Isolation and characterization of psychrophilic yeasts producing cold-adapted pectinolytic enzymes

Abstract

Aims: The present study was conducted to screen for psychrophilic yeasts that are able to degrade pectin compounds at low temperature, and to examine the cold‐active pectinolytic enzymes produced by the isolated psychrophilic yeasts. Methods and Results: Psychrophilic yeasts, which grow on pectin as a sole carbon source, pectinolytic–psychrophilic yeast (PPY) strains PPY‐3, 4, 5 and 6, were isolated from soil from Abashiri (Hokkaido, Japan). The sequences of 28S rDNA D1/D2 of strains PPY‐3 and 4 indicated a taxonomic affiliation to Cryptococcus cylindricus and Mrakia frigida, respectively, strains PPY‐5 and 6 belonged to Cystofilobasidium capitatum. The isolated strains were able to grow on pectin at below 5°C, and showed the activities of several cold‐active pectinolytic enzymes. Conclusion: The findings of this study indicate the possibility that the isolated strains produce novel pectinolytic enzymes that are able to degrade pectin compounds at low temperature. Significance and Impact of the Study: It is possible that the cold‐active pectinolytic enzymes from the isolated strains can be applied to the food industry, e.g. the clarification of fruit juice below 5°C.

Cold-Active Polygalacturonase from Psychrophilic-Basidiomycetous Yeast Cystofilobasidium capitatum Strain PPY-1

“…4,6) In previous studies, we isolated several Pectinolytic and Psychrophilic Yeast (PPY) strains from forest soil from Abashiri, Hokkaido, Japan. 7,8) Among these strains, Cystofilobasidium capitatum strain PPY-1 grew on pectic compounds at temperatures below 5 C, and the extracellular fraction of strain PPY-1 exhibited high PG activity at 5 C. These findings might indicate that strain PPY-1 produces a cold-active PG able to degrade pectic compounds at low temperatures. In this study, we attempted to purify and characterize this cold-active PG from strain PPY-1.…”

“…So far, some PPY strains, which can grow on pectin at 5 C, have been isolated and characterized by our group and by Birgisson et al 7,8,14) In this study, we purified and characterized PG from C. capitatum strain PPY-1, the most dominant PPY species. 7,8,14) The enzymatic property of most interest in this study was the temperature dependency of PG. Although the optimal temperature was 45 C, PG exhibited high residual activity and a low K m value at 0 C. This suggests that PG from strain PPY-1 is a cold-active enzyme.…”

Mrakiella cryoconiti gen. nov., sp. nov., a psychrophilic, anamorphic, basidiomycetous yeast from alpine and arctic habitats

“…Members of this genus have been isolated from numerous low-temperature environments in various regions, such as forest substrates in European Russia, glacier-preserved fossil lichens in Greenland, Antarctic soil or snow, glacial meltwater rivers in Patagonia, Argentina, and alpine Italian subglacial sediments, ice and meltwater, but also from frozen fish in Japan and frozen yoghurt in Brazil (Fell & Statzell-Tallman, 1998;Moreira et al, 2001;Bab'eva et al, 2002;Xin & Zhou, 2007;Turchetti et al, 2008). Some strains related to the species Mrakia frigida produce cold-active pectinolytic enzymes (Barnett et al, 2000;Nakagawa et al, 2004). These enzymes could be useful for a wide range of applications, such as the food industry for juice clarification below 5 u C or low-temperature pre-treatment of wastewater containing pectic substances.…”

Mrakia psychrophila sp. nov., a new species isolated from Antarctic soil

“…nov. from Terre Adelie, Antarctica, which produced a cold-active xylanase. Nakagawa et al(2004) isolated some psychrophilic yeast strains of Cryptococcus cylindricus and Mrakia frigida from soil of Abashiri. The isolated strains can grow on pectin as the only carbon at below 5 °C, and showed the activities of several cold-active pectinolytic enzymes.…”