Banca de DEFESA: GUILHERME QUINTELA CALIXTO

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : GUILHERME QUINTELA CALIXTO
DATE: 14/01/2025
TIME: 14:00
LOCAL: Auditório LABTAM
TITLE:

CULTIVATION OF MICROALGAE FOR CO2 BIOFIXATION: A STRATEGY FOR CARBON CAPTURE AND CONVERSION IN BIOFUEL AND/OR BIOPRODUCTS

KEY WORDS:

microalgae, CO₂ bio fixation, greenhouse gases, biomass.

PAGES: 130
BIG AREA: Engenharias
AREA: Engenharia Química
SUMMARY:

The increase in CO₂ concentrations in the atmosphere, driven by human activities, has encouraged the search for alternative methods of carbon capture, including the use of microorganisms such as microalgae. Studies show the effect of carbon dioxide concentration on the growth of microalgae, even utilizing residual CO2 from industries like cement, which is responsible for over 7% of global CO2 emissions. The objective of this study is to evaluate the effect of various CO2 concentrations on the cultivation of two strains of microalgae: Chlorella vulgaris and Spirulina platensis, to identify their CO2 biofixation capabilities, potential high-value bioproducts, and system scaling. The microalgae were cultivated in commercial growth media—BG11 for Chlorella and Zarouk for Spirulina—under different concentrations (v/v) of CO2 (0.04%, 5%, 10%, and 15%). The microalgae were characterized by immediate analysis (ash content, moisture, volatiles, and fixed carbon), elemental analysis (CHNO), thermogravimetric analysis (TGA), X-ray fluorescence (XRF) of the ashes, lipid content, protein content, and conventional and catalytic analytical pyrolysis. Additionally, during cultivation, data on dry mass and pH were collected daily. The results show that both microalgae achieved the highest yield at a concentration of 10% CO2 (v/v), reaching 1.25 g L-1 for Chlorella and 2.15 g L-1 for Spirulina. Despite the high ash content due to the flocculation method, Chlorella showed a greater potential for biofuel production due to its high lipid content (21.7%) compared to Spirulina (11.2%). Conventional pyrolysis indicated a high amount of oxygenated (>25%) and nitrogenous (>20%) compounds for both microalgae, which were predominantly (over 90%) converted into aromatic compounds and hydrocarbons after using the HZSM-5 catalyst in the thermochemical conversion process. The analysis of system scaling for photobioreactors (80L) proved economically viable with the use of an external CO2 source, making it possible to obtain a self-sufficient system considering only the sale price of the raw microalgae.

COMMITTEE MEMBERS:
Presidente - 1979301 - RENATA MARTINS BRAGA
Interna - ***.948.834-** - KARINE FONSECA SOARES DE OLIVEIRA - UFRN
Interno - 6347420 - MARCUS ANTONIO DE FREITAS MELO
Externa à Instituição - CRISTIANE FRANCISCA DA COSTA SASSI
Externo à Instituição - RODOLFO LUIZ BEZERRA DE ARAÚJO MEDEIROS - UFRN