| Trehalose is a unique sugar capable of protecting biomolecules against environmental stress. The wide range of applications of this sugar has increased the interest of many research groups into the development of novel and economically feasible production systems. This thesis primarily optimized the process of trehalose production from Micrococcus (QS412) based on the previous achievements of our research group, and then investigated the feasibility of trehalose production from other bacterium(Cellulomonas sp.).The fermentation trial of QS412 in 20L fermentation tank with cheap culture medium had been done. Compared with result of the fermentation in flask, the period was reduced from 96h to 48h; and the maximal biomass increased thrice; moreover, the enzymatic activity is also improved.The permeabilization method of QS412 with toluene was established. The obtained available permeabilized cells could be used for several batches and at the same time the intracellular enzymes still kept high activity. For example, they could be used at least for 6 batches (if 12h per batch), and the average trehalose concentration was 32.03mg/ml; they also could be used for 16 batches (if 4h per batch), and the trehalose concentration kept steadily above 30mg/ml before 14th batch.The enzyme reaction speed of permeabilized cells was directly correlative to the substrate concentration; the substrate volume would influence on the reaction time to reach equilibrium; in the mass production, 5% starch could be selected to get high conversion rate, the conversion rate could reach 75.38% when reaction time was 24h.The separation & purification method was also discussed. The enzymatic reaction liquid should be firstly added into amylases to decompound the superfluous amylose, and then be wiped off protein by hollow fiber membrane module. After that, the liquid could be treated by active carbon column. 300ml liquid would be adsorbed by the column at the speed of 1ml/min; then the column was washed until the conductance of the effluent was below 100us/cm2; in the end, it is washed again with 10% alcohol in the speed of 1ml/min; the effluent was collected between 1-3 times of column volume. The abtained effluent had little impurity and could be applied for the following concentration and crystallization. The concentration effect of two types of nanofiltration membranes on trehalose-ethanol-water system was studied, the result showed that these two membranes had different character in flux of solvents & rejection of solute, but both of them couldn't adapt for mass production. Crystallization method is as following: adding 3 volume of alcohol to 60% trehalose solvent, and beating up in 30℃. the obtained purity of the crystal is 95.4%,rate of yield is 91.5%. The obtained purity of the re-crystal is 97%,rate of yield is 85.0 %～90.1%. The crystal was detected by HPLC and MRI, and proved to be trehalose.The production feasibility of Cellulomonas sp. was also investigated. From the study of the effects of two carbon sources on the growth and metabolism of the bacterium, we found that although the bacterium could product trehalose in both medium, the biomass and enzymes yielded were different. The yield of trehalose by Cellulomonas sp. was much less than that of Micrococcus (QS412), so Cellulomonas sp has little feasibility to be be industrialized.
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