Rhizomucor pusillus

Credit: Corinne Darmond

Genome Project

– Genozymes, Concordia University

Species Information (from MycoBank)

Current name

Rhizomucor pusillus (Lindt) Schipper 1978 [1]  


Mucor pusillus Lindt 1886

Taxonomic synonyms
Mucor buntingii Lendner1930
Mucor parasiticus Lucet & Costantin 1899
Rhizomucor parasiticus (Lucet & Costantin) Lucet & Costantin 1900
Rhizopus parasiticus (Lucet & Costantin) Lendn. 1908
Mucor septatus Bezold 1889
Rhizomucor septatus (Bezold) Lucet & Costantin 1901

Morphic status


Lineage (abbreviated from NCBI Taxonomy Browser)

Fungi; Mucoromycotina; Mucorales; Mucoraceae; Rhizomucor


Rhizomucor pusillus is distributed worldwide and is mainly found on composting and fermenting substrates such as compost, municipal wastes, hay, straws, and dung [2].  Temperature growth range is the following: minimum 21-24 oC; optimum 35-45 oC; maximum 55oC. The optimum pH for growth is 6.1 [1, 3].

Interesting Features

Decomposer of lignocellulose

Rhizomucor pusillus has been reported to be unable to degrade filter paper or carboxymethylcellulose [4-6] or lignocelluloses in the form of newsprint [5]. Nonetheless, cellulolytic enzyme activities were detected in supernatants of cells cultured on wheat bran [7] : endoglucanase and beta-glucosidase activities were induced by CMC [8]. Taken together, these results indicate that this organism is weakly cellulolytic. When grown on sugar beet pulp, under conditions where other species of thermophilic fungi produced xylanases, R. pusillus produced only very low levels of xylanase activity [9].

Thermoactive enzymes

Extracellular enzymes of Rhizomucor pusillus that have been characterized include: alpha-L- arabinofuranosidase [10], alpha-amylase [11-15], phytase [16], aspartic protease (MPP) [17-19] and lipase [20]. These enzymes have temperature optima of 50 ºC and above.

Industrial application

Rhizomucor pusillus aspartic protease is a major enzyme in industrial cheese production [21]


R. pusillus is sometimes associated with human infections,  generally in immunocompromised patients, e.g. [13]


1. Schipper MAA (1978) On the genera Rhizomucor and Parasitella. Studies in Mycology 17: 53-68.


2. Salar RK and Aneja KR (2007) Thermophilic Fungi: Taxonomy and Biogeography. J Agric Tech 3(1): 77-107.


3. Rosenburg SL (1975) Temperature and pH optima for 21 species of thermophilic and thermotolerant fungi. Can. J. Microbiol. 21:1535-1540


4. Fergus CL (1969) The Cellulolytic Activity of Thermophilic Fungi and Actinomycetes. Mycologia 61: 120-129


5. Rosenberg SL (1978) Cellulose and lignocellulose degradation by thermophilic and thermotolerant fungi. Mycologia 70:1-13.


6. Tansey, MR (1971). Agar-diffusion assay of cellulolytic ability of thermophilic fungi. Arch für Mikrobiol. 77: 1-11


7. Somkuti GA, Babel FJ and Somkuti AC (1969) Cellulolysis by M. pusillus. Appl and Environ Microbiol. 17: 888–892


8. Somkuti GA (1974) Synthesis of Cellulase by Mucor pusillus and Mucor miehei. Microbiology 81(1): 1-6


9. Grajek W (1987) Production of D-xylanases by thermophilic fungi using different methods of culture. Biotech Lett. 9: 353-356. http://www.springerlink.com/content/m1r501193347365g/fulltext.pdf

10. Rahman AKMS, et al. (2001) Physicochemical properties of a novel alpha-L-arabinofuranosidase from Rhizomucor pusillus HHT-1. Can J Microbiol. 47(8): 767-772.


11. Fergus CC (1969) The production of amylase by some thermophilic fungi. Mycologia 61:1171-1175.


12. Somkuti GA, Steinberg DH (1980) Thermoacidophilic extracellular amylase of Mucor pusillus. Dev Indust Microbiol 21:327-33

13. Deploey, J.J., M. Nasta, and P.R. Adams, Quantitative-Determinations of the Temperature and pH Stability of Extracellular Amylase Obtained from Mucor Pusillus. Mycologia, 1982. 74(5): p. 847-850.


14. Turchi SL and Becker T (1987) Improved Purification of Alpha-Amylase Isolated from Rhizomucor pusillus by Affinity-Chromatography. Curr Microbiol. 15: 203-205.


15. Silva TM et al. (2005) Production of saccharogenic and dextrinogenic amylases by Rhizomucor pusillus A 13.36. J Microbiol. 43(6): 561-8.


16. Chadha BS et al. (2004) Phytase production by the thermophilic fungus Rhizomucor pusillus. World J Microbiol Biotech. 20(1): 105-109.


17. Arima K, Yu J, Iwasaki S (1970) Milk-clotting enzyme from Mucor pusillus var. Lindt, In: Gertrude E. Perlmann, Laszlo Lorand, Editor(s), Methods in Enzymology, Academic Press, Volume 19, pp 446-459


18. Arima K, Iwasaki S and Tamura G (1967) Milk-clotting enzyme from microorganisms, part I. Screening test and the identification of potent fungus. Agric Biol Chem. 31: 540–545.

19. Arima K, Yu J, Iwasaki S and Tamura G (1968) Milk-clotting enzyme from microorganisms, part V. Purification and crystallization of Mucor rennin from Mucor pusillus var. Lindt. Appl Microbiol., 16: 1727–1733


20. Somkuti G, Bale, FJ, and Somkuti AC (1969) Lipase of Mucor pusillus. Appl Environ Microbiol. 17(4):606-610


21. Jacob M, Jaros D, and Rohm H (2011) Recent advances in milk clotting enzymes. Int J Dairy Technol. 64: 14–33


22. Iwen PC et al. (2005) Molecular identification of Rhizomucor pusillus as a cause of sinus-orbital zygomycosis in a patient with acute myelogenous leukemia. J Clin Microbiol. 43(11): 5819-5821.