Banca de QUALIFICAÇÃO: JÉSSICA RENALY FERNANDES MORAIS

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : JÉSSICA RENALY FERNANDES MORAIS
DATE: 08/05/2024
TIME: 14:00
LOCAL: Via Google Meet
TITLE:

PRODUCTION OF CROSS-CROSS-CUT ENZYME AGGREGATES (CLEAs) USING COMMERCIAL CELLULOLYTIC ENZYME COCKTAILS

KEY WORDS:

 Immobilization; enzyme; cellulase; magnetic nanoparticles

PAGES: 90
BIG AREA: Engenharias
AREA: Engenharia Química
SUBÁREA: Processos Industriais de Engenharia Química
SPECIALTY: Processos Bioquímicos
SUMMARY:

Enzymes play an important role in biotechnological processes. However, to be industrially profitable, they need to allow easy handling, reuse, and operational stability. One way to ensure the efficiency and these characteristics of soluble enzymes is through the immobilization technique. The strategy of cross-linked enzyme aggregates (CLEAs) is particularly interesting because it allows direct contact of the enzyme with the substrate, due to the absence of solid supports in the immobilization process, or through the use of non-porous supports, such as magnetic nanoparticles, for the formation of magnetic CLEAs (mCLEAs). Among industrial enzymes, cellulases are a set of enzymes capable of hydrolyzing isolated cellulose or cellulose present in biomass, converting it into glucose, a product of interest for the production of lignocellulosic, or second-generation (2G) ethanol. Therefore, the present study aims to produce CLEAs from commercial cellulolytic cocktails (Celluclast and Cellic CTec 2). These cellulolytic cocktails are widely used in the hydrolysis of lignocellulosic materials, forming part of the 2G ethanol production chain. Initially, different precipitation agents were studied, such as ethanol (99.5%), acetone (a. grade), and saturated ammonium sulfate solution, using 5% glutaraldehyde (v/v) and magnetic nanoparticles covered with Aminopropyltriethoxysilane (APTES) for the production of CLEAs and mCLEAs, respectively. With the biocatalysts obtained, evaluation was carried out based on immobilization parameters, such as precipitation yield and recovered activity of precipitating agents, as well as the catalytic capacity of CLEAs and mCLEAs using different substrates, Carboxymethylcellulose (CMC) and Filter paper (FP), which allows obtaining the activities of endo-cellulases (CMCase) and total (FPase), respectively. The precipitating agents that proved to be most efficient were ethanol and acetone. The activity recovered for ethanol was 27.25 ± 1.67% (CMCase) and 100 ± 14.63% (FPase) for the Celluclast cocktail and 41.96 ± 3.66% (CMCase) and 14.29 ± 2.01% (FPase) for Cellic CTec 2. With acetone, it was possible to recover 34.24 ± 1.45% (CMCase) and 77.66 ± 7.83% (FPase) when using the Celluclast cocktail and 38 .59 ± 3.21% (CMCase) and 55.41 ± 12.61% (FPase) for Cellic CTec 2. From the evaluation of the enzymatic activity of CLEAs with the addition of the additive Bovine Serum Albumin (BSA) in the precipitation, it was possible to define acetone as the best precipitating agent. CLEAs precipitated with acetone and BSA achieved the best activity results, being 287.27 ± 42.59 U/g (CMCase) and 0.035 ± 2.059 U/g (FPase) for Celluclast and 425.37 ± 48.11 U/g (CMCase) and 1.54 ± 1.10 U/g (FPase) for Cellic CTec 2. To facilitate the separation process and foresee future use in an industrial environment, magnetic nanoparticles coated with APTES were added to the precipitation stage, producing magnetic CLEAs (mCLEAs). The mCLEAs that showed the best results were those produced with the Celluclast enzyme with BSA as an additive, showing activities of 149.65 ± 2.65 U/g (CMCase) and 5.30 ± 1.75 U/g (FPase). Therefore, it is highlighted that it was possible to efficiently produce CLEAs and mCLEAs using commercial cellulolytic enzyme cocktails, which could be applied in the hydrolysis stage of pretreated lignocellulosic biomass aiming at the production of 2G ethanol.

COMMITTEE MEMBERS:
Presidente - 1346198 - EVERALDO SILVINO DOS SANTOS
Interno - 3304882 - CARLOS EDUARDO DE ARAÚJO PADILHA
Interna - 3214434 - NATHALIA SARAIVA RIOS
Externa à Instituição - PETRÚCIA KARINE SANTOS DE BRITO BEZERRA - IFRN