According to former studies, most of the commonly used feedstocks
for fumaric acid production, such as purified sugars, starchy
materials and cellulosic material, encounter various issues that
impeding them from being an ideal raw material. Purified sugars
are expensive for industrial utilization, and using sugars and starchy
materials as feedstocks can directly compete with humans for
food and break the equilibrium of supply and demand of grain
(Tollefson, 2008; Aho, 2007). Furthermore, cellulosic material
could not be directly used for fermentation. It needs to be processed
by acid or cellulase in order to release fermentable sugars
(Huang et al., 2009). The pretreatment processes are complicated
and costly. Hence, searching for economic carbon source is crucial.
Rhizopus arrhizus has been reported as an excellent fumaric acid
producer (Roa Engel et al., 2008), as well as being capable of
producing a high level of fumaric acid when growing on sugar or
starchy materials. However, growing the R. arrhizus on biodieselderived
crude glycerol has not been investigated yet, and only a
few works have been performed to evaluate fumaric acid production
from crude glycerol. Therefore, the objective of this work
was to investigate the potential of using crude glycerol to culture
R. arrhizus and produce fumaric acid.