Monitoring the effect of pH on bacterial cellulose production and acetobacter xylinum 0416 growth in a Rotary Discs Reactor

Abstract

Bacterial cellulose demonstrates unique properties including high mechanical strength, crystallinity and water retention ability that are suitable for industrial applications, such as food, paper manufacturing and pharmaceutical. In this study, Acetobacter xylinum 0416 was cultured in a designed 10-L Rotary Discs Reactor (RDR) to produce bacterial cellulose. The effects of different pH in the range of 3.5–7.5 on the bacterial cellulose production and the bacterial growth were investigated. The highest yield was obtained at pH 5.0 with a total dried weight of 28.3 g, while the lowest yield was obtained at pH 3.5 with a total dried weight of 4.7 g. Results also showed that the dried weight of bacterial cellulose was 60% higher when the pH of the medium was controlled during the experiments compared with uncontrolled pH. In addition, A. xylinum 0416 growth decreased to around 30% when pH value dropped from 5.05 to 3.56. The results also proved that the formation of acetic acid as a by-product caused the pH to drop during fermentation process in 10-L RDR.