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Cold-adapted yeasts as producers of cold-active polygalacturonases
Hákon Birgisson1, Osvaldo Delgado, Leticia García Arroyo
1Department of Biotechnology, Center for Chemistry and Chemical Engineering, Lund University, Box 124, 22100 Lund, Sweden.
Extremophiles : Life Under Extreme Conditions
|May 28, 2003
Summary
Eight cold-adapted yeasts isolated from Iceland produce polygalacturonase enzymes. These yeasts exhibit varying enzyme activity and stability, with potential applications in biotechnology.
Area of Science:
- Microbiology
- Enzymology
- Biotechnology
Background:
- Cold-adapted yeasts are valuable sources of enzymes for industrial applications.
- Polygalacturonases are enzymes that degrade pectin, a major component of plant cell walls.
Purpose of the Study:
- To isolate and identify cold-adapted, polygalacturonase-producing yeasts from Icelandic environments.
- To investigate the growth characteristics and polygalacturonase production of these yeast isolates.
- To characterize the enzymatic properties of the produced polygalacturonases.
Main Methods:
- Isolation of yeasts from frozen environmental samples in Iceland.
- Identification using rDNA sequence analysis.
- Investigation of growth behavior at low temperatures.
- Enzyme production optimization (temperature, pH).
- Preliminary characterization of polygalacturonase activity and stability.
Main Results:
- Eight yeast strains from four species (Cystofilobasidium lari-marini, C. capitatum, Cryptococcus macerans, C. aquaticus) were identified.
- All isolates grew at 2°C; glucose repressed polygalacturonase production in most strains.
- Optimal enzyme production temperatures varied between genera (14°C for Cystofilobasidium, lower for Cryptococcus).
- Polygalacturonases showed different optimal activity (40°C/pH 5 for Cystofilobasidium, 50°C/pH 4 for Cryptococcus) and stability.
- Additional pectinolytic enzymes were produced by some strains.
Conclusions:
- Cold-adapted yeasts from Iceland are a promising source of diverse polygalacturonase enzymes.
- Enzyme characteristics vary significantly, suggesting strain-specific applications.
- Further research into these enzymes could lead to novel biotechnological uses.