Banca de QUALIFICAÇÃO: FRANCISCO BRUNO FERREIRA DE FREITAS

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : FRANCISCO BRUNO FERREIRA DE FREITAS
DATE: 02/02/2024
TIME: 14:00
LOCAL: Via Google Meet
TITLE:

BIODEGRADATION OF 2-METHYL-NAPHTHALENE AND PHEANTHRENE BY PSEUDOMONAS AERUGINOSA IN MICROCOSMS - INFLUENCE OF THE DISPERSANT

KEY WORDS:

Biodegradation, phenanthrene, 2-methyl-naphthalene, Pseudomonas aeruginosa, biosurfactants

PAGES: 75
BIG AREA: Engenharias
AREA: Engenharia Química
SUBÁREA: Processos Industriais de Engenharia Química
SPECIALTY: Processos Bioquímicos
SUMMARY:

Oil stands out as one of the main raw materials for modern society, and can be part of the constitution of materials, ranging from fuels to medicines. Knowing this great importance, the search for its extraction and refining is more frequent every year, causing oil spills in soils and oceans. Because of their carcinogenicity and mutagenic aspects, some polycyclic aromatic hydrocarbons (PAHs) pose risks to humans and wildlife, such as 2-Methylnaphthalene (2-MN) and phenanthrene. Therefore, knowing the problems that oil and its hydrocarbons can cause if spills occur, it is necessary to look for solutions, such as the biodegradation of petroleum compounds in marine environments, which is based on the ability of microorganisms to degrade petroleum compounds. A factor that hinders the microbiological decomposition of oils and derivatives, when a hydrocarbon spill occurs, is the hydrophobicity of the molecules, which is why the industry invests in the development of dispersants that reduce surface tension at the hydrocarbon/water interface. In this context, the literature has demonstrated the advantages of biosurfactants (surfactants of biological origin) in relation to surfactants from the chemical industry. Thus, the main objective of the present study is to evaluate the biodegradation capacity of 2-Methylnaphthalene and Phenanthrene (model hydrocarbons) by Pseudomonas aeruginosa in the presence of industrial biosurfactant (dispersant) with cultivation in microcosms. The biosurfactant (dispersant) was provided by a chemical industryand was characterized based on surface tension and emulsification index analyses. The degradation of the hydrocarbons was subsequently carried out, varying the concentration of the hydrocarbons and the biosurfactant for 10 days, monitoring pH, bacterial growth, rhamnolipid concentration and biodegradation rate. The degradation of the mixture of 2-Methylnaphthalene (2-MN) and phenanthrene was also evaluated, with the aim of evaluating the strain's ability to degrade mixtures of hydrocarbons. The results demonstrate that the industrial biosurfactant presented satisfactory emulsification index results for toluene and lubricating oil, presenting values above 40% for concentrations of NaCl added and in small concentrations of biosurfactant, presenting these values after 240 hours of cultivation. The bacterium Pseudomonas aeruginosa was able to degrade phenanthrene, being able to degrade up to 61.43%. It is also observed that the industrial biosurfactant improved the biodegradation rate, being the only variable that had a significant influence on the studied response. The model presented based on the results of the statistical analysis presented 92% of the data explained by it.

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