Banca de DEFESA: ALEXSANDRA NASCIMENTO FERREIRA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : ALEXSANDRA NASCIMENTO FERREIRA
DATE: 26/08/2022
TIME: 14:00
LOCAL: Sala de aula do PPGQB
TITLE:

Production of fungal lipase and protease in low cost medium: purification, characterization and biotechnology application

KEY WORDS:

Moesziomyces aphidis; Pycnoporus sanguineus; bioprocesses; agro-industrial waste; milk coagulation

PAGES: 100
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUMMARY:

Microbial enzymes are preferred for industrial and biotechnological applications because they have characteristics and
functional capacity in extreme conditions, essential for these applications. These enzymes are used in the food,
pharmaceutical, cosmetic, biodiesel, textile, detergent, etc. Microbial enzymes can be produced in liquid or solid
bioprocesses, where residues can be used as a source of nutrients and inducers, agro-industrial residues and residual
oils, for example. Agro-industrial waste is especially used in solid bioprocesses, in addition to reducing the cost of
enzyme production, it collaborates with the reduction of environmental impacts caused by improper disposal. Since
enzymes are expensive and the reduction of their production cost becomes necessary. Therefore, in this work we aim
to produce fungal enzymes, lipases and proteases, in low-cost media, purify them and apply them. For this, in a
screening with different strains of yeasts in a liquid bioprocess, the yeast Moesziomyces aphidis was selected as the
best producer of lipase in a medium containing only residual frying oil and yeast extract for 48h. Different purification
techniques were tested to precede the chromatography, namely precipitation with ammonium sulfate, ethanol, acetone,
three-phase aqueous system and ultrafiltration. Ultrafiltration was chosen and the M. aphidis lipase was purified with
only two steps, ultrafiltration and molecular exclusion chromatography (Sephacryl S-100), with 50% final recovery. In
addition, the filament fungus Pycnoporus sanguineus was selected as a good producer of lipases and proteases in a
solid bioprocess using wheat bran. The enzymes were partially purified in ammonium sulfate fractionation, separated
into different fractions, which can be applied in chromatography and isolated separately. The resulting solid, after being
lyophilized, showed lipolytic activity and was applied in kinetic resolution reactions of racemates. The proteolytic activity
of the crude enzymatic extract (BSE) was verified against the hydrolysis of the substrates azocasein and casein. The
BSE also showed chymotrypsin and elastase activity. The effect of different protease inhibitors on enzyme activity
suggests that the P. sanguineus protease is a chymotrypsin-like serine protease. The protease from P. sanguineus
coagulated skimmed milk powder and whole liquid milk, without and with the addition of calcium. The best condition for
clotting was 120 min and 50 °C. Coagulation increased with increasing time, temperature, calcium and enzyme
concentration. This was the first P. sanguineus coagulant protease and the first filamentous fungus coagulant
chymotrypsin-like serine protease, which showed potential to be applied in the food industry in milk coagulation and
cheese making. The fermented solid with lipolytic activity also has the potential to be applied in the pharmaceutical
industry. Here we also present the first M. aphidis lipase to be purified. Enzymes with high biotechnological value and
produced in low-cost residual media

BANKING MEMBERS:
Interno - 2089586 - FRANCIS SOARES GOMES
Presidente - 1811274 - HUGO JUAREZ VIEIRA PEREIRA
Externo ao Programa - 036.711.126-89 - JOSE MARIA RODRIGUES DA LUZ - UFAL
Externo ao Programa - 1653558 - LUCIANO APARECIDO MEIRELES GRILLO
Externo à Instituição - MARCELO FRANCO - UESC-BA
Interna - 1294906 - RUTH RUFINO DO NASCIMENTO