Vpliv fermentacije na vsebnost karotenoidov v ekstraktih mikroalg vrst Arthrospira platensis in Chlorella vulgaris

Vidović, Lana (author), Poklar Ulrih, Nataša (mentor), Skrt, Mihaela (comentor)

V raziskavi smo določali profil karotenoidov v cianobakteriji Arthrospira platensis in mikroalgi Chlorella vulgaris ter vpliv mlečnokislinske fermentacije na prisotnost karotenoidov in fenolnih spojin. Pripravili smo ekstrakte past biomas A. platensis in C. vulgaris v dveh različnih topilih (100-% aceton, kloroform : metanol = 1 : 2). V ekstraktih smo karotenoide ovrednotili s spektrofotometrično metodo in s tankoplastno kromatografijo. V raziskavi smo ugotovili, da se vsebnost karotenoidov in ustreznost topil, ki sta se uporabljali pri A. platensis in C. vulgaris, razlikujeta, saj je aceton dal boljše rezultate za vzorce A. platensis in mešanica kloroform : metanol za vzorce C. vulgaris. Iz kontrolne biomase A. platensis smo s 100-% acetonom ekstrahirali 4,37 ± 0,16 (mg/g suhe biomase) karotenoidov in iz fermentirane 4,37 ± 0,07 (mg/g suhe biomase) karotenoidov. Z mešanico kloroform : metanol smo iz kontrolne biomase A. platensis ekstrahirali 25,9 % manj karotenoidov in iz fermentirane biomase 13,3 % manj karotenoidov. Iz kontrolne in fermentirane biomase C. vulgaris smo s 100-% acetonom ekstrahirali skoraj 10-krat manj skupnih karotenoidov, in sicer 0,45 ± 0,01 (mg/g suhe biomase) in 0,52 ± 0,02 (mg/g suhe biomase). Tudi z mešanico kloroform : metanol smo ekstrahirali manj karotenoidov, tako iz kontrolne biomase C. vulgaris kot fermentirane, in sicer 2,27 ± 0,12 (mg/g suhe biomase) in 1,39 ± 0,02 (mg/g suhe biomase). S tankoplastno kromatografijo smo ločili mešanico pigmentov v ekstraktih iz past kontrolnih in fermentiranih biomas. Pri A. platensis smo uspeli ločiti 10-16 komponent več z uporabo mešanice 1 kot z uporabo drugih mešanic, medtem ko smo pri C. vulgaris uspeli ločiti 4-13 komponent več z uporabo mešanice 3 kot z uporabo preostalih mešanic topil. S Folin-Ciocalteujevo metodo smo določali tudi vsebnost fenolnih spojin. Fenolne spojine predstavljajo od najmanj 0,02 % do največ 0,44 % biomase. Ugotovili smo, da je koncentracija skupnih fenolnih spojin višja v fermentiranih vzorcih kot v kontrolnih ter da A. platensis na splošno vsebuje več karotenoidov in skupnih fenolnih spojin (SFS) kot C. vulgaris.

• Language: Slovenian
• Keywords: prehrana, mikroalge, cianobakterije, Arthrospira platensis, Chlorella vulgaris, fenolne spojine, bioaktivne spojine, antioksidanti, karotenoidi, prebava, absorpcija, metabolizem, ekstrakcija, tankoplastna kromatografija, spektrofotometrija
• Work type: Master's thesis/paper
• Typology: 2.09 - Master's Thesis
• Organization: BF - Biotechnical Faculty
• Place of publishing: Ljubljana
• Publisher: [L. Vidović]
• Year: 2021
• PID: 20.500.12556/RUL-131709
• UDC: 577.161:582.2/.3:66.061
• COBISS.SI-ID: 78658307
• Publication date in RUL: 01.10.2021

Secondary language

• Language: English
• Title: Effect of fermentation on the carotenoids content in the extracts of microalgae species of Arthrospira platensis and Chlorella vulgaris

Abstract

In this research, we determined profiles of carotenoids in cyanobacteria A. platensis and microalgae C. vulgaris, the effect of lactic acid fermentation on present carotenoids, and also the presence of phenolic compounds. Biomass paste extracts of A. platensis and C. vulgaris were prepared in two different solvents (100 % acetone, chloroform : methanol = 1 : 2) so that we can compare the results and see which solvent is giving better results. After extraction, we tried to determine carotenoids by various methods, such as spectrophotometry and thin-layer chromatography. In addition to carotenoids, the presence of phenolic compounds was also determined using the Folin-Ciocalteu method. In this study, we found that the carotenoid content and solubility of the solvents used differed between A. platensis and C. vulgaris, as one solvent gave better results for A. platensis samples and the other solvent for C. vulgaris samples. 4.37 ± 0.16 (mg/g d. m.) was extracted from unfermented biomass of A. platensis in 100 % acetone and 4.37 ± 0.07 (mg/g d. m.) from fermented biomass. 3.24 ± 0.53 (mg/g d. m.) was extracted from unfermented biomass of A. platensis in chloroform : methanol solvent mixture and 3.79 ± 0.25 (mg/g d. m.) of fermented biomass. When it comes to A. platensis we extracted 14–22 % more carotenoids with 100 % acetone than with chloroform : methanol solvent mixture. 0.45 ± 0.01 (mg/g d. m.) was extracted from unfermented biomass of C. vulgaris in 100 % acetone and 0.52 ± 0.02 (mg/g d. m.) from unfermented biomass. 2.27 ± 0.12 (mg/g d. m.) was extracted from unfermented biomass of C. vulgaris in chloroform : methanol solvent mixture and 1.39 ± 0.02 (mg/g d. m.) of fermented biomass. When it comes to C. vulgaris we extracted 2–4 % more carotenoids with chloroform : methanol solvent mixture than with 100 % acetone. The same was observed in thin layer chromatography by comparing the suitability of four solvent mixtures. In A. platensis a non-polar solvent mixture 1 separated 10-16 more components compared to any of the other mixtures used and in C. vulgaris a polar solvent mixture 3 separated 4-13 more components compared to other solvent mixtures. We also used Folin-Ciocalteu method to determine the content of phenolic compounds. Phenolic compounds represent from at least 0.2 % to the maximum of 0.44 % of biomass. Finally, we concluded that the concentration of total phenolic compounds and carotenoids is generally higher in fermented samples than in unfermented samples and that A. platensis generally contains more carotenoids and total phenolic compounds (TPC) than C. vulgaris.

• Keywords: nutrition, microalgae, cianobacteria, Arthrospira platensis, Chlorella vulgaris, phenolic compounds, bioactive compounds, antioxidants, carotenoids, digestion, absorption, metabolism, extraction, thin layer chromatography, spectrophotometry