Study On System Of Asymmetric Biological Hydrogenation Controlled By Light And Its Application

Since Pasteur had synthesized the pure chiral compounds, the synthesis of enantiomerically pure compounds is increasingly important for the development of chemistry and biochemistry. Optical active compounds can be produced by chemical synthesis or biological synthesis. Because chiral alcohols is important building block in pharmaceutical and agrochemical industries, asymmetric reduction of ketones with biocatalysts is now recognized as a valuable approach to the organic synthesis of optically active compounds.In this thesis, the reduction ability of beer yeast and other biocatalysts to acetophenone was studied, the inside reaction mechanism, the reaction effects in water or organic system, lighting souce, pH, reation time and adding mode of acetophenone were tested. Rhodobacter sphaeroides was also studied as biocatalysts, and several ketones including aliphatic ketones and aroma ketones could be reducted with high enantioselectivity.Sreeening conclusion shows that beer yeast have high ability of reduction of acetophenone besides Aspergillus niger and Aspergillus oryzae, and the yield was 34%. But photosynthetic Bacteria has higher ability of reduction than that of yeast.For the reduction of acetophenone in water system, the yield was above 90% and e.e.is up to 99%. Lighting was the basic factor for the reaction, tungsten lighting was suit for the reaction. The optimum pH was 7-8. The yields increased with time, The optimum reaction time was 72 hours. The optimum substrate concentration was 17mmol/L.In the water-organic solvents system, the yield and e.e. were 35% and 97%, respectively. The optimum shake speed was 120-140rpm. The yield was deeply affected by LgP. Petroleum ether was used as organic solvents in the system. The volume ratio of water phase to organic solvents was 1:1 and the reation time was 72 hours.Other ketones were studied in this system. Petroleum ether as goodorganic solvent was also used. The yields was above 70% and e.e. was between 90% and 99% except for 2-heptanone. General speaking, photosynthetic bacteria: Rhodobacter sphaeroides was good biocatalysts on asymmetric reduction of ketones.