Production and Chemical Characterization of Exopolysaccharides by Antarctic Yeasts Vishniacozyma victoriae and Tremellomycetes sp.

The study aimed to investigate exopolysaccharides (EPSs) produced by two Antarctic yeasts isolated from Livingston Island. The species were identified as Vishniacozyma victoriae (V) and Tremellomycetes sp. (T) based on a molecular genetic analysis of ITS1-5.8S-ITS4 regions of the 18S rRNA gene. The...

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Bibliographic Details
Published in:Applied Sciences
Main Authors: Snezhana Rusinova-Videva, Manol Ognyanov, Yordan Georgiev, Margarita Kambourova, Aleksandar Adamov, Vasilena Krasteva
Format: Article in Journal/Newspaper
Language:English
Published: MDPI AG 2022
Subjects:
Antarctic yeasts
polysaccharides
biotechnology
chromatography
spectroscopy
Technology
T
Engineering (General). Civil engineering (General)
TA1-2040
Biology (General)
QH301-705.5
Physics
QC1-999
Chemistry
QD1-999
Antarctic
Livingston Island
Antarc*
Online Access:https://doi.org/10.3390/app12041805
https://doaj.org/article/1114ac0ded154ab4ad4cd697252ced0c
Description
Summary:The study aimed to investigate exopolysaccharides (EPSs) produced by two Antarctic yeasts isolated from Livingston Island. The species were identified as Vishniacozyma victoriae (V) and Tremellomycetes sp. (T) based on a molecular genetic analysis of ITS1-5.8S-ITS4 regions of the 18S rRNA gene. The EPS production was investigated under stress conditions in culture flasks and a bioreactor. Different chromatographic (HPLC-RID, HPSEC-RID) and spectral (FT-IR) analyses were employed to characterize EPSs. Tremellomycetes sp. accumulated 7 g/L biomass and 4.5 g/L EPS after 120 h of cultivation. The total carbohydrate content of V-EPS and T-EPS was 75.4% and 79.0%, respectively. The EPSs mainly consisted of mannose (30–32%), which was followed by glucose, xylose, galactose, and small amounts of uronic acids (6.3–7.0%). EPSs had appreciable amounts of proteins (11–12%). The FT-IR spectra contained absorption bands typical for hetero-mannans and β -glucans (797–1033 cm −1 ). EPSs were heterogeneous with a broad molecular weight distribution range (47 × 10 4 –68 × 10 4 g/mol). In conclusion, both yeasts synthesized high-molecular-weight heteromannans, and Tremellomycetes sp. stood out as being a better producer than V. victoriae . The current study also formed a basis for a better assessment of the potential for practical application of EPSs and yeasts in biochemical engineering and biotechnology.

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