Search Results

You are looking at 1 - 3 of 3 items for

  • Author: Milan Certik x
Clear All Modify Search
Open access

Jana Tkáčová, Katarína Furdíková, Tatiana Klempová, Katarína Ďurčanská and Milan Čertík

Abstract

Carotenoids represent large group of various natural pigments ensuring typical coloration of plants, microorganisms and several animals. It was confirmed by many studies, that consuming these biological active compounds has positive impact for human life. Therefore, they are applied in different industrial fields, such as pharmacy, cosmetic, food, and feed industry. Due to high demand for carotenoids we would like to discover new microorganisms overproducing carotenoids. We focused on yeasts of genus Rhodotorula sp. (forty isolates), that we screened according to growth and carotenoid production on Petri dishes and production media. After cultivation on Petri dishes we selected five strains (denoted as KF-4, KF-6, KF-24, KF-31, KF-104) with interesting pigment production and quick growth. The secondary screening on production media identified KF-104 as the best producer of carotenoid pigments with massive pigment accumulation (1.15 mg/g DCW) and yield (9.69 mg/L). The main carotenoid of KF-104 isolate was β-carotene (35.4 %) with the accumulation of 408.7 μg/g DCW and the yield of 3.4 mg/L. The rest were torularhodin, torulene and γ-carotene (62.7–79.0 %). Production of torularhodin in the cells was low (0.4 to 1.4 mg/L) as was its accumulation in cells (31.2–121.0 μg/g DCW). We continue the experimental analyses of these isolates in order understand differences in the content of individual pigments.

Open access

Martin Vanek, Filip Mravec, Martin Szotkowski, Dana Byrtusova, Andrea Haronikova, Milan Certik, Volha Shapaval and Ivana Marova

Abstract

Red yeast Cystofilobasidium capitatum autofluorescence was studied by means of confocal laser scanning microscopy (CLSM) to reveal distribution of carotenoids inside the cells. Yeasts were cultivated in 2L fermentor on glucose medium at permanent light exposure and aeration. Samples were collected at different times for CLSM, gravimetric determination of biomass and HPLC determination of pigments. To compare FLIM (Fluorescence Lifetime Imaging Microscopy) images and coupled data (obtained by CLSM) with model systems, FLIM analysis was performed on micelles of SDS:ergosterol and SDS:coenzyme Q with different content of ergosterol and coenzyme Q, respectively, and with constant addition of beta-carotene. Liposomes lecithin:ergosterol:beta-carotene were investigated too. Two different intracellular forms of carotenoids were observed during most of cultivations, with third form appeared at the beginning of stationary phase. Observed behavior is probably due to formation of some kind of carotenoid protective system in membranes of different compartments of yeast cell, especially cytoplasmic membrane.

Open access

Ivana Marova, Martin Szotkowski, Martin Vanek, Marek Rapta, Dana Byrtusova, Nadzeya Mikheichyk, Andrea Haronikova, Milan Certik and Volha Shapaval

Abstract

Red yeast strains are ubiquitous microorganisms which accumulate substantial amounts of lipids and lipid-soluble metabolites. Red yeasts utilize many waste substrates of different origin. In this work red yeasts strains (Rhodotorula, Sporobolomyces, Cystofilobasidium) were used for screening of growth and metabolic activity. As a carbon source waste animal fat and its hydrolysis products were used. Hydrolysis of animal fat was tested in alkaline as well as acidic conditions. As the substrate glucose (control), glycerol, crude animal fat, acid fat hydrolyzate and hydrolysate: glucose 1:2 were used. Screening of growth and metabolic activity of red yeasts was performed by flow cytometry. Extracellular lipase production was monitored as adaptation mechanism. Carotenoids, ergosterol and ubiquinone were quantified by HPLC/PDA/MS/ESI and the biomass was evaluated gravimetrically. All tested strains utilized fat hydrolysate and produced red coloured biomass. Cultivation in media containing non-hydrolysed fat led to strain specific induction of extracellular lipase. Amount of lipid metabolites produced by individual strains was depended on glycerol content in medium. The highest increase of lipase production was observed in Cystofilobasidium macerans and Sporobolomyces shibatanus. Valorisation of animal fat can lead to production of unsaturated fatty acids, single cell oils, carotenoid pigments, sterols and enriched red yeast biomass.