Synthesis and Characterization of an Exopolysaccharide by Antarctic Yeast Strain Cryptococcus laurentii AL100

Abstract

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.

Cryptococcus laurentii Extracellular Biopolymer Production for Application in Wound Management

“…Besides, a range of neutral polysaccharides and polysaccharide-protein complexes is reported in C. laurentii EPS: glucan, containing 1→ 3, 1→4, 1→2, and (or) 1→6 linkages [6], and heteropolysaccharide composed of mannose, galactose, and xylose [7], glucomannan-protein complex [8], and galactoglucoxylomannan protein [9]. In the latest studies, C. laurentii heteropolysaccharide composed of arabinose, mannose, glucose, galactose, and rhamnose is reported [10].…”

Biosynthesis and Characterization of Exopolysaccharides and Lipids from Antarctic Yeasts

“…in our previous study the monosaccharide composition of the exopolysaccharide was reported (11,15). Mannose and glucose were present in the composition of all biopolymers.…”

“…the progress in the study of Antarctic microorganisms involves creation of culture collections, investigation of their specific metabolism of adaptation to environmental conditions, biodiversity, taxonomic determination, biochemical characterization and synthesis of biologically active compounds from strains with a potential for enzyme, polysaccharide, lipid, carotenoid, and bioremediation agent synthesis, etc. (3,5,6,9,12,15,16,17,20,22,24).…”

Prevalence of Decreased Susceptibility of Cryptococcus spp. Isolates to Fluconazole in Urban Sources of Presidente Prudente

“…These yeasts are found in air, water, wood, soil, pigeon droppings, and in foods such as fruit, pork and beans [18]. C. laurentii is distinguished by its adaptive ability to live in various environments, as it is isolated from areas with tropical climates as well as regions with below zero temperatures, such as Antartica [22]. Ref.…”