Preparation Of Chiral 2-octanol By Biological Method

It is very necessary to obtain pure chiral compounds in drug research and industrial application field. Due to its remarkable advantages such as mild reaction conditions, high-optical purity and little environmental pollution, more and more reseachers pay attention to the biototechnology which is used to synthesize chiral compounds or intermediates. In our experiment, we use candida tropicalis cells for the resolution of raceme in order to obtain pure 2-octanol which is optical selective.In our experiment, we studied the reaction of 2-octanol in a single aqueous phase and then investigated the effects of solubility of 2-octanol in a single aqueous phase, different buffer solution, free cell concentration, substrate concentration, temperature and pH on reaction. The optimum reaction conditions is that:Substrate concentration is 60.0 mmol/L when the biggest solubility in water is about 2.97 mmol/L, using phosphoric acid buffer solution the concentration of free cell 200 g/1、substrate concentration 20mmol/1、30℃ and pH 7.0. It was also discussed that the immobilization study of microorganism in single aqueous phase using the three carriers such as calcium alginate, sawdust and nylon cloth. In all of the three carriers, the calcium alginate is the best one. It is increased significantly for the tolerance of calcium alginate immobilized cells to high substrate concentration. And the optimum substrate concentration comes to 40 mmol/L. It effectively slowed down the substrate inhibition. Preservation in the room temperature is good for the activity of immobilized microorganism cells and the optimum input of immobilized cells is 16 gram.In an aqueous-organic solvent biphasic system, the different organic solvent were studied, the best biphasic system was water/nonane. The reaction conditions were optimized and the optimum conditions is that, the amount of substrate is 40 mmol/L, the volume ratio of phosphoric acid buffer and organic solvent is 15/5, reaction for 40h, pH7.0, temperature 30～34℃ and enough oxygen. We studied the efficiency of the reaction before and after the microorganism cells were immobilized by calcium alginate. The experimental results show that the tolerance of the immobilized cells were improved., the optimum substrate concentration comes to 50 mmol/L, the conversion of immobilized cells was 2.61% more than free cells, the conversion in biphasic system was 4.45% more than in a single aqueous phase. The immobilized cells could be reused for four times still keeping a certain activity and twice keeping high activity.