木薯粉同步糖化发酵(SSF)产丁二酸

Succinic acid fermentation by simultaneous saccharification and fermentation (SSF) with cassava flour

摘要:

【目的】通过优化产琥珀酸放线杆菌GXAS137同步糖化发酵木薯粉产丁二酸的发酵培养基，提高丁二酸产量，降低生产成本。【方法】在单因素试验的基础上，先利用Plackett-Burman试验设计筛选出影响丁二酸发酵的重要参数，再采用正交试验确定重要参数的最佳水平。【结果】价格低廉玉米浆可用作氮源，影响丁二酸产量的重要参数是木薯粉、玉米浆、碱式碳酸镁和糖化酶浓度。最佳条件为(g/L)：木薯粉100，玉米浆14，糖化酶2.0 AGU/g底物，碱式碳酸镁75。优化后丁二酸产量达到69.31 g/L，丁二酸得率为90.01%，生产强度为1.44 g/(L·h)。与初始条件(52.34 g/L)相比，丁二酸浓度提高了32.42%。并利用1.3 L发酵罐对SSF与SHF两种发酵工艺进行了比较，SSF丁二酸产量(72.21 g/L)远高于SHF (56.86 g/L)。【结论】产琥珀酸放线杆菌同步糖化发酵木薯粉丁二酸产量高，生产成本低，具有较好的工业化应用前景。

关键词:产琥珀酸放线杆菌，木薯粉，Plackett-Burman试验，正交试验，丁二酸

Abstract:

[Objective] In order to raising yields and reducing production costs, we optimized succinic acid production from Actinobacillus succinogenes GXAS137 by simultaneous saccharification and fermentation (SSF) with cassava flour as carbon source. [Methods] The important parameters were screened by the single factor experiment and Plackeet-Burman design. Then, the optimum values of the parameters were obtained by orthogonal experiment design. [Results] The results showed that corn steep liquor (CSL) was used as a proper nutrient in the succinic acid production from cassava flour. The optimum medium compositions were determined as (g/L): cassava flour 100, CSL 14, glucoamylase dose 2.0 AGU/g substrate and MgCO3 75. The succinic acid yield reached 69.31 g/L at the optimal condition. The conversion rate of cassava to succinic acid reached 90.01% and succinic acid productivity was 1.44 g/(L·h). The succinic acid content increased by 32.42% than that without the optimized condition (56.86 g/L). The simultaneous saccharification fermentation (SSF) and separated hydrolysis and fermentation (SHF) were compared with 1.3 L fermenter. The results showed that the succinic acid of SSF (72.21 g/L) was superior than SHF. [Conclusion] The high-level succinic acid production and low production cost from cassava flour may facilitate industrial scale application in future.

Key words:Actinobacillus succinogenes, Cassava flour, Plackett-Burman design, Orthogonal experiment design, Succinic acid