Extracellular enzymes production in Rhodotorula species

Introduction and Objectives: Rhodotorula species are common airborne contaminant fungi and also considered as normal inhabitants in the skin, lungs, urine and feces in humans. The most common species of Rhodotorula are including; R. mucilaginosa, R. glutinis and R. minuta. Rhodotorula species considered as an important agent for invasive infection among immunocompromised patients. Several studies show that extracellular enzymes such as, phospholipase proteinase and esterase are as pathogenic factors in yeast. The present study, focused on extracellular phospholipase, proteinase, and esterase activities in different isolates of including; R. mucilaginosa, R. glutinis, R. minuta and Rhodotorula species. Materials and Methods: In the present study 68 isolates of different species of Rhodotorula were examined for the production extracellular enzymes. Phospholipase activity assays were performed according to Price et al. using Sabouraud dextrose agar (SDA) supplemented to egg yolk. In addition, proteinase of isolates was evaluated using bovine serum albumin agar medium. Esterase activity was also determined by SDA supplemented to Tween 80. Colony diameter and colony diameter plus precipitation zone were measured for each isolate. Results: The phospholipase activity was detected in 82.4% of Rhodotorula isolates. In the present study phospholipase activity with higher Pz values (<0.70) was seen in 69.1% of isolates. Esterase activity was detected in 29.4% of isolates, whereas 70.6% of them were negative for this enzyme. All isolates of R. mucilaginosa were negative for esterase activity. In the present study all tested isolates were negative for the production of proteinase. Conclusion: Our results show that there are remarkable differences in the enzymatic activity between species of Rhodotorula. In addition, phospholipase activity in Rhodotorula species is remarkable than other extracellular enzymes.

Rhodotorula, Phospholipase, Proteinase, Esterase