Cystobasidium psychroaquaticum as a new promising source of valuable bioactive molecules

Screening procedure for the selection of yeasts able to produce bioactive molecules continues to be an important aspect of yeast biotechnology. The aim of the present study was to characterize two oleaginous yeasts from WUT Yeast Collection, WUT71 and WUT117, assigned to Cystobasidium psychroaquaticum. The emphasis was put on their ability to accumulate intracellular carotenoids, a valuable health-promoting molecules and to produce extracellular hydrolases, an important biocatalysts. The best carotenogenesis, 3.146 +/- 0.340 mg l(-1), was evaluated for C. psychroaquaticum WUT117 at 15 degrees C, C:N ratio of 20:1 and glucose as the carbon source. Obtained carotenoid extracts were subsequently used in MTT test on HaCaT cell line, showing no cytotoxicity up to 500 mg l(-1). Noteworthy, carotenoids derived from C. psychroaquaticum strains have not been analyzed in this respect so far. The maximum enzymatic activities obtained for C. psychroaquaticum WUT71 and WUT117 were 426.81 U ml(-1) (at 15 degrees C) and 346.69 U ml(-1) (at 20 degrees C), respectively. Hence, two new C. psychroaquaticum strains, capable of producing both carotenoids and hydrolases were identified.