Enhanced Production of Bacterial Cellulose Production by Using Biofilm Reactor and its Material Property Analysis.

Abstract

Biofilm reactors show several advantages over suspended cell reactors, especially in their biomass density, operation convenience, and production yield. The structure of biofilm matrix contributes to high resistance of microorganisms to extreme conditions of pH, temperature, toxic chemicals, and mechanical shocks. Submerged fermentation has been used for BC production due to its feasibility of large-scale production in industry. The purpose of this research topic is to improve the rate of bacterial cellulose (BC) production by exploring new culture methods with a biofilm reactor. Biofilm reactor included a plastic composite support (PCS) which was attached on agitation shaft to promote effective nutrient delivery and to control biofilm thickness. BC harvested from PCS biofilm reactor was evaluated in terms of the physical and mechanical properties, including the degree of crystallinity and crystal size by x-ray diffraction (XRD), the water content and degradation characteristics using thermogravimetric analysis (TGA), nanostructure using field emission scanning electron microscopy (FESEM), and tensile strength using a dynamic mechanical analyzer (DMA). Among thirteen types of PCS, PCS blended with dried soybean hulls, defatted soybean flour, yeast extract, dried bovine red blood cells, and mineral salts (SFYR+) yielded the highest BC (7.05 g/l) which is 2.5 fold compared to control (2.82 g/l). The XRD studies indicated that crystallinity of BC pellicle is about 90%. FESEM image showed Acetobacter xylinum grew and produced BC on the PCS. TGA results showed that BC pellicle on the PCS had 95% water content. The results clearly demonstrated that implemented with PCS in agitated bioreactor can enhance BC production.