Brief SummaryRead full entry
Biology and Interaction with Humans
As mentioned earlier Rhizopus microsporus can cause disease in humans and plants, although it seems to be more of a problem in humans. A potential reason for this might be because the optimal growth temperature for R. microsporus is between 36-40 degrees Celsius, which our body temperature falls within. R. microsporus sensu lato, causes disease in the intestines of people who have compromised immune systems, which can make infection fatal. For example, there have been outbreaks of R. microsporus in cancer patients undergoing treatment (Cheng et al 2009). Many outbreaks of zygomycosis due to R. microsporus has been associated with wooden materials, such as tongue depressors, in healthcare systems and immunocompromised people (Cheng et al 2009). In rice, it is the toxin produced by the endosymbiotic bacteria that causes blight diseases (Partida Martnez and Hertweck 2005). The presence of rhizotoxin particularly affects seedlings where it prevents cell division in the roots. This is what causes the common symptom of swelling in the roots (Scherlach et al 2006).
Despite its impacts to plants and people, it does have some positive qualities. The Netherlands and Indonesia are two countries that use R. microsporus var. oligosporus in the fermentation process of tempeh production (Shambuyi 1992). The usage of R. microsporus variants is different between the Netherlands and Indonesia. The Netherlands typically prefer to use bacteria to start fermentation because the first step in their large scale operations is to rehydrate pre-hulled soybeans. Lactic acid is added during this soaking step to prevent spoilage, which inhibits fungal growth (Nout and Kiers 2005). Smaller operations in Indonesia manually remove the soybean hulls, so they are not letting the soybeans sit in water. Without the addition of lactic acid, fungal starter can be used for the fermentation step.