title: Long term storage of Pleurotus ostreatus and Trametes versicolor isolates using different cryopreservation techniques and its impact on laccase activity.
abstract: The strain Pleurotus ostreatus Florida f6, its 45 basidiospore-derived isolates (both monokaryons and dikaryons prepared in our laboratory), Trametes versicolor strain CCBAS 614 and 22 other T. versicolor isolates obtained from the sporocarps collected in distant localities were successfully preserved for 12 y using perlite and straw cryopreservation protocols. All tested isolates survived a 12-year storage in liquid nitrogen (LN) and their laccase production and Poly B411 decolorization capacity was preserved. Also mycelium extension rate and the types of colony appearance of individual isolates remained unchanged. Different cryopreservation techniques were also tested for the short time (24 h) and the long time (6 m) storage of the culture liquid with extracellular laccase produced by T. versicolor strain CCBAS 614. The results showed that 10 % glycerol was the most suitable cryopreservant. The absence of the cryopreservant did not cause high loss of laccase activity in the samples; the presence of DMSO (5 or 10 %) in LN-stored samples caused mostly a decrease of laccase activity. For the preservation of laccase activity in the liquid culture the storage in the freezer at -80 °C is more convenient than the storage in liquid nitrogen.
authors.affiliation: Institute of Microbiology, Academy of Sciences of the Czech Republic (ASCR), v.v.i., Vídeňská 1083, 142 20 Prague 4, Czech Republic. Electronic address: eichler@biomed.cas.cz.
authors.forename: Ivana
authors.initials: I
authors.lastname: Eichlerová
authors.affiliation: Institute of Microbiology, Academy of Sciences of the Czech Republic (ASCR), v.v.i., Vídeňská 1083, 142 20 Prague 4, Czech Republic.
authors.forename: Ladislav
authors.initials: L
authors.lastname: Homolka
authors.affiliation: Faculty of Forestry and Wood Technology, Mendel University in Brno, Zemědělská 3, 61300 Brno, Czech Republic.
authors.forename: Michal
authors.initials: M
authors.lastname: Tomšovský
authors.affiliation: Institute of Microbiology, Academy of Sciences of the Czech Republic (ASCR), v.v.i., Vídeňská 1083, 142 20 Prague 4, Czech Republic.
authors.forename: Ludmila
authors.initials: L
authors.lastname: Lisá
mesh_terms: D015925:Cryopreservation / Q000379:methods*; D005656:Fungal Proteins / Q000032:analysis* / Q000378:metabolism; D042845:Laccase / Q000032:analysis / Q000378:metabolism*; D050296:Microbial Viability; D010944:Plants / Q000382:microbiology*; D020076:Pleurotus / Q000737:chemistry* / Q000201:enzymology* / Q000254:growth & development / Q000302:isolation & purification; D055454:Trametes / Q000737:chemistry* / Q000201:enzymology* / Q000254:growth & development / Q000302:isolation & purification
chemical_list: D005656:Fungal Proteins; D042845:Laccase
keywords: Basidiomycetes; Cryopreservant; Liquid nitrogen; Perlite protocol; Straw protocol