ISOLATION AND CHARACTERISATION OF TWO THERMOTOLERANT KLUYVEROMYCES YEAST STRAINS
Anna Kujumdzieva1*, Trajana Nedeva1, Maria Morfova1 and Valentin Savov2
1The Sofia University, Biological Faculty, Department of
General and Industrial Microbiology,
8 "Dragan Tsankov" st., 1421 Sofia, Bulgaria;
2The Sofia University, Biological Faculty, Department of
Engineering Biology,
8 "Dragan Tsankov" st., 1421 Sofia, Bulgaria
Summary
Two new thermotolerant
lactose consuming yeast strains, producers of thermostabile superoxide
dismutase (SOD) (EC: 1.15.1.1.) were isolated and taxonomically identified
as Kluyveromyces marxianus var. lactis T1 and Kluyveromyces marxianus var.
bulgaricus T3. The influence of carbon source and growth temperature on
the specific growth rate and SOD biosynthesis was also studied. Both strains
grew well on lactose and/or lactose containing feedstocks and those substrates
could be used for the production of SOD enzyme with high activity. Temperature
of 40oC was proved to be suitable for cultivation of both strains
with respect of SOD biosynthesis. Assay for thermostability of SOD enzyme
of T1 and T3 strains cultivated on lactose shows that it is a thermostable
one.
The newly isolated and
identified strains can be used as producers of thermostable SOD when grown
on lactose and lactose containing feedstocks at elevated temperatures.