Banca de QUALIFICAÇÃO: NAIANY SILVA DE MEDEIROS

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : NAIANY SILVA DE MEDEIROS
DATE: 03/04/2023
TIME: 14:00
LOCAL: Link de acesso para videoconferência: https://meet.google.com/zvt-ieft-zyx
TITLE:

Evaluation of the biotechnological potential of Lacticaseibacillus paracasei for the production of bioemulsifiers, bacteriocins and lipase

KEY WORDS:

Lacticaseibacillus paracasei; bioemulsifier; bacteriocin; lipase.

PAGES: 77
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, was observed inhibitory activity for amyloglucosidase (20.7% to 23.9%). 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:
Externa à Instituição - CATHERINE TEIXEIRA DE CARVALHO - UFPB
Presidente - 2378605 - CRISTIANE FERNANDES DE ASSIS
Externa à Instituição - NATHALIA KELLY DE ARAUJO - IFRO