Thermoascus aurantiacus CBS 181.6

Credit: Corinne Darmond

Genome Project

— Genozymes Project, Concordia University

EST Project

— Centre for Structural and Functional Genomics, Concordia University

Species Information (from MycoBank)

Current name

Thermoascus aurantiacus Miehe 1907 

Morphic status

Teleomorph (anamorph unknown)

Lineage (from MycoBank)

Ascomycota; Eurotiomycetes; Eurotiales; Trichocomaceae; Thermoascus


Known substrates for isolation of Thermoascus aurantiacus include: soils, peat, self-heated hay, wood chip piles, sawdust, mushroom compost, stored grains, cacao husks, tobacco (1). The optimal temperatures reported for hyphal growth are between 45 and 52.5 oC (2,3), and for ascospore germination between 47.5 and 60 oC (4). So far, more than 60 strains of T. aurantiacus available in public repositories have been isolated from sources in Africa, Asia, Australia, Europe, North America and South America (5).

Interesting Features

Decomposer of lignocelluloses

T. aurantiacus grows efficiently on various lignocellulosic substrates (6-8). Therefore, abundant and low-cost agro-industrial and forest residues/wastes can be used to cultivate this fungus for production of enzymes.

Thermoactive enzymes

Extracellular enzymes of T. aurantiacus that have been characterized include: for cellulolysis, cellobiohydrolase (9-11), endoglucanase (6,9,12,13), and -glucosidase (9,14,15); for hemicellulose degradation, alpha-D-glucuronidase (16); xylanase (6,9,17-19), -xylosidase(12,19), -mannosidase (20), and arabinofuranosidase (21); for pectin degradation, pectin lyase (22), polygalacturonase (23); for starch hydrolysis, amylase and -glucosidase(24-27). All these enzymes exhibit temperature optima of 65 oC or higher.

A laccase-producing strain of T. aurantiacus was capable of causing significant loss of lignin in sawdust. The optimal temperature for the laccase-catalyzed oxidation of o-dianisidine was observed between 70 and 80 oC at pH 2.8 (28,29).

Recently, thermostable superoxide dismutase (SOD) (30,31) and proteases (32,33) from T. aurantiacus have also been attracting interest.

Infections /toxicity

Animal and human infections appear to be rare. T. aurantiacus has been reported from the small intestine of a laboratory mouse maintained on straw, and from the bronchial wash sample of a farmer with pulmonary infarction (34). The organic solvent-extracted portion of the T. aurantiacus culture exhibited toxicity in bioassays using brine shrimp larvae, chicken embryos, and rats (35).


1. Salar RK, Aneja KR (200&) Thermophilic fungi: taxonomy and biogeography. J Agric Technol 3: 77-107.

2. Rosenberg S L (1975) Temperature and pH optima for 21 species of thermophilic and thermotolerant fungi. Canadian Journal of Microbiology 21: 1535-1540.

3. Machuca A, Duran N (1996)Optimization of some parameters influencing Thermoascus aurantiacus growth: Effects of lignin-related compounds. Journal of Industrial Microbiology 16: 224-229.

4. Deploey JJ (1995) Some Factors Affecting the Germination of Thermoascus aurantiacus Ascospores. Mycologia 1995, 87, 362-365.

5. Global Biodiversity Information Facility.

6. da Silva R et al. (2005) Production of xylanase and CMCase on solid state fermentation in different residues by Thermoascus aurantiacus miehe. Brazilian Journal of Microbiology 36: 235-241.

7. dos Santos E et al. (2003) Kinetics of the solid state fermentation of sugarcane bagasse by Thermoascus aurantiacus for the production of xylanase. Biotechnol Lett 25: 13-16.

8. Kawamori M, Takayama K, Takasawa S (1987) Production of Ethanol from Biomasses .6. Production of Cellulases by a Thermophilic Fungus, Thermoascus aurantiacus A-131. Agricultural and Biological Chemistry 51: 647-654.

9. Khandke KM, Vithayathil PJ, Murthy SK (1989) Purification of xylanase, beta-glucosidase, endocellulase, and exocellulase from a thermophilic fungus, Thermoascus aurantiacus. Arch Biochem Biophys 274: 491-500.

10. Hong J et al. (2003) Cloning of a gene encoding thermostable cellobiohydrolase from Thermoascus aurantiacus and its expression in yeast. Applied Microbiology and Biotechnology 63: 42-50.

11. Voutilainen SP et al. (2008) Cloning, expression, and characterization of novel thermostable family 7 cellobiohydrolases. Biotechnology and Bioengineering 101: 515-528.

12. Gomes I et al. (2000) Simultaneous production of high activities of thermostable endoglucanase and beta-glucosidase by the wild thermophilic fungus Thermoascus aurantiacus. Appl Microbiol Biotechnol 53: 461-468.

