Abstract: The effect of control modes of pH on 1,13-tridecanedioic(DCA13) acid fermentation by a mutant,Candida tropicalis SP-UV-56, was studied. Decrease in pH is in favor of cells’vitality, but inhibits DCA13 secretion from the cells；while increase in pH is harmful to the vitality,but promotes the secretion of DCA13. Three parameters of C_p,e, pH_e and ΔpH_e were proposed for DCA13 fermentation system.C_p,e as defined as the equilibrium concentration of DCA13 obtained when regulated pH decrease to pH_e.pH_e was defined as the medium pH when cells cease to producte DCA13 due to the drop of medium pH resulting from excretion of DCA13 after automatic control of medium pH (regulated pH) was stopped.ΔpH_e was defined as the difference between regulated pH and pH_e. The relation between pH_e and DCA13 concentration C_p,e and a continuous control strategy of pH based on 0.2 of ΔpH_e as a gradient were established. DCA13 fermentation in a 15L fermenter with this strategy showed that DCA13 yield reached 145.2 g•L^-1 at 30℃ after 120 hours transformation,about 16% higher than those obtained in control batch fermentation by regulated pH at 7.8 throughout the production course. The suitable range of pH control in production phase is 7.5—8.2.

摘要： 利用热带假丝酵母（Candida tropicalis）突变株SP-UV-56进行十三碳二元酸发酵，研究了pH值控制模式对产酸的影响.低pH值对维持菌体活性有利，但不利于菌体产酸；高pH值能促进菌体产酸，但菌体活性有所下降.在研究中定义了3个参数pH_e值、C_p,e和ΔpH_e.菌体的产酸与ΔpH_e有关，通过实验建立了pH_e值与产酸量C_p,e之间的关联式，提出了pH值梯度控制策略，并确定了适宜的ΔpH_e.以ΔpH_e＝0.2为推动力，建立了pH值连续控制方程.应用pH值连续控制方程进行发酵，转化120 h产酸量达到145.2 g•L^-1，较对照组的产酸量提高了16％，适宜的pH值控制范围为7.5～8.2，为长链二元酸发酵技术实现pH值连续自动控制奠定了理论基础.