【作者】 李新亮；

【导师】 汪钊；

【作者基本信息】 浙江工业大学 ， 生物化工， 2003， 硕士

【摘要】 固定化微生物酯酶反应器适应性广、结构简单、投资省、操作弹性大，但国内外在这方面的研究鲜有报道。本文研究了可手性拆分D，L-乳酸乙酯的产酯酶微生物细胞在气升式生物反应器中的固定化、培养条件、底物拆分性能以及集细胞固定化、发酵、拆分于一体的新型气升式生物反应器性能参数的设计。 为了进一步清晰外循环气升式固定化细胞生物反应器各操作参数对发酵过程的影响，采用均匀设计法进行回归分析。综合考虑得出各操作参数的影响情况：通气量对气升式生物反应器内传质、传氧的影响最大，料液粘度次之，装料量、颗粒浓度、罐压三者因传质、传氧的不同各异。 对集固定化、发酵、拆分于一体的新型外循环气升式固定化生物反应器进行结构设计。鉴于该固定化细胞反应器的实际应用，采用较大的罐体高径比：H／D=4。本文针对对传质、传氧的影响系数大小着重设计了空气喷嘴、筛板（折流元件），并初步定为：喷嘴直径2mm，筛板为5目；针对实验要求设计了一种内部固化装置，该装置底部带有针头，上下通过螺旋连接形成空腔。 通过比较实验，建立起一个有效、简便的细胞固定化模型。采用海藻酸钠／PVA法对微生物孢子固定化，进行发酵培养。以高酶活力力、固化颗粒的高强度／通透性为基准，筛选出最佳固化条件：海藻酸钠3％、PVA8％、CACl₂3％。另外，考察了固化细胞的最适反应条件：温度为45℃、pH6.5、时间为3h。 将固定化细胞在气升式生物反应器中发酵培养，并与游离细胞的摇瓶发酵、搅拌式／气升式反应器发酵进行了比较：固定化细胞在气升式反应器内达到最高酶活力时比游离细胞摇瓶发酵缩短20h，比游离细胞气升式发酵缩短12h。 最后以D，L-乳酸乙酯为底物，通过离子交换法、树脂吸附法和萃取法对产物分离，进行固定化细胞手性拆分性能的研究。结果表明：采用阴离子交换树脂D301分离后L-乳酸的光学纯度可达到84.9％。更多还原

【Abstract】 The immobilized method, cultivating conditions, splitting capability of the microorganism of producing esterase which splits D,L-lactic acetate were studied systematically in this paper. At the same time structure parameters were optimally designed considering the broad application of immobility bioreactor with few researches in this field, and a new-style immobility bioreactor was also designed, which was conveniently operated and easily invested.Equality-design to regression analysis was adopted for the sake of comprehending the effects of parameters on fermentation. The result of integrated consideration showed aerates volume affected oxygenic transfer and substance transfer badly, and viscosity coefficient took second place. Loading volume, immobility cells concentration and the pressure in the pot also affected differently.A new-style immobility cell bioreactor was designed in this paper. Air nozzle, sieve plate were designed mainly on base of the effects on oxygenic transfer and substance transfer, and the diameter of air nozzle is 2mm.A interior equipment with pinheads whose size is 16 to immobilize cells was designed aimed at the experiment request.An available and handy immobility model was set up by experiment. Spores were immobilized by calcium alginate and PVA and then were fermented. The optimal immobility condition that was gotten was calcium alginate3%, PVA8%,CaCl23%. Otherwise , the optimal reaction condition was T45C,pH6.5,3h.Immobility cells were fermented in air-lift bioreactor, at the same time feeling out the growth curve, remnant sugar and pH-variety curve. Subsequently the ending of immobilized cells and dissociate cells was compared. We found that the fermentation cycle of the immobilized cells in ALR shortened 20 hours than the dissociate cells in vase, and shortened 12 hours than the dissociate cells in agitation bioreactor.The splitting capability of immobility cells was studied after the offspring had been separated by ion-exchange and resin-adsorption. The result indicated that the purity of L-lactic acid achieved 84.9%.更多还原