纤维床固定化酪丁酸梭菌发酵木薯渣水解液生产丁酸的研究

Production of the Butyric Acid from Cassava Residue Hydrolysate with Clostridium tyrobutyricum in Fibrous-bed Bioreactor

[目的]研究纤维床固定化酪丁酸梭菌发酵木薯渣水解液生产丁酸的可行性。[方法]以酪丁酸梭菌为生产菌株,初步优化了木薯渣的水解条件,并开展了纤维床固定化生物反应器半连续发酵木薯渣水解液生产丁酸的研究。[结果]加压条件下,稀酸水解木薯渣的总还原糖得率达到0.56 g/g。酪丁酸梭菌能有效利用葡萄糖、木糖进行单糖或混合糖发酵生产丁酸;固定化补料流加发酵有利于提高丁酸的产量和得率,降低副产物乙酸的产量和得率;以木薯渣水解液用于固定化批次发酵生产丁酸时,丁酸的产量和得率均较高,分别为(23.20±1.32)g/L和(0.44±0.01)g/g。[结论]木薯渣水解液对丁酸生产菌的生长和代谢没有明显的抑制作用,发酵各参数指标均能达到利用葡萄糖时的同等水平,可作为未来微生物发酵工业化生产丁酸的廉价原料来源。

[Objective] The research aimed to study feasibility for production of the butyric acid from cassava residue hydrolysate by C.tyrobutyricum immobilized in fibrous-bed bioreactor（FBB）.[Method] C.tyrobutyricum as producing strain,production of the butyric acid from cassava residue hydrolysate by fibrous-bed bioreactor was studied,as well as optimization for hydrolysis condition of the cassava residue.[Result] At high pressure,yield for total reducing sugar of the cassava residue hydrolyzed by dilute HCl was 0.56 g/g.Glucose and xylose could be well utilized by C.tyrobutyricum to produce butyric acid.The fed-batch immobilized fermentation mode has been successfully used to produce more butyric acid with higher final concentration and yield when compared with the free-cell fermentation mode,together with lower acetic acid output.The fermentation reached a maximum butyric acid concentration of（23.20±1.32） g/L and a yield of（0.44±0.01） g/g from cassava residue hydrolysate in batch FBB mode.[Conclusion] Cassava residue hydrolysate had no inhibition effects on growth and metabolism of the C.tyrobutyricum,and fermentation level was closed to the condition when glucose was chosen as carbon source,which could be expected to be ideal cheap material source for industrialized bioproduction of the butyric acid in the future.