x-100, Tween 80 and Tween 20) and with polymeric biosurfactant isolated from Issatchenkia orientalis UCP1603, in order to evaluate the electron transport capacity as an electrochemical mediator, in a cathodic chamber and to evaluate a possible future application in bioremediation, considering a simultaneous action in the interior system, with energy generation in a CCM, whose results are part of an intellectual property deposit. A microbial fuel cell with cathodic and anodic compartments, both with 200 mL of volume, containing an exploded graphite plate electrode with an area of 9 cm² each was used. The cathode with a solution containing commercial Trametes versicolor laccase with 10 ppm of the analyzed substances, and an anode with a solution of potassium ferrocyanide at 20 mmol.L-1. As a cation exchange system, a 5 cm salt bridge in agar with 3M KCl was used, connecting the two compartments. The results showed an increase in the energy generation of the cells with the application of the substances studied as electrochemical mediators. Congo red stood out as the highest energy production of 273
mA.Cm-2, but it was not very stable in addition to high toxicity and degradation by laccase. Bikaverin showed a milder drop with an energy value of 230 mA.Cm-2 and an efficiency, thus demonstrating greater stability. Among the chemical surfactants, Triton x-100 showed the highest energy value of 235 mA.Cm-2, in addition to the highest stability in relation to tween 20 and tween 80. The biosurfactant showed the lowest energy response with 177 mA.Cm-2, however, its production can be associated with the possibility of future in situ production in the CCM, showing potential for long-term use.

BANKING MEMBERS:
Interna - 384972 - ANA LUCIA FIGUEIREDO PORTO
Presidente - 002.501.554-00 - GALBA MARIA CAMPOS TAKAKI - UPE
Externo ao Programa - 1646614 - MARCOS ANTONIO BARBOSA DE LIMA
Externa à Instituição - ROSILEIDE FONTENELE DA SILVA ANDRADE
Interno - 079.743.104-72 - VALDEMIR ALEXANDRE DOS SANTOS - UNICAP