Rhizopus oligosporus

Rhizopus oligosporus
White layer of Rhizopus oligosporus on homemade tempeh
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Fungi
Division: Mucoromycota
Class: Mucoromycetes
Order: Mucorales
Family: Mucoraceae
Genus: Rhizopus
Species:
R. oligosporus
Binomial name
Rhizopus oligosporus
Saito

Rhizopus oligosporus is a fungus of the family Mucoraceae and is a widely used starter culture for the production of tempeh at home and industrially. As the mold grows it produces fluffy, white mycelia, binding the beans together to create an edible "cake" of partly catabolized soybeans. The domestication of the microbe is thought to have occurred in Indonesia several centuries ago.[1]

R. oligosporus is the preferred starter culture for tempeh production for several reasons. It grows effectively in the warm temperatures (30–40 °C or 85–105 °F) which are typical of the Indonesian islands; it exhibits strong lipolytic and proteolytic activity, creating desirable properties in tempeh; and it produces metabolites that allow it to inhibit and thus outcompete other molds and gram-positive bacteria, including the potentially harmful Aspergillus flavus and Staphylococcus aureus.[2][3]

R. oligosporus is at present considered to be a domesticated form of Rhizopus microsporus, resulting in a synonym of Rhizopus microsporus var. oligosporus. R. microsporus produces several potentially toxic metabolites, rhizoxin and rhizonins A and B, but it appears the domestication and mutation of the R. oligosporus genome has led to the loss of genetic material responsible for toxin production.[4] The synonym is not currently recognized in fungal taxonomy, so its current taxonomic position is best described as a member of the R. microsporus species group.[5]

  1. ^ Shurtleff, W. & Aoyagi, A. 2001. The book of tempeh. 2 2. Ten Speed Press. Berkeley, California pp.
  2. ^ Nout, M.J.R. (1989). "Effect of Rhizopus and Neurospora spp. on growth of Aspergillus flavus and A. parasiticus and accumulation of aflatoxin B1 in groundnut". Mycological Research. 93 (4): 518–523. doi:10.1016/s0953-7562(89)80046-2.
  3. ^ Kobayasi, Sin-ya; Naoto, OKAZAKI; Takuya, KosEKI (1992). "Purification and Characterization of an Antibiotic Substance Produced from Rhizopus oligosporus IFO 8631". Biosci. Biotechnol. Biochem. 56 (1): 94–98. doi:10.1271/bbb.56.94. PMID 1368137.
  4. ^ Jennessen, J.; Nielsen, K.F.; Houbraken, J.; Lyhne, E.K.; Schnürer, J.; Frisvad, J.C.; Samson, R.A. (2005). "Secondary metabolite and mycotoxin production by the Rhizopus microsporus group". Journal of Agricultural and Food Chemistry. 53 (5): 1833–1840. doi:10.1021/jf048147n. PMID 15740082. S2CID 43834334.
  5. ^ Cite error: The named reference sporangiospores2008 was invoked but never defined (see the help page).