Production of butyric acid by immobilized cells in a fibrous-bed bioreactor of pilot-scale

In this paper,efficient production of butyric acid from glucose by Clostridum tyrobutyricum was performed with batch and fed-batch modes. Based on the results of 5-L fermentor's experiments,the fermentation process was successfully scaled up in a 5000-L fermentor. In 5-L fermentor batch modes,butyrate yield and productivity was reached to 0. 47 g / g and 0. 82 g / L·h respectively,which was improved by 31% and 134% compared with fermentations of free cells. In the fed-batch fermentation,the final concentration of butyric acid was 52. 8 g / L,increased by 46% compared to free-cell fermentation. From up-scaled fed-batch production of butyrate in the pilot plant,butyrate yield,productivity and butyrate concentration with immobilized-cells reached 0. 47 g / g,0. 63 g /( L·h) and 51. 63 g / L,which were improved by 37%,67% and 40% respectively. Results showed that compared with the laboratory scale,the fibrous bed reactor could maintain a higher level of butyric acid fermentation and the production efficiency when zoom up to 1000 times. The present work provides a powerful alternative to produce butyric acid as a bulk chemical in pilot scale.