Banca de QUALIFICAÇÃO: WYDEMBERG JOSÉ DE ARAÚJO

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : WYDEMBERG JOSÉ DE ARAÚJO
DATE: 25/01/2021
TIME: 14:00
LOCAL: Videoconferência
TITLE:

IMPLICATIONS OF THE CULTIVATION MEDIUM AND THE HYDROPHOBIC SUBSTRATE IN OBTAINING MICROBIAN CONSORTIA

KEY WORDS:

Biodegradation, biotechnology, petrochemical waste, consortia, metagenomics, production water, biosurfactant

PAGES: 87
BIG AREA: Ciências Biológicas
AREA: Bioquímica
SUMMARY:

Different wastes produced by the petrochemical industries have an environmental impact. Biotechnological approaches offer promising alternatives for treating these residues in a sustainable way. Through the use of biosurfactants as adjuvants, microorganisms clean up the waste by degrading the hydrocarbons present in the waste. In order to select microbial consortia from a sample of drilling waste and production water (AP) from an oil reservoir, it has been demonstrated that by using heavy oil as a carbon source, it enriches microorganisms and genes involved in the degradation of recalcitrant hydrocarbons through biosynthesis of biosurfactants. Four consortia were obtained, two from the AP, one enriched in Yeast extract peptone dextrose (YPD consortium) and the other using only the Bushnell-Haas mineral medium (BH consortium) with heavy oil. Two other consortia from drilling rock enriched in rich medium Luria Bertani (LB), consortia R1 and R2. Sequences of metagenomic DNA showed that regardless of the methodology, there were losses of diversity in the microbial communities enriched in the consortia. Even so, the consortia enriched in nutritional means YPD and LB showed greater diversity than the consortium BH, which is predominantly composed of members of the genus Brevibacillus. The functional annotation revealed that the BH consortium was enriched with genes involved in the synthesis of biosurfactants, while the YPD, R1 and R2 consortia present a greater abundance of recalcitrant hydrocarbon degradation genes. The comparison of these consortia with others available in public databases confirmed the enrichment of low molecular weight biosurfactant genes in the BH consortium and that this consortium has a high cellular hydrophobicity and formation of stable emulsions, suggesting that the absorption of oil by microorganisms can be favored by biosurfactants. In contrast, the YPD, R1 consortia were more efficient in reducing the interfacial tension. Despite these differences between consortia, oil biodegradation analyzes performed by gas chromatography showed few significant differences in relation to hydrocarbon degradation rates. Specifically, the YPD consortium showed higher degradation rates of C12 to C14 alkanes, while the BH consortium showed a significant increase in the degradation of some polycyclic aromatic hydrocarbons (PAHs). These data suggest that the enrichment of biosurfactant genes in the BH consortium could promote a more efficient degradation of hydrocarbons, despite their lower taxonomic diversity compared to the consortium enriched in YPD medium. In addition, all consortia showed efficient degradation of long recalcitrant hydrocarbons and PAHs. Together, these results showed that cultivation in a minimal medium supplemented with heavy oil was an efficient strategy in the selection of microorganisms that produce biosurfactants and degradation of compounds that are difficult to degrade, evidencing the biotechnological potential of these bacterial consortia in the treatment of residues and in the bioremediation of impacted areas.

BANKING MEMBERS:
Externo à Instituição - CELSO JOSÉ BRUNO DE OLIVEIRA - UFPB
Interna - 1453487 - KATIA CASTANHO SCORTECCI
Presidente - 2261797 - TIRZAH BRAZ PETTA LAJUS