Improvement in extracellular protease production by the marine antarctic yeast Rhodotorula mucilaginosa L7

Abstract

Microorganisms from extreme and restrictive eco systems, such as the Antarctic continent, are of great interest due to their ability to synthesize products of commercial value. Among these, enzymes from psychrotolerant and psychrophilic microorganisms offer potential economical benefits due to their high activity at low and moderate temperatures. The cold adapted yeast Rhodotorula mucilaginosa L7 was selected out of 97 yeasts isolated from Antarctica as having the highest extracellular proteolytic activity in preliminary tests. The present study was aimed at evaluating the effects of nutrient composition (peptone, rice bran extract, ammonium sulfate, sodium chloride) and physicochemical parameters (temperature and pH) on its proteolytic activity. A 2 fractional factorial design experiment followed by a central composite design (CCD 2) was performed to optimize the culture conditions and improve the extracellular proteolytic activity. The results indicated that the presence of peptone in the medium was the most influential factor in protease production. Enzymatic activity was enhanced by the interaction between low glucose and peptone concentrations. The optimization of culture conditions with the aid of mathematical modeling enabled a c. 45% increase in proteolytic activity and at the same time reduced the amount of glucose and peptone required for the culture. Thus culture conditions established in this work may be employed in the biotechnological production of this protease.

Cold-adapted enzymes produced by fungi from terrestrial and marine Antarctic environments

“…In the study performed by Duarte et al [18], 14% of the Antarctic yeasts were able to produce proteases in solid and liquid media. Rhodotorula mucilaginosa L7 produced the greatest amounts of enzyme [106]. The extracellular acid protease from the R. mucilaginosa L7 was active at temperatures ranging from 15.0 to 60.0 C [81].…”

Fungal Peritonitis Caused by Rhodotorula mucilaginosa in a CAPD Patient Treated with Liposomal Amphotericin B: A Case Report and Literature Review

“…We eventually decided to perform the procedure only if a straight TK catheter was used. Secondly, disruption of the intraluminal biofilm and subsequent peritonitis following the transcatheter manipulation is of great concern, but in previous reports, as well as in our patients, there were no episodes of peritonitis after the procedures (3,5,6). In any case, attention must be paid in cases with a history of catheter contamination or visible particles in the catheter lumen.…”

“…DISCuSSIOn rhodotorula mucilaginosa is a common environmental yeast that is isolated from the air, the ocean, the soil, and plants (3). In humans, it is a temporary commensal microorganism of the skin, nails, and gastrointestinal, urinary, and respiratory tracts (4,5).…”

Victoriomyces antarcticus gen. nov., sp. nov., a distinct evolutionary lineage of the Cephalothecaceae (Ascomycota) based on sequence-based phylogeny and morphology

“…Polar microfungi are being studied not only because of a growing interest in biodiversity from extreme environments [15][16][17][18], but also owing to their considerable biotechnological potential. Indeed, such microfungi possess peculiar features such as psychrophilic enzymes that are adapted to temperatures even below À20 C [19], increases in unsaturated membrane lipids [20] and valuable carotenoid pigments [21].…”