Banca de DEFESA: NAIANY SILVA DE MEDEIROS

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : NAIANY SILVA DE MEDEIROS
DATE: 09/06/2023
TIME: 14:30
LOCAL: Link de acesso para videoconferência: https://meet.google.com/pdz-xheb-xxm
TITLE:
Evaluation of the biotechnological potential of lactic acid bacteria to produce bioemulsifiers, bacteriocins and lipase

KEY WORDS:
 Lactobacillus; emulsion; antidiabetic activity; antimicrobian.

PAGES: 86
BIG AREA: Ciências da Saúde
AREA: Farmácia
SUMMARY:
Lactic acid bacteria (LAB) are a diverse group of microorganisms consisting of Gram-positive
rods or cocci, generally recognized as safe microorganisms (GRAS). During fermentation, LAB
produces lactic acid as the main product and several bioactive metabolites, which have
antioxidant, antidiabetic, antimicrobial, and emulsifying activities. Therefore, the present study
aims to evaluate the biotechnological potential of Lacticaseibacillus paracasei regarding the
production of biosurfactants/bioemulsifiers, lipase and bacteriocins. Initially, four strains of
LAB were screened for their ability to produce biosurfactants/bioemulsifiers: Lactobacillus
acidophilus NRRL B-4495, Lactiplantibacillus plantarum NRRL B-4496, Lacticaseibacillus
rhamnosus EM1107 and Lacticaseibacillus paracasei Shirota. The strain L. paracasei was
selected to study the conditions for the production of biosurfactants/bioemulsifiers. Then, a
central rotational composite design (DCCR) 22 was performed to evaluate the influence of
glycerol concentration and initial pH on optical density at 600 nm (DO600 nm) and emulsification
index after 24h (IE24%). Culture supernatants from L. paracasei were evaluated for in vitro
antimicrobial activity (against Staphylococcus aureus, Escherichia coli, Burkholderia cepacia
and Burkholderia multivorans), in vitro antioxidant activity, in vitro antidiabetic activity, and
were also evaluated for the presence of lipolytic activity. In addition, a DCCR 23 was performed
to evaluate the influence of lactose, peptone concentration and initial pH on bacteriocin
production. The results showed that glycerol concentration and pH in the studied range did not
interfere on optical density at 600 nm (DO600 nm). Regarding IE24, the maximum response was
obtained using 4.8% of glycerol and pH between 6 and 7. The antimicrobial activity test showed
that the supernatants did not show activity against the tested strains. Remarkably high
antioxidant activity was observed for both supernatants and the control (MRS), indicating the
possibility of the presence of some interference in the culture medium. In addition, inhibitory
activity for amyloglucosidase (20.7% to 23.9%) was observed. The presence of lipolytic
activity was verified in the supernatants (16,12 and 19,00 U/mL). It was also verified that the
variables peptone concentration, lactose, and pH positively influenced the production of
bacteriocins by L. paracasei. Therefore, L. paracasei can be suggested as a viable source of
metabolites with antidiabetic, antimicrobial (bacteriocins), bioemulsifying, and lipolytic
activities

COMMITTEE MEMBERS:
Presidente - 3652554 - FRANCISCO CANINDE DE SOUSA JUNIOR
Externa à Instituição - CATHERINE TEIXEIRA DE CARVALHO - UFPB
Externa à Instituição - NATHALIA KELLY DE ARAUJO - IFRO
Notícia cadastrada em: 07/06/2023 14:47
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