A large scale enzyme screen in the search for new methods of silicon–oxygen bond formation

Enzyme-Catalyzed Transetherification of Alkoxysilanes

“…One of the biphasic-aqueous organic systems employed during the alkoxysilane studies consisted of 1-octanol saturated with tris-buffered water. In addition to the previously observed enzyme-catalyzed hydrolysis and condensation of alkoxysilanes [9], the formation of the octylsilyl ethers as a result of transetherification and/or silanol-alcohol condensation/exchange was also detected in this solvent whereas no equivalent reaction was seen in the negative control reactions (Scheme 1). The "side-product" octyl-silyl ether was identified as a new peak which appeared in the gas-chromatogram following reaction and work-up when compared to our standard set of peaks which arise from solvents (THF, ethanol and 1-octanol), unreacted starting material, hydrolyzed silanol, and the disiloxane condensation product.…”

“…In similar conditions, no condensation was observed in the negative control reactions nor in the presence of all the other enzymes tested in the Si-O bond formation screening [9]. Figure 1 shows percentage yield of octyl-ether formation based on the quantitative chromatographic data, the mass balance being completed by either unreacted alkoxysilane, silanol formed by simple hydrolysis, or the corresponding disiloxane from the condensation product with another molecule of silanol (see Scheme 1).…”

“…Our group has extensively studied silica precipitation [6] and the enzyme-catalyzed hydrolysis and condensation of alxokysilanes [7][8][9] under mild conditions. We have discovered several enzymatic candidates which were able to perform such reactions at room temperature and neutral pH and have investigated the potential involvement of their respective active sites in the biocatalyzed organo-silicon transformations.…”

Evolutionary selection of enzymatically synthesized semiconductors from biomimetic mineralization vesicles

“…This study adds to growing evidence that enzymatic routes to new materials, as exploited in biomineralization, may be effectively harnessed to produce technological materials (3,23,24,32,40,43,45,46). A typical enzyme, in a properly folded conformation, presents both a chemically catalytic active site and a solution-exposed surface with specific surface chemistry and atomicscale topological features.…”

“…The close genetic relationship of the silicateins with the cathepsin family of digestive proteases and the larger superfamily of hydrolases shows that nature has evolutionarily recruited enzymes with other functions to control biomineralization. Recently, members of this enzyme superfamily (42,43), as well as other enzyme families (45,46) that do not normally catalyze mineral synthesis, have been shown to exhibit catalytic mineralization activity in vitro, suggesting that a wide variety of enzymes may be suitable candidates for directed evolution toward new, specific mineral-synthesis activities. The broad biotechnological capacity to evolve and reengineer enzymes suggests exciting possibilities for further mimicking this natural evolutionary process, and directing enzyme evolution toward the development of new solid-state materials.…”