13. Parry NJ et al. (2002) Biochemical characterization and mode of action of a thermostable endoglucanase purified from Thermoascus aurantiacus. Archives of Biochemistry and Biophysics 404: 243-253.

14. Parry NJ et al. (2001) Biochemical characterization and mechanism of action of a thermostable beta-glucosidase purified from Thermoascus aurantiacus. Biochemical Journal 353: 117-127.

15. Bedino S, Testore G, Obert F (1985) Comparative study of glucosidases from the thermophilic fungus Thermoascus aurantiacus Miehe. Purification and characterization of intracellular beta-glucosidase. Ital J Biochem 34: 341-355.

16. Khandke KM, Vithayathil PJ, Murthy SK (1989) Purification and characterization of an alpha-D-glucuronidase from a thermophilic fungus, Thermoascus aurantiacus. Arch Biochem Biophys 274: 511-517.

17. Alam M et al. (1994) Production and Characterization of Thermostable Xylanases by Thermomyces lanuginosus and Thermoascus aurantiacus Grown on Lignocelluloses. Enzyme and Microbial Technology 16: 298-302.


18. Gomes DJ, Gomes J, Steiner W (1994) Production of Highly Thermostable Xylanase by a Wild Strain of Thermophilic Fungus Thermoascus aurantiacus and Partial Characterization of the Enzyme. Journal of Biotechnology 37: 11-22.


19. Yu EKC et al. (1987) Production of Thermostable Xylanase by a Thermophilic Fungus, Thermoascus aurantiacus. Enzyme and Microbial Technology 9: 16-24.


20. Gomes J et al. (2007) Production of thermostable beta-mannosidase by a strain of Thermoascus aurantiacus: Isolation, partial purification and characterization of the enzyme. Enzyme and Microbial Technology 40: 969-975.


21. Roche N, Desgranges C, Durand A (1994) Study on the Solid-State Production of a Thermostable Alpha-L-Arabinofuranosidase of Thermoascus aurantiacus on Sugar-Beet Pulp. Journal of Biotechnology 38: 43-50.

22. Martins ES et al. (2002) Solid state production of thermostable pectinases from thermophilic Thermoascus aurantiacus. Process Biochemistry 37: 949-954.


23. Martins ES at al. (2007) Purification and characterization of polygalacturonase produced by thermophilic Thermoascus aurantiacus CBMAI-756 in submerged fermentation. Antonie Van Leeuwenhoek International Journal of General and Molecular Microbiology 91: 291-299.

24. Bedino S, Testore G, Obert F (1983) Multiple forms of intracellular alpha-glucosidase from Thermoascus aurantiacus Miehe: purification and properties. Ital J Biochem 32: 371-384.

25. Carvalho AFA et al. (2010) Purification and Characterization of the alpha-Glucosidase Produced by Thermophilic Fungus Thermoascus aurantiacus CBMAI 756. Journal of Microbiology 48: 452-459.

26. Jayachandran S, Ramabadran R (1970) Production of amylase by Thermoascus aurantiacus Miehe. Indian J Exp Biol 8: 344.

27. Ohno, N et al. (1998) Amylases produced by a thermophilic fungus, Thermoascus aurantiacus, and some of their properties. J. Fermentation Bioengineering 85: 458.


28. Machuca A, Duran, N (1993) Phenol Oxidases Production and Wood Degradation by a Thermophilic Fungus Thermoascus aurantiacus. Applied Biochemistry and Biotechnology 43: 37-44.

29. Machuca A, Aoyama H, Duran, N (1998) Production and characterization of thermostable phenol oxidases of the ascomycete Thermoascus aurantiacus. Biotechnology and Applied Biochemistry 27: 217-223.

30. Shijin E et al. (2007) Purification, characterization, and molecular cloning of a thermostable superoxide dismutase from Thermoascus aurantiacus. Bioscience Biotechnology and Biochemistry 71: 1090-1093.

31. Song NN et al. (2009) Cloning, expression, and characterization of thermostable manganese superoxide dismutase from Thermoascus aurantiacus var. levisporus. J Microbiol 47: 123-130.

32. Li AN et al. (2011) Cloning, expression, and characterization of serine protease from thermophilic fungus Thermoascus aurantiacus var. levisporus. J Microbiol, 49: 121-129.

33. Merheb CW et al. (2007) Partial characterization of protease from a thermophilic fungus, Thermoascus aurantiacus, and its hydrolytic activity on bovine casein. Food Chemistry 104: 127-131.


34. Pore RS Larsh HW (1967)First occurrence of Thermoascus aurantiacus from animal and human sources. Mycologia 1967, 59, 927-928.

35. Davis ND et al. (1975) Toxigenic thermophilic and thermotolerant fungi. Appl Microbiol 29 455-457.