| In the essay Streptomyces albulus was considered as tool of production, in order to improve the productivity of e -PL, optimize the process of fermentation, make out the rules of batch fermentation and fed-batch fermentation of -PL, works were done as follows: (1) the breeding of the strain producing e -PL. (2)the effect of stir velocity, pH, aeration and temperature on the synthesis of -PL in batch fermentation (3)the fed-batch fermentation was studied and the secondary and space structure of -PL was predicted by using of bioinformatics and internet prediction serve.Streptomyces albulus 9-5 was treated by UV, the optimum irradiation time was 45S. After mutation, initial selection and repeat selection, a mutant UV3-9(AECr) producing -PL 1.085g/L was obtained. The main findings that the capability of fermentation of UV3-9 was higher than 9-5 are as follows: the procrastinate period of UV3-9 was decreased, and the logarithm growth period of UV3-9 was increased; the strains grew rapidly and the capability of e -PL-producing was increased, which is 13% higher than original strain9-5. In order to investigate the genetic stability, the mutant was test after five continuous inoculation. The results showed that the mutant could transfer the genetic information to the son generation.By adding D-Biotin(200~500 g/L) , the capability of -PL-producing can also be increased 35 %.The researches showed that the stir velocity, pH, aeration ratio and temperature play on important roles in the fermentation of -PL in 5-L automatic fermentation jar. High stir speed would improve the growth of cells and the synthesis of -PL, however over high stir speed could break the mycelium so as to get the cells to death. The test showed that at about 350r/min of stir speed the yield of -PL fermentation was the highest. When pH was controlled under low value, which could inhibit the growth of cells. In reverse when pH was higher than 4.5, which could promote the metabolic ability of cells. But high pH would not benefit the synthesis of -PL, the reason was not clarified until now.The field of -PL was enhanced companying with the increasing of aeration ratio. The highest yield of glucose to -PL and productivity were 0.072 g. -PL/g.sub and 0.007g. -PL/g.cell-h under aeration ratio 1.25vvm.Under aeration ratio 2.67vvm dissolved oxygen could maintain over 60%,glucose was consumed slowly and still had 1.05% at 96h, Yx/s was 0.393 g.cell/g.sub, but the 拢 -PL producing lever was fell and the fermentation circle was protracted.The temperature for Streptomyces albulus to grow was 28 C,the yield of glucose to Streptomyces albulus was 0.429 g.cell/g.sub, the field of Streptomyces albulus was 10.07g/L after the batch fermentation, the field of 拢 -PL was only 0.79g/L.30 掳C was fit for the 拢 -PL producing, at which the field of e -PL and the yield of glucose to 拢 -PL, higher than those at 28 C or 32 C,were 2.44g/L and 0.073g. E -PL/g.sub, respectively.,Batch fermentation of e -PL in 5.0L bioreactor was carried out at suitable culture conditions of : agitation speed 350r/min,temperature 30 C, aeration 0.8vvm and adjust aeration 1.25vvm when DO was 30%,pH6.8,and control pH4.0 by adding 10% ammonia as soon as pH was under 4.0.The field of Streptomyces albulus, E -PL concentratin, the yield of glucose to E -PL and volumetric productivity were 10.84g/L,3.02g/L,0.075g. 拢 -PL/g.sub and 0.016 g. 拢 -PL/g. cell-h, respectively.Three different kinds of feed-batch cultures were designed in order to investigate the effect taken by each on e -PL fermentation. These ways included span feed-batch and varible speed feed-batch, as well as constant speed feed-batch which were controlled by substrate feedback based on feed math models. The math model used by the span feed fermentation was Vi X Csi + F X F Si = V2 XCS2, the other was F=dQ/dt=K(t-ta)(t - tL) and Q=cK (c is constant number) . Here the feedback signal was the concentration of glucose which was maintained around lOg/L. Once the concentration of glucose during fermentation process decre...
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