Team:TUST China/Design

Team:TUST China 2017

Project Design

  • How to Improve the Yield of Bacterial Cellulose(BC)?

    We refine the fermentation condition to improve the yield of BC.Based on related literature, we found out that pH is an significant element influencing the yield of BC. Therefore, we set up culture media with different initial pH and phosphoric acid solution as buffer. After measure the parameters of pH, residue sugar and the yield of BC after 10days of fermentation. We confirm the optimal pH for the fermentation of G. xylinus is around 5.

  • How to Stabilize the pH during Fermentation?

    We have tried to express an alkaline producing gene in G. xylinus,but the growth of G.xylinus is poor. Therefore, we introduce E. coli to produce alkaline for G. xylinus. We have located a alkaline-producing gene called glsA and verified it in E.coli. In order to maintain the pH at 5, we found a part pASR and used it as the promoter of glsA. After verification, the data proves that our modified E. coli is capable of stabilizing the pH in the culture media at 5.

  • How to co-cuture G. xylinus and E. coli?

    The growth conditions and incubation time for these two strains is very different.However, we can still determine an fermentation conditions,a formula of culture media, the inoculum amounts, and synergistic factors for these two strains with the sole purpose of a higher yield of BC. We conducted experiments to determine the optimal formula of culture media and inoculum amounts via response surface method(RSM)

  • Is there another way to improve the yield?

    After establishing the co-culture system of E. coli and G. xylinus, the yield of BC has been improved. However, we still want to take a step further. Thus we choose to work on G. xylinus by overexpressing some key genes involved in producing BC and switched different promoters. When we co-culture the modified G. xylinus with E. coli, we notice a significant yield rise of BC.

  • What are the applications

    We have conducted tests on the properties of BC including doing Scanning Electron Microscopy (SEM) and Infrared Spectroscopy (FTIR). We figure whether it is possible for our lab-produced BC to be applied in real-world industrial manufacturing. Therefore, we visited Shandong Nameide Biotechnology Co., Ltd and asked them to do a quality check on our product. The result is positive and they pointed out the greatest potential of our product is wound dressing material.