초록
Bacterial cellulose (BC) of insoluble extracellular polysaccharide can be produced by Gluconacetobacter strains. Because of its unique nano-structure, BC has found its applications in various fields. In this study, an intermittent feeding strategy was proposed for the static culture to produce BC film of arbitrary thickness in layer-by-layer form with high productivity. That is, simply by supplementing the nutrients directly to the top of BC film already formed, microorganisms would be able to utilize the oxygen and nutrients at the same time without any obstruction, thereby the production rate could be maintained at steady state. For example, the BC thickness was roughly 30mm in this modified static process after 30 days cultivation compared to 2mm in conventional static culture. Further, excessive amount of fresh medium addition would create a distance between the previous BC pellicle and the new air-liquid interface, thus resulting in a separated layer BC. For, example, once the distance is larger than some critical value (1mm in this study with ATCC 11142), there would be layer-by-layer BC pellicles formed. With concept of this intermittent feeding strategy, BC products can be produced with arbitrary shape and thickness continuously and with high productivity.