Solvents engineering

Ionic liquids have been shown to be good solvents of carbohydrates including Unear polysaccharides as ceUulose and amylose, hence it has been reported that 

1 Castillo, E., Pezzotti, F., Navarro, A. and Lopez-Munguia, A. (2003) Journal of Biotechnology, 102, 251. 

8 Riva, S., Chopineau,)., Kieboom, A.P.G. and KUbanov, A. (1988) Jourrud of the American Chemical Society, 110, 584. 

20 Patil, N.S., Yanzi, L, Rethwisch, D.G. and Dordick, J.S. (1997) Journal of Polymer Science Part A - Polymer Chemistry, 35 (11), 2221. 

26 Quiroga, E., Cami, G., Marchese, J. and Barberis, S. (2007) Biochemical Er neerir Journal, 35,198. 

Oxidoreductases are active in nonaqueous solvent such as organic solvent, supercritical CO, and ionic liquids although immobilization may be necessary to stabilize the enzyme. Examples of the use of oxidoreductases in nonaqueous solvents are shown in this section. 

Geotrichum candidum NBRC 5767 (immobilized on water-adsorbent polymer) 

Horse liver alcohol dehydrogenase (HLADH) flnorinated NADH, ethanol 

By studying the ring opening of (rac)-2-phenyl-4-benzyl-5(4H)-oxazolone with butanol catalysed by CALB in organic media, it has been possible to correlate the protonation state of the enzyme with the enantioselectivity of the reaction [36]. The protonation state was controlled by the use of either organo-soluble bases or solid-state buffers of known pfC. Both triethylamine and the buffer pair CAPSO/CAPSO.Na [CAPSO = 3-(cyclohexylamino)-2-hydroxy-l-propanesulfonic acid] were found to increase the enantioselectivity of reactions catalysed by CALB and also the lipase from Mucor miehei. The effect of solvent, water activity and temperature on the enantioselectivity of reactions catalysed by lipases and hydroxynitrile lyases (enzymes that catalyse the addition of cyanide to aldehydes) has been reported [37]. 

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The Shodex GPC HFIP series is packed with a hexafluoroisopropanol (HFIP) solvent. Engineered plastics, such as polyamides (nylon) and polyethylene terephthalate, were analyzed previously at a high temperature of about 140°C. Using FIFIP as an eluent, such engineered plastics can be analyzed at ordinary temperatures (Table 6.4). 

The control of the polymer structure was achieved by solvent engineering. The ratio of phenylene and oxyphenylene units was strongly dependent on the solvent composition. In the HRP-catalyzed polymerization of phenol in a mixture of methanol and buffer, the oxyphenylene unit increased by increasing the methanol content, while the buffer pH scarcely influenced the polymer structure. ... 

Using solid/gas reactors to improve enzyme enantioselectivity by solvent engineering and changing reaction conditions... 

Wagner B, Sieber SA, Baumann M et al (2006) Solvent engineering substantially enhances the chemoenzymatic production of surfactin. ChemBioChem 7 595-597... 

The aim of the present chapter is to give a brief overview of protease-catalyzed synthesis of sugar esters in hydrophilic solvents and to present some of the most recent investigations on the effect of these solvents on activity and stability of proteases. Consequently, the perspectives in solvent engineering are outlined with focus on hydrophilic solvents and ionic liquids. 

Chaudhary AK, Kamat SV, Beckman EJ, Nurok D, Kleyle RM, Hadju P, Russell AJ. Control of subtilisin substrate specificity by solvent engineering in organic solvents and supercritical fluoroform. J Am Chem Soc 1996 ... 

Edmundo, C., Valerie, D., Didier, C., and Alain, M., Efficient hpase-catalyzed production of tailor-made emulsifiers using solvent engineering coupled to extractive processing, J. Am. Oil Chem. Soc., 75, 309-313, 1998. 

The shift is indicating a higher thermodynamic stabihty of the folded structure of the enzyme. It is suggested that the stabilization of enzymes by solvent engineering is achieved by raising the stability curve (Fig. 6) (Becktel and Schellman 1987 Rees and Robertson 2001). 

Bellot, J.C., Choisnard, L., Castillo, E., and Marty, A. 2001. Combining solvent engineering and thermodynamic modebng to enhance selectivity during monoglyceride synthesis by lipase-catalyzed esterification. Enz. Microb. Technol. 28 362-369. 

A range of future opportunities exists for the exploitation of SCF solvents in various areas of materials science. The explosive growth of nanoscale materials applications in the last five years points to one such area. Another field that may hold great future promise is SCF solvent engineering in supramolecular chemistry this has, as yet, been Httle exploited, despite the growing understanding that exists concerning micelle formation and self-assembly in SCFs. 

The structure of lipases has been shown to be similar in both water and hydrophobic solvents and binding of solvent molecules other than water has been observed. Rates of reaction and enantioselectivity have been altered by changing the solvent in a process called solvent engineering. 

The integration of molecular-recognition-directed self-assembly and chemistry of bilayer membranes has lead to the development of mesoscopic supramolecular assemblies. The impartment of amphiphilicity to supermolecules drives their hierarchical self-assembly. The solvophilic-solvophobic interactions play a pivotal role in the determination of the supramolecular architecture, and this is a distinct feature from the earlier supramolecular chemistry. The combinatorial supramolecular approach is also effective to develop functional mesoscopic assemblies. In addition, combination of supramolecular polymers and solvent engineering will give a new perspective in the design of mesoscopic materials. 

Niederberger M, Pinna N (2009) Metal oxide nanoparticles in mganic solvents. Engineering materials and processes. Springer, Berlin... 

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