Thermostable Cellulases from the Yeast Trichosporon sp.

Abstract

Objectives. Identification of cellulolytic microorganisms is of great interest to the hydrolysis of cellulosic biomass. This study focuses on the identification of cellulolytic yeasts and the optimization of cellulase activities produced by the best performing isolate. Results. 30 cellulolytic yeast isolates were selected. Enzymes produced by an isolate from the Trichosporon genus showed the property to hydrolyze different substrates: carboxymethyl cellulose (CMC), cellulose fiber, and filter paper (FP). The optimum measured temperature was 55°C for CMCase and 60°C for FPase. The optimal pH was 5 for CMCase and 4 to 6 for FPase. The effect of the substrates concentration showed that the best activities were obtained at 100 mg/mL CMC or FP. The highest activities were 0.52 for the CMCase and 0.56 for the cellulase fiber at 10 min incubation, 0.44 IU/mL at 15 min incubation, and 24 h FPase preincubation. Conclusion. Cellulases produced by the studied yeast are capable of hydrolyzing soluble and insoluble substrates at elevated temperatures and at a wide pH range. They are considerable interest in the production of fermentable sugars from lignocellulosic substrates.

Cellulolytic and Xylanolytic Enzymes from Yeasts: Properties and Industrial Applications

“…The yeasts isolated from animal guts have also been studied for the optimal parameters affecting the growth and production of cellulase. In this context, a yeast strain isolated from a coprophage, Gymnopleurus sturmi, was found to be a promising cellulolytic strain [90]. The data revealed that the enzyme from this strain is capable of hydrolyzing various cellulosic substrates, including insoluble fibers and filter paper (FP); the enzymatic activity remained unaffected with a change in pH and temperatures from 55 to 70 • C. The enzyme showed better catalysis at a higher substrate loading of 100 mg mL −1 of CMC or FP.…”

“…The data revealed that the enzyme from this strain is capable of hydrolyzing various cellulosic substrates, including insoluble fibers and filter paper (FP); the enzymatic activity remained unaffected with a change in pH and temperatures from 55 to 70 • C. The enzyme showed better catalysis at a higher substrate loading of 100 mg mL −1 of CMC or FP. The highest activities of 0.52 IU mL −1 for the CMCase were obtained, while FPase activity needed extended time so that the enzyme could be adsorbed to the substrate [90] (Table 3).…”

“…Both the enzymes showed best activity when reacted with 100 mg/mL of their respective substrates. FPase required more time to catalyze the reaction, probably due to the time taken for adsorption to the insoluble substrate [90] Aureobasidium pullulans 98 Endoglucanase…”

“…Likewise, the cellulases produced by Trichosporon sp. could hydrolyze a variety of cellulosic substrates at elevated temperatures and at a wide range of pH [90]. Such enzymes offer advantages because of their longer half-lives, and their reactions become protected from contamination; moreover, a concentrated solution of sugars can be used at higher temperatures.…”

Characterization of two thermophilic cellulases from Talaromyces leycettanus JCM12802 and their synergistic action on cellulose hydrolysis

“…Cellulose, the major component of plant cell walls, is composed of repeating d -glucose residues linked by β-1,4-glucosidic bonds. It represents the most plentiful sustainable resource on Earth and is widely used for the production of renewable energy [1,2,3]. The complete hydrolysis of cellulose requires the synergy of three types of cellulases: endoglucanase (EG; EC 3.2.1.4) that randomly cleaves the intracellular β-1,4-glucosidic bond of cellulose to release cellooligosaccharides; cellobiohydrolase (CBH; EC 3.2.1.91) that hydrolyzes short cellulose molecules and cellooligosaccharides to cellobiose; and β-glucosidase (BG; EC 3.2.1.21) to degrade cellobiose into glucose [4,5,6]…”