Medium for enzymes

The medium for enzyme production was completely synthetic and limited in carbon to prevent excessive growth of mycelia. It contained glucose 2 g/l plus ammonia nitrogen, vitamins and trace elements according to Leisola et al.(ii). The 100 1 inoculum was transferred into 8001 of medium in a 10001 bioreactor equipped with 12 rrfi of nylon wool sheets supported by steel wire screen (Figure 1). The medium was continuously stirred with the impeller (100-200rpm) and saturated with pure oxygen. The temperature was maintained at 37°C. 

Although water is the natural medium for enzymes, organic solvents are widely used to improve the solubility of hydrophobic reactants or products, and to shift... 

Because of their tunable properties, supercritical solvents provide a useful medium for enzyme-catalyzed reactions.f The mechanism of enzyme-catalyzed reactions is similar to the mechanism described for solid-catalyzed reactions. External as well as internal transport effects may limit the reaction rate. Utilizing supercritical fluids enhances external transport rate due to increase in the diffusivity and therefore mass transfer coefficient. Internal transport rate depends on the fluid medium as well as the morphology of the enzyme. Supercritical fluids can alter both. 

Excellent medium for enzyme activity and biodegradation, e.g. of waste... 

Water is the usual reaction medium for enzymes however, organic solvents or cyclodextrins can be added to increase the solubility of poorly soluble compoimds. While multienzyme donor recycling systems can be used for in situ donor production [12,19], the following examples utilize stoichiometric donors. 

A mycelial mat (2x2 mm ) was incubated in the medium for enzyme production in a 100-ml Erlenemyer flask for 5 days at 28°C using a rotary shaker. The amount of reducing sugar was measured using 3, 5-dinitrosalicylic acid. Two flasks were used for a strain. These values are average. 

Although supercritical CO2 is by far the most extensively used supercritical medium for enzymes, there are other possibilities. Kamat succesfully tested supercritical fluoroform, ethylene, ethane, propane and sulfur hexafluoride as dispersants for Candida cylindracea lipase in alcoholysis. Interestingly, sulfur hexafluoride, an anhydrous inorganic supercritical solvent, was the best solvent for the tested compounds (2-ethylhexanol and methylmethacrylate) [18]. 

Hydrogels have been used to generate semi-wet pep-tide/protein arrays. By using an LMWG, hydrogel spots were created in an array format, and it was demonstrated that the semi-wet gel interior was a suitable environ-ment/reaction medium for enzymes, whereas the hydrophobic fiber interiors could be used to monitor the reaction. In a proof-of-principle experiment, lysyl-endopeptide (LEP) was used as the enzyme catalyst. A pentapeptide... 

Nakaya, H., O. Miyawaki, and K. Nakamura. 2001. Determination of Log P for Pressurized Carbon Dioxide and Its Characterization as a Medium for Enzyme Reaction. Enzyme and Microbial Technology 28 (2-3) 176—182. 

M Habulin, V Krmelj, Z Knez. Supercritical carbon dioxide as a medium for enzymically catalyzed reaction. Proc Technol Proc 12 (High Pressure Chem Eng), 85-90, 1996. 

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