INVESTIGADORES
DELGADO Osvaldo Daniel
artículos
Título:
Cold adapted yeasts as producers of cold adapted polygalacturonase.
Autor/es:
BIRGISSON H; DELGADO O; HATTI-KAUL R; MATTIASSON B
Revista:
Extremophiles
Editorial:
Springer
Referencias:
Lugar: Japon; Año: 2003 vol. 7 p. 185 - 193
Resumen:
Eight cold-adapted, polygalacturonase-producing yeasts belonging to
four species were isolated from frozen environmental samples in
Iceland. They were identified as Cystofilobasidium lari-marini, Cystofilobasidium capitatum, Cryptococcus macerans and Cryptococcus aquaticus
species by sequence analysis of rDNA regions. Growth behavior of the
isolates was investigated. All strains could grow at 2°C. Addition of
glucose to pectin-containing culture medium had a repressive effect on
enzyme production except for C. aquaticus, which showed increased polygalacturonase activity. Optimal temperature for enzyme production for the Cystofilobasidium strains was 14°C, while that for the Cryptococcus strains was lower. Among the isolates, C. lari-marini
S3B produced highest levels of enzyme activity at pH 3.2. Preliminary
characterization of the polygalacturonases in the culture supernatant
showed the enzyme from Cystofilobasidium strains to be optimally active at 40°C and pH 5, and that from the Cryptococcus strains at 50°C and pH 4. The polygalacturonase from C. macerans
started to lose activity after 1 h of incubation at 40°C, while that
from the other strains had already lost activity at 30°C. All the
strains except C. aquaticus produced isoenzymes of polyglacturonase. In addition to polygalacturonase, the Cystofilobasidium strains produced pectin lyase, C. aquaticus pectin esterase, and C. macerans pectin lyase, pectate lyase and pectin esterase.