Naslov (eng)

FERMENTATION OF POPLAR BUD EXTRACTS USING LACTIC ACID BACTERIA

Autor

Žilović, Jana
Đukić-Vuković, Aleksandra
Bogdanović, Mihajlo
Grbić, Jovana
Tadić, Vanja
Žugić, Ana

Opis (eng)

Poplar bud extracts of various poplar species are implemented in traditional medicine for wound healing due to their astringent and antiseptic properties. In recent years, poplar trees have been cultivated for the purpose of wood biomass production, whereas side shoots and buds are discarded and used as fuel. On the other hand, lactic acid bacteria (LAB) are widely used in producing fermented and functional food products, for their probiotic properties and ability to produce enzymes, acids, and other bioactive compounds. The aim of this study was to examine the chemical composition of prepared poplar bud extracts before lactic acid fermentation, as well as the effect the extracts had on the viability of LAB cells. Due to abundance and high availability, buds of cultivated poplar species Populus x euramericana (Dode) Guinier I-214 were utilized in this research. Maceration and ultrasonic extraction were the selected methods for extracting poplar buds, while 50% (v/v) ethanol was used as a solvent. The obtained liquid extracts were evaporated using a rotary vacuum evaporator. The chemical composition of poplar bud extracts was examined by high-performance liquid chromatography (HPLC), while their antimicrobial activity was assessed using the agar well diffusion method. Fermentation of prepared extracts was carried out using Lacticaseibacillus rhamnosus ATCC 7469, Ligilactobacillus salivarius ATCC11741, and Lactiplantibacillus plantarum 299v as model microorganisms. The potential antimicrobial activity of extracts was assessed against Escherichia coli, Bacillus cereus, Staphylococcus aureus and Candida albicans. To analyze the effect of extract concentration on the fermentation process and cell viability, two different concentrations of extracts were prepared, by dissolving the extracts in 3% DMSO and sterile water. After 24 hours of fermentation, the number of viable LAB cells and the pH of the extracts were measured. The results of the HPLC analysis demonstrated that the poplar bud extract obtained by ultrasonic extraction (UE) had an overall higher concentration of polyphenolic compounds than the macerate (M). Notably, UE mainly contained phenolic acids (caffeic and rosmaric acid), while M was predominantly comprised of flavonoids (pinocembrin, chrysin, and pinostrobin). The number of viable LAB cells after extract fermentation showed that prepared poplar bud extracts were not suitable for the cultivation and survival of examined bacterial species. Consequently, only a certain number of L. plantarum cells were viable after fermentation in the UE extract, which contained 8 mg/ml of dry extract. The agar well diffusion test revealed that the prepared extracts exhibited antimicrobial activity towards Staphylococcus aureus and Bacillus cereus, but did not show inhibitory effects against Escherichia coli and Candida albicans. Furthermore, the decrease in the pH value of the extracts after 24 hours of fermentation indicated biotransformations by the examined LAB species. In conclusion, in order to better understand the transformations that occur during fermentation, it is important to analyze the chemical composition of the extracts after fermentation. Additionally, alternative extraction methods and solvents should be explored to obtain extracts with improved solubility.

Jezik

engleski

Datum

2025

Licenca

© All rights reserved

Predmet

poplar, extraction, polyphenols, microbial transformation, lactic acid bacteria

Deo kolekcije (1)

o:2594

Radovi nastavnika i saradnika Instituta za proučavanje lekovitog bilja "Dr Josif Pančić"