产琥珀酸放线杆菌利用甘薯粉产丁二酸发酵条件优化

Optimization of Succinic Acid Production from Sweet Potato Powder by Actinobacillus succinogenes

为了优化产琥珀酸放线杆菌(Actinobacillussuccinogenes)发酵甘薯粉生产丁二酸的发酵培养基,提高丁二酸产量,降低生产成本,本研究首先通过单因素实验对甘薯粉发酵产丁二酸的甘薯粉、MgCO_(3)、液化酶、糖化酶、氮源浓度和发酵时间进行了优化,再利用正交试验确定重要参数的最佳水平,最后利用2 L发酵罐对获得最佳发酵工艺进行放大实验。结果表明,混合氮源(酵母粉:玉米浆=1:2)可满足甘薯粉丁二酸发酵营养需求,影响丁二酸产量的重要参数是甘薯粉、MgCO_(3)、液化酶、糖化酶、混合氮源(酵母粉:玉米浆=1:2)的浓度。各因素最佳水平为:甘薯粉115 g/L、MgCO_(3)60 g/L,液化酶0.008 KUN-S/g底物,糖化酶3.09 AGU/g底物,混合氮源33 g/L。优化后丁二酸产量可达69.89 g/L,与优化前相比(42.46 g/L),丁二酸浓度提高了64.6%。2 L发酵罐发酵72 h,丁二酸可达71.42 g/L,丁二酸产率为79.87%,生产强度为0.99 g/(L·h)。因此,利用A.succinogenes发酵甘薯粉产丁二酸具有较好的工业化应用前景。

In order to raise yields and reduce production costs,the fermentation medium of succinic acid production by Actinobacillus succinogenes from sweet potato powder.First,the effects of sweet potato powder concentration,MgCO_(3) concentration,liquefaction enzyme dose,saccharifying enzyme dose,nitrogen source concentration and fermentation time on succinic acid production were investigated by single factor experiments in this study.Then,the optimum values of the parameters were obtained by orthogonal experiment design.Finally,the optimal fermentation conditions were amplified by 2 L stirred bioreactor.The results showed that mixed nitrogen source(yeast powder:corn steep liquor=1:2)was used as a proper nutrient in the succinic acid production from sweet potato powder.The formula optimization results showed that the important parameters were sweet potato powder,MgCO_(3),liquifying enzyme dose,glucoamylase dose and mixed nitrogen source.The optimum condition was as follows:Sweet potato powder 115 g/L,MgCO_(3)60 g/L,liquifying enzyme dose 0.008 KUN-S/g substrate,glucoamylase dose 3.09 AGU/g substrate,mixed nitrogen source 33 g/L.Succinic acid yield reached 69.89 g/L at the optimal condition,which was increased by 64.60% compared to that before optimization(42.46 g/L).Approximately 71.42 g/L of succinic acid content with a yield of 79.87% and a productivity of 0.99 g/(L·h)was obtained after 72 h in a 2 L bioreactor.Therefore,sweet potato powder could be a promising feedstock for the economical and efficient production of succinic acid through fermentation by A.succinogenes.