Banca de QUALIFICAÇÃO: KAMILLA KARLA DA SILVA BARBALHO

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : KAMILLA KARLA DA SILVA BARBALHO
DATE: 29/03/2021
TIME: 09:00
LOCAL: Videoconferencia - Link para acesso: meet.google.com/fkw-vnpf-xzw
TITLE:

More than oil: prospecting the potential biotechnological of communities and bacterial isolates of the Brazilian pre-salt

KEY WORDS:

Brazilian pre-salt, biodegradation, metagenomic, oil, microorganisms.

PAGES: 146
BIG AREA: Ciências Biológicas
AREA: Bioquímica
SUMMARY:

The oil industry represents one of the largest and most relevant sectors of global industry. In Brazil, the discovery of the pre-salt reservoirs placed the country among the largest oil producers in the world. In general, oil reservoirs have high toxicity, hydrophobicity, temperature and pressure. In addition to these characteristics, the Brazilian pre-salt reservoirs have a high concentration of carbon dioxide (CO₂). It is known that reservoir microorganisms are able to degrade oil and be applied in processes such as bioremediation. The objective of this work was to investigate the biotechnological potential of pre-salt bacterial communities and isolates under high CO₂ conditions.  For this purpose, from a sample of pre-salt oil, six consortia were obtained, organized in two groups: three undefined microbial consortia obtained at high CO₂ concentration and the other three obtained from the same sample, but without high concentrations of the gas. The latter group was subsequently subjected to high CO₂ concentrations. From the consortia, 19 bacterial isolates were obtained. To evaluate the biotechnological potential of the consortia, the following tests were performed: i) production of biosurfactants, from the oil dispersion and emulsification index (E24%) tests; ii) growth curve and iii) taxonomic and functional characterization from metagenomic sequencing. For the isolates the following assays were performed: i) hydrocarbon degradation capacity by the 2,6 - DCPIP test; ii) cellular hydrophobicity and iii) enzymatic activity of hydrolases. The functional assays of the consortia showed that three are able to produce biosurfactant molecules capable of generating emulsion, whereas none of the consortia is able to disperse oil. The growth curves showed that five are able to grow in the absence of external carbon sources. This indication of inorganic carbon fixation was proven by sequencing of the consortia and the presence of reads for the genus Ochrobactrum capable of fixing carbon. Within the consortia, the most abundant phyla were Proteobacteria, Actinobacteria, and Firmicutes, with the consortia subjected to CO₂ being more diverse than the consortia obtained at high CO₂ concentration. Metabolically, the most enriched pathways in the consortia established in CO₂ were the amino acid metabolism and carbohydrate metabolism pathways. As for the isolates, nine were characterized and tested. Of these, five were able to degrade between 50% and 80% of the xylene and toluene fractions, and another eight degraded 100% of the gasoline, diesel, and kerosene fractions. The isolate SGC14 showed the best result for degradation of multiple carbon sources. The data point to a disfavor of biosurfactant production by undefined microbial consortia at high CO₂ concentrations. The high hydrophobicity of the isolates, the low performance of the consortia in biosurfactant production, together with the production assays of the lipase and esterase hydrolases by the isolates, indicate the use of the enzyme apparatus as the main degradation strategy for microorganisms indigenous to pre-salt oil. It is concluded that isolates and microbial consortia from pre-salt oil show promise in hydrocarbon degradation and as suppliers of biotechnological products with industrial potential.

BANKING MEMBERS:
Presidente - 1997012 - RAQUEL CORDEIRO THEODORO
Interno - 1507794 - RODRIGO JULIANI SIQUEIRA DALMOLIN
Externa à Instituição - ANA LÚCIA FIGUEIREDO PORTO - UFRPE