Cell preparation growth medium/substrate

Additional suggestive evidence for the existence of a second distinct fumarase in this fungus comes from the analysis of fumarase activity in cell lysates. Fumarase in lysates of R. oryzae from medium B (growth medium) has a lower value for fumaric acid (0.78 mM) than for L-malic acid (2.9 mM), similar to fumarase from lysates of S. cerevisiae (Pines et al., 1996). Fumarase activities (with L-malic acid as the substrate) in both these lysates were not inhibited by fumaric acid. In sharp contrast, fumarase activity measured in extracts prepared from R. oryzae cells incubated in medium C (production medium), but not with S. cerevisiae, was completely inhibited by 2 mM fumaric acid (E. Battat and I. Goldberg, unpublished data cited in Goldberg et al., 2006). 

During manufacture, the miaobes usually secrete hydrolases into the medium. Purification usually involves removing the cells and concentrating the growth media. Contaminating proteins that do not react with the substrate or produrt are innocuous. Second, the crude preparations contain sugars and other inert carriers that increase the surface area and stabilize the lipases, especially for reactions in organic solvents. 

---