Banca de DEFESA: CLEDSON BARROS DE SOUZA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : CLEDSON BARROS DE SOUZA
DATE: 15/09/2022
TIME: 14:00
LOCAL: Sala de Reuniões do IQB
TITLE:

Production, isolation and characterization of laccase-like and caseinase from Amphobotrys ricini obtained by solid
state fermentation

KEY WORDS:

Amphobotrys ricini; Laccase; Serine protease; Caseinase; Isolation; Characterization. Collagenase.

PAGES: 80
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUMMARY:

The species Amphobotrys ricini is a filamentous ascomycetous fungus that is widespread in different regions of Brazil
that has saprophytic and phytopathogenic growth, being very important economically due to its destructive capacity
when producing gray mold in castor bean cultivars. Although extensively studied in relations with its preferred host
and knowing the presence of activities of lipases, proteases, pectinases, cellulases, malic enzymes, superoxide
dismultases, cutinases and esterases, only one endoglucanase was studied in more detail, being isolated and
characterized . In order to know which activities the fungus presents, it was induced in a petri dish in the production of
lignolytic enzymes and the inoculum was applied on residues and by-products of sugar cane, wheat, coconut and
wood. It showed a more accentuated growth on sugarcane residue, where it produced relevant enzyme with laccaselike activity, which was partially isolated through a route composed of acid extraction with chelator, saline
fractionation, dialysis and ion exchange chromatography. Another route stands out as a pre-purification process from
an extraction at basic pH followed by application in a three-phase aqueous system, showing greater recovery than the
first route, becoming promising as an alternative isolation route. No other ligninase activity was detected. A. ricini also
showed significant growth on wheat residue, showing great caseinolytic activity and casein clot formation in
reconstituted bovine milk. The extraction of this activity was performed with metallic chelator in an acid medium and in
a basic medium without chelators, where the latter stands out as the most favorable condition, presenting a promising
pre-purification route that consists of submitting the extraction to a twophase aqueous system with greater recoveries
than three-phase systems and saline fractionation. Caseinolytic activity was completely inhibited by PMSF, indicating
that the fungal caseinases are serine proteases. In the caseinolytic extract, low trypsin, chymotrypsin and elastase-2
activities were detected. The partially purified enzymes have caseinolytic and collagenolytic activity, activities that can
be used in the manufacture of dairy products and in the production of cicatrizating drugs, respectively. Partially
isolated laccase-like is still an enzyme with potential application in several fields, except for the decolorization of liquid
dyes or the sterilization of medical utensils.

BANKING MEMBERS:
Presidente - 1811274 - HUGO JUAREZ VIEIRA PEREIRA
Interno - 2089586 - FRANCIS SOARES GOMES
Externo ao Programa - 036.711.126-89 - JOSE MARIA RODRIGUES DA LUZ - UFAL
Externo ao Programa - 1653558 - LUCIANO APARECIDO MEIRELES GRILLO
Externo ao Programa - 1488396 - TICIANO GOMES DO NASCIMENTO
Externo ao Programa - 1653165 - VALTER ALVINO DA SILVA