Background: The exopolysaccharides (EPS) produced by yeast exhibit physico-chemical and rheological
properties, which are useful in the production of food and in the cosmetic and pharmaceutical industries as
well. The effect was investigated of selected carbon sources on the biosynthesis of EPS by
Candida famata
and
Candida guilliermondii
strains originally isolated from kefirs.
Results: The biomass yields were dependent on carbon source (sucrose, maltose, lactose, glycerol, sorbitol) and
ranged from 4.13 to 7.15 g/L. The highest biomass yield was reported for
C. guilliermondii after cultivation on
maltose. The maximum specific productivity of EPS during cultivation on maltose was 0.505 and 0.321 for
C. guilliermondii and
C. famata, respectively. The highest EPS yield was found for
C. guilliermondii strain. The EPS
produced under these conditions contained 65.4% and 61.5% carbohydrates, respectively. The specific growth rate
(μ) of
C. famata in medium containing EPS as a sole carbon source was 0.0068 h
-1 and 0.0138 h
-1 for
C. guilliermondii strain.
Conclusions: Themost preferred carbon source in the synthesis of EPS for both
Candida strains was maltose, wherein
C. guilliermondii strain showed the higher yield of EPS biosynthesis. The carbon source affected the chemical
composition of the resulting EPS and the contribution of carbohydrate in the precipitated preparation of polymers
was higher during supplementation of maltose as compared to sucrose. It was also found that the EPS can be a
source of carbon for the producing strains.
