Synthesis and characterization of an exopolysaccharide by antarctic yeast strain Cryptococcus laurentii AL₁₀₀.
An exopolysaccharide-producing Antarctic yeast strain was selected and identified as Cryptococcus laurentii AL₁₀₀. The physiological properties of the strain and its ability to utilize and biotransform different carbon sources (pentoses, hexoses, and oligosaccharides) into exopolysaccharide and biomass were investigated. Sucrose was chosen as a suitable and accessible carbon source. The biosynthetic capacity of the strain was studied in its dynamics at different sucrose concentrations (20, 30, 40, and 50 g/L) and temperatures (22 and 24 °C). The maximum biopolymer quantity of 6.4 g/L was obtained at 40 g/L of sucrose, 22 °C temperature and 96-h fermentation duration. The newly synthesized microbial carbohydrate was a heteropolysaccharide having the following monosaccharide composition: arabinose, 61.1%; mannose, 15.0%; glucose, 12.0%; galactose, 5.9%; and rhamnose, 2.8%. It was characterized by polydispersity of the polymer molecule, 60% of it having molecular mass of 4200 Da. The exopolysaccharide demonstrated good emulsifying and stabilizing properties with regard to oil/water emulsions and a pronounced synergistic effect with other hydrocolloids such as xanthan gum, guar gum, and alginate.
Laboratory of Applied Biotechnologies, Institute of Microbiology, Bulgarian Academy of Sciences, 139 Ruski Blvd, Plovdiv 4000, Bulgaria.
Kostantsa
K
Pavlova
Snezhana
S
Rusinova-Videva
Margarita
M
Kuncheva
Maria
M
Kratchanova
Mariana
M
Gocheva
Stela
S
Dimitrova
D002240:Carbohydrate Sequence; D003454:Cryptococcus / Q000737:chemistry / Q000378:metabolism*; D005110:Extracellular Space / Q000737:chemistry / Q000378:metabolism*; D008969:Molecular Sequence Data; D011134:Polysaccharides / Q000096:biosynthesis* / Q000737:chemistry*; D013395:Sucrose / Q000378:metabolism
D011134:Polysaccharides; D013395:Sucrose