Physico-chemical characterization of exomannan from Rhodotorula acheniorum MC

Abstract

The batch fermentation of Rhodotorula acheniorum MC on a culture medium containing 5% sucrose, mineral salts and yeast extract at 26°C for 96 h, with aeration at 0.75 v/v/m and agitation at 500 rev min )1 resulted in the synthesis of an exopolysaccharide (6.2 g l )1 ) which formed two fractions upon precipitation. The fractions were purified to a carbohydrate content of 98.2% for fraction I and 87.3% for fraction II. Mannose was the main monosaccharide component in a 92.8% concentration in fraction I and a 90.6% concentration in Fraction II. The exopolysaccharide was thus a mannan. The gel chromatograms confirmed the chemical composition of both fractions. The molecular weight of mannan I was 310 kD, whereas that of mannan II was 249 kD. The mannan I intrinsic viscosity [g] ¼ 6.23 dl g )1 was higher than that of mannan II [g] ¼ 2.73 dl g )1 . The water-binding capacity of the mannan samples was established within the 1.2-3.5 g g )1 range. The multiplicative model [g] ¼ 387.22. D À0:1913 r . T )1.095 . C 1.814 describing the effect of the velocity gradient D r , the exomannan concentration C and the temperature T on the dynamic viscosity values g of polymer solutions was obtained.

General factors important for the formation of structured biofilm-like yeast colonies

“…It was shown, for example, that they can comprise up to approximately 80% of the extracellular polymeric material produced by C. albicans (McCourtie and Douglas, 1985). Polysaccharides possess a high water binding capacity as was shown for the extracellular mannans of Rhodotorula acheniorum, which were able to retain such an amount of water to multiply its own mass by a factor of 3.5 (Pavlova et al, 2005). ECM thus can considerably contribute to the retention of extracellular fluid in fluffy S. cerevisiae colonies.…”

Exopolysaccharides from yeast: insight into optimal conditions for biosynthesis, chemical composition and functional properties – review

“…Sporobolomyces salmonicolor AL 1 (Pavlova et al, 2004) and Rhodotorula glutinis (Cho et al, 2001) were cultured at the same temperature. Cryptococcus fl avus A 51 was incubated at 24°C (Pavlova et al, 2009), while Rhodotorula acheniorum MC under conditions of the bioreactor at a temperature of 26°C (Pavlova et al, 2005). In the case of the latter strain, the largest biomass yield was obtained at a lower temperature of 20°C.…”

“…Fraction I was characterized by a compact, fi brous structure, and its molecular weight was 310 kDa, while fraction II was separated in the form of soft and loose mass (249 kDa). Carbohydrates content in the purifi ed fractions was 98.2% for fraction I, and 87.3% for fraction II (Pavlova et al, 2005). The yeasts that produce heterogeneous polymers in the same culture also include Candida laurentii CCY 17-3-16 (Breierová et al, 2005) and Candida laurentii AL 62 (Rusinova-Videva et al, 2011).…”

Polissacarídeos de parede celular fúngica: purificação e caracterização

“…Há uma forte tendência em se explorar comercialmente a biomassa fúngica para isolamento de seus componentes celulares e consequentemente de seus principais constituintes, tais como enzimas (invertases, glucosidades), nucleotídeos, proteínas (manoproteínas) e principalmente polissacarídeos (glucanas, mananas, galactanas), além de lipídeos, como fosfolipídeos e ergosterol, pois estas substâncias apresentam propriedades específicas de interesse biotecnológico e, conseqüentemente, de grande valor agregado (BELEM;LEE, 1998;BEROVIČ et al, 2003;CAMERON;COOPER;NEUFELD, 1988;KOLLÁR;STURDIK;SAJBIDOR, 1992;PAVLOVA, PANCHEV;HRISTOZOVA, 2005 A biomassa excedente da produção industrial de antibióticos por Penicillium chrysogenum, além de ser aproveitada para ração para gado e ou no preparo de fertilizantes (MUZZARELLI et al, 2000), também vem se mostrando uma fonte viável de moléculas importantes, como os polissacarídeos do tipo glucanas , aplicados na área medicinal devido a suas atividades antitumorais e imunomoduladoras.…”