Banca de DEFESA: Kelly Assis Rodrigues

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : Kelly Assis Rodrigues
DATE: 14/09/2022
TIME: 14:00
LOCAL: Videoconferência
TITLE:

"Evaluation of lovastatin production in Aspergillus sp., hyaluronic acid in Ogataea polymorpha and 2’-Fucosyllactose in Kluyveromyces lactis."

KEY WORDS:

Filamentous fungus; statin; yeast; biopolymer; oligosaccharide; human milk

PAGES: 144
BIG AREA: Ciências Biológicas
AREA: Biologia Geral
SUMMARY:

The use of microorganisms for the production of biomolecules has been attracting more and more commercial interest. During the development of this work, three microbial processes were evaluated for the production of lovastatin and Hyaluronic Acid and 2'Fucosyllactose. Lovastatin is a biomolecule naturally produced by some fungi, especially Aspergillus terreus. It is a molecule that acts as a competitive inhibitor of a key enzyme in the cholesterol pathway, 3-hydroxy3-methyl-glutaryl-Coenzyme A (HMG-CoA) reductase, contributing to the reduction of hypercholesterolemia. As Brazil has a vast biodiversity, the production of lovastatin in fungi of the genus Aspergillus isolated in Brazilian territory was evaluated, as well as the genomic diversity of these fungi. Thus, a strain was identified, URM 5961, which presented a production of 0.6 g/L and a high degree of genomic identity with the reference strain, ATCC 20542, which produces about 1.0 g/L of lovastatin. Hyaluronic acid (HA) is a biopolymer naturally produced by animals and some microorganisms. Due to its rheological characteristics such as high viscosity, hygroscopicity and biocompatibility, HA is widely used in ophthalmological treatments, facial fillers and in the formulation of cosmetics. Obtaining HA from natural sources was originally from animal tissue, such as rooster comb or, by bioproduction by pathogenic bacteria of the genus Streptococcus, but these sources have been replaced by heterologous production in other microorganisms, such as Bacillus subtilis. As Ogataea polymorpha has been gaining importance as an organism for heterologous expression, this work aimed to investigate its potential as a host for the production of HA. For this purpose, three strains were generated, EMB 102, EMB 103 and EMB 104, which differ in terms of the promoters used to guide the introduced genes. We confirmed the ability of O. polymorpha to produce HA, in which strain EMB 103 showed a production of 0.8 mg/mL. These results open the way for future investigations to improve the production of these compounds. The 2'Fucosyllactose (2'FL) is a human milk oligosaccharide (HMOs) consisting of three monosaccharides: glucose, galactose and fucose, corresponding to 80% of the HMOs. The 2'FL has immunomodulatory activity acting on inflammatory processes, decreasing interactions between pathogens and the gastrointestinal mucosa in newborns. The K2WΔSacII strain was constructed using the Kluyveromyces lactis yeast where the gmd and fcl genes from Escherichia coli and the WcfB gene from Bacteroides fragilis were inserted so that it was able to produce 2'FL using lactose and hydrolyzed açaí seed as a substrate. mostly by mannose. The objective of this work was to characterize the K2WΔSacII strains in terms of 2'FL production and improve this production by disrupting the lac4 gene that encodes β-galactosidase. Possible reasons for this not to have occurred, in addition, the disruption of the lac4 gene was performed, confirmed by the expected phenotype of the yeast losing the ability to grow on lactose as the only carbon source. This opens the way to proceed with the project, aiming at the production of 2'FL in K. lactis.

BANKING MEMBERS:
Externo à Instituição - ANTÔNIO MILTON VIEIRA GOMES - USP
Externo à Instituição - FELIX GONÇALVES DE SIQUEIRA - EMBRAPA
Presidente - 1972136 - NADIA SKORUPA PARACHIN
Externa à Instituição - NADIELLE TAMIRES MOREIRA MELO UMPIERRE
Externa ao Programa - 2095134 - PATRICIA ALBUQUERQUE DE ANDRADE NICOLA