Immobilized Lactobacillus Preparation Of Mannitol Process

Mannitol is a basic medicament as well as an important material in pharmaceutical industry. It is always used as a kind of excipients. It is also a fine chemical product which has an extensive use. For example, it is widely used in pharmaceutical and food industry etc. Mannitol has some special physiological functions,as it does not rise the level of blood sugar and destroy our teeth after we eat it. And also it has lower calorie than another kind of sugar. So it is more popular to apply mannitol in sweet additive and food additive industry. Mannitol will be needed more and more all over the world.At present, the traditional ways of producing mannitol are isolation from kelp and chemosynthesis.Isolation needs a lot of kelp, the process will need a lot of water and energy and it does not cause serious pollution, even the quality is also not so good. As the resource of kelp is going to be exhausted, it will become more difficult to ensure the resource. The way of chemosynthesis will produce a lot of subsidiary -sorbitol (account for 3/4 invert sugar) .Zymotechnics can utilize the system of enzyme to produce mannitol and have no subsidiary -sorbitol, because enzyme has a function of select-hydrogenation. As the condition is mild, medium is not to be requested very pure, assistant gene can be regeneration, zymotechnics becomes a very good way to produce mannitol.Lactobacillus buchneri AS 1.0013 biotransformation to produce mannitol is mainly investigated in this thesis. Using spectrophotometry to determine the content of fructose and mannitol in substrate is quite rapid and accuate, the content of fructose is determined at 540nm and the content of mannitol is determined at 412nm. After activating and substrate inducing, the enzyme activity is doubled than before. Its optimum growth condition is pH 6.4, optimum growth temperature 35℃, logarithm growth period 4～10h. Its optimum condition of fermentation is pH6.6, temperature 40℃.The strain can produce mannitol up to 4.592g/L·h.Mechanical intensity and content of mannitol are two factors to investigate the optimal conditions of immobilization.The result is: alginate is 2%, Carrageenan 0.5%, CaCb 2%, the cross linking pH 6.5, the cross linking temperature 35℃, and cells contained 3.75mg/ml alginate). Under these conditions, the strain can produce mannitol up to 3.68 g/L·h. Theactivity recovery rate of this immobilized bacteria can be up to 80% .The property of this immobilized strain is studied. The optimum condition is: concentrate of substrate 8g/L, pH6.6, optimum temperature 40℃, the rotate speed 180r/min. After 20 hours fermentation,the mannitol production rate to tatol quantity of substrate added is up to 78.92%.