Investigating production, properties and applications of bacterial cellulose generated using coconut water as a substrate medium

Abstract

This study was carried out to investigate a promising application area of coconut water that is discharged in desiccated coconut industry as a waste. Bacterial cellulose (BC) is a highly hydrated, pure, extra-cellular product formed by bacterial species related to the genus Acetobacter. Production of BC using a substrate containing coconut water, was selected among available options. Due to its unique characteristics, BC has found applications in numerous fields like medical, food, paper, textile, electrical and electronic. A detailed study was performed to understand the production, properties and application potential of BC. A set of batch experiments was carried out in laboratory scale to observe the effect of process parameters on BC production in static fermentation. Experimental results revealed that area at air/liquid interface of the fermentor, initial sucrose content, initial NH4H2PO4 content, initial pH of the medium and the period of shaking at the initial stage of fermentation have a significant influence on BC yield. However, no significant effect was observed on BC yield when varying the volume of culture. Additionally, the batch experiment carried out in aerated fermentation resulted no visible BC production. A set of experiments performed using purified, fresh BC proved that BC has more than 80% (wet basis) water holding capacity. Furthermore, it was found that mechanical strength of BC can be enhanced using evaporation and vacuum drying methods more than freeze drying. Additionally, an increase in moisture absorbency was observed when decreasing the particle size of evaporation-dried BC due to increased surface area. Experiments that were carried out to find application areas revealed that BC has the potential of functioning as a wound dressing, an adsorbent and as a proton exchange membrane whereas the residual fermentation broth as a substrate for anolite in microbial fuel cells. Finally, finding membrane characteristics, developing BC as a wound dressing and improving BC yield and rate of production by eliminating limitations in static condition, were recommended as the areas that will be worthwhile for future work.