Monitoring Production of Bacterial Cellulose by Acetobacter xylinum 0416 with Fuzzy Logic via Simulation

Bacterial cellulose (BC) is a unique biopolymer with high mechanical strength, crystallinity, purity and biocompatibility which make it suitable in various fields. An economical and high quantity production in industrial scale has become a concern in BC production. This study emphasizes on the usage of matured coconut water, an agro waste as the fermentation medium of bacterial cellulose synthesis by Acetobacter xylinum 0416. A central composite design was employed to predict the optimum production of BC based on a combination of three parameters that are initial pH, temperature and inoculum size. To stimulate and improve the performance in fermentation, a fuzzy logic system was designed. The controlled variables are pH and temperature whereas flowrate of cooling water and acid or alkaline flowrate are the manipulated variables respectively. The temperature of 32◦ C, pH 4.5 and 15% of inoculum size were found as the optimum condition to achieve a maximum dry weight of BC in this fermentation. The optimal value of pH is the set point for pH (4.5) and temperature (32◦ C). For the size of inoculum, it is considered constant for the control method of fuzzy logic. The results show that control and monitoring of pH and temperature reached set point as well as ability to maintain the set point after the introduction of disturbance for pH from 4.5 to 4.3 and temperature from the 32◦ C to 30◦ C. This shows the effectiveness of the control system by using fuzzy logic.