To the best of our knowledge, this is the first report on thermophilic fungi isolated in Korea. Three species of thermophiles were isolated from compost and were identified as Myriococcum thermophilum, Thermoascus aurantiacus, and Thermomyces lanuginosus. They can grow at temperatures above 50degrees C and produce high levels of cellulolytic and xylanolytic enzymes at high temperatures. Notably, the considerable thermostability of the endo-glucanase produced by T. aurantiacus has made the fungus an attractive source of industrial enzymes.
Cellulase ; Fungi* ; Korea ; Soil* ; Thermoascus

The effect of growth and fermentation conditions on the production of catalase by T. aurantiacus WSH 03-01 was investigated in shaking flasks. Catalase activity reached 1594 u/mL when the culture was grown on a complex carbon source containing 20 g/L dextrin and 1% (V/V) ethanol, which was 23% higher than the sum produced on 20 g/L dextrin and 1% (V/V) ethanol, respectively. It was concluded that dextrin might act as a major carbon source in the complex, while ethanol was rather a stimulator than a carbon source. The stimulation effect of ethanol on catalase production was postulated to be two aspects; catalase-dependent alcohol metabolism is activated by acute alcohol, thus more catalase need to be synthesized for that use, named direct induction. As for indirect induction, which may result from little amount of H2O2 generation in process of NADH regeneration in respiratory chain. Peptone was shown to be a favorable nitrogen source for catalase production and its optimum concentration was found to be 10 g/L. Catalase production by T. aurantiacus WSH 03-01 was further improved by optimizing the initial pH, volume of medium in flasks as well as the concentration of external H2O2. Under the optimum culture conditions, the activity of catalase reached 2762 u/mL, which was nearly 6.8 times higher than that of the initiate conditions. Furthermore, the potential application of this novel catalase in the treatment of textile bleaching effluents was evaluated. Thermo-and alkaline stability of this catalase was compared with the commercial available catalases produced from bovine and Aspergillus niger. The crude enzyme from T. aurantiacus WSH 03-01 showed stronger stabilities at (70 degrees C, 80 degrees C, 90 degrees C) and (pH 9.0, pH 10.0, pH 11.0) than the other two types of catalases, indicating a great application potential in the clean production process of textile industry.
Catalase ; metabolism ; Culture Media ; Ethanol ; metabolism ; Fermentation ; Hot Temperature ; Hydrogen-Ion Concentration ; Peptones ; metabolism ; Textile Industry ; Thermoascus ; enzymology ; growth & development

Efficient utilization of cellulose and xylan is of importance in the bioethanol industry. In this study, a novel bifunctional xylanase/cellulase gene, Tcxyn10a, was cloned from Thermoascus crustaceus JCM12803, and the gene product was successfully overexpressed in Pichia pastoris GS115. The recombinant protein was then purified and characterized. The pH and temperature optima of TcXyn10A were determined to be 5.0 and 65-70 °C, respectively. The enzyme retained stable under acid to alkaline conditions (pH 3.0-11.0) or after 1-h treatment at 60 °C. The specific activities of TcXyn10A towards beechwood xylan, wheat arabinoxylan, sodium carboxymethyl cellulose and lichenan were (1 480±26) U/mg, (2 055±28) U/mg, (7.4±0.2) U/mg and (10.9±0.4) U/mg, respectively. Homologous modeling and molecular docking analyses indicated that the bifunctional TcXyn10A has a single catalytic domain, in which the substrate xylan and cellulose shared the same binding cleft. This study provides a valuable material for the study of structure and function relationship of bifunctional enzymes.
Cellulase ; Endo-1,4-beta Xylanases ; Enzyme Stability ; Hydrogen-Ion Concentration ; Molecular Docking Simulation ; Pichia ; Substrate Specificity ; Thermoascus

Many fungi including Penicillium, Aspergillus, Gliocladium, and Thermoascus produce an epipolythiodioxopiperazine class of fungal metabolite, gliotoxin, which contirbutes the pathogenesis of fungal infection as an immunomodulator and cytotoxic agent. This study is designed to define the mechanism by which gliotoxin exerts the cytotoxic effect of gliotoxin on human promyelocytic leukemic cells, HL-60. Gliotoxin induces the apoptosis of HL-60 cells which is characterized by the ladder pattern fragmentation of DNA. Gliotoxin induces the activation of DEVD-specific cysteine protease in a time- and dose-dependent rnanner. It also increases the phosphotransferase activities of c-Jun N-terminal kinase1 (JNK1) and p38 in gliotoxin-treated HL-60 cells. Furthermore, gliotoxin decreases the activation of transcriptional activator, actiating protein (AP-1) and NF-kB. These results suggest that gliotoxin induces the apoptotic death of HL-60 cells via activation of DEVD- specific caspase as well as mitogen activated protein kinases (MAP kinases) including JNK1 and p38, and inhibition of transcriptional activators, AP-1 and NF-kB.
Apoptosis* ; Aspergillus ; Caspase 3 ; Cysteine Proteases ; DNA ; Fungi ; Gliocladium ; Gliotoxin* ; HL-60 Cells* ; Humans ; Mitogen-Activated Protein Kinases ; NF-kappa B ; Penicillium ; Thermoascus ; Transcription Factor AP-1 ; Transcription Factors