十三碳二元酸发酵过程中的pH值梯度控制

CONTROL OF pH GRADIENT FOR 1,13-TRIDECANEDIOIC ACID FERMATATION

利用热带假丝酵母 (Candidatropicalis)突变株SP UV 5 6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 pHe 值、Cp ,e和ΔpHe 菌体的产酸与ΔpHe 有关 ,通过实验建立了 pHe 值与产酸量Cp,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ΔpHe 以ΔpHe=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 12 0h产酸量达到 14 5 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

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 was 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 15 L 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.