Presentation Information
[P04-478]Enhancement of Bacterial Cellulose Production by Increasing Gas–Liquid Contact Area Using an Oxygen-Permeable Film Culture Bag
○Ai Tanaka1,2, Yukino Kobayashi2, Toshihiro Suzuki3, Morio Ishikawa3, Masatoshi Kubota1, Takanori Nihira1, Satoshi Takesono1, Masayuki Onodera1,2 (1. Niigata Institute of Technology (Japan), 2. Niigata Prefecture Microbiological Society (Japan), 3. Tokyo University of Agriculture (Japan))
Keywords:
Bacterial cellulose,Oxygen-permeable film,Static cultivation,Gas–liquid contact area,Komagataeibacter nataicola
[Purpose]
Bacterial cellulose (BC) is a unique biomaterial composed of β-1,4-linked glucose, sharing the same fundamental chemical structure as plant cellulose. However, BC forms an ultrafine nanofiber network with fiber diameters of approximately 20–50 nm, which is significantly smaller than that of plant cellulose. This highly entangled three-dimensional network structure imparts remarkable properties such as high water retention capacity, excellent mechanical strength, superior biocompatibility, and biodegradability. Due to these properties, BC has attracted attention for applications in functional food materials, biomedical materials such as wound dressings and tissue scaffolds, and industrial materials such as acoustic diaphragms and high-quality paper. Despite these advantages, the high production cost of BC remains a major limitation for industrial application. Therefore, the development of a simple and cost-effective cultivation method is required. In this study, we evaluated a novel static cultivation method using an oxygen-permeable film culture bag as a potential low-cost BC production system.
[Method]
Komagataeibacter nataicola NRIC 0616 was used as a BC-producing strain and cultivated statically at 30°C for 7 days in Hestrin–Schramm (HS) medium. BC production was compared between a conventional Erlenmeyer flask and an oxygen-permeable film culture bag under identical conditions. After cultivation, BC pellicles were collected and purified by immersion in 1 mol/L NaOH solution to remove bacterial cells and impurities. The samples were thoroughly washed with running water, soaked in distilled water to remove residual alkali, and dried at 110°C to constant weight for quantification.
[Results]
The BC yield obtained in the flask culture was 0.64 g/L, whereas that in the film culture bag reached 0.808 g/L. Thus, BC production in the film bag system was approximately 1.25 times higher than that in the flask culture under the same conditions.
[Consideration]
In general, the oxygen transfer rate is higher in flask cultures; however, gas–liquid contact is limited to the liquid surface, resulting in a relatively small contact area. In contrast, the oxygen-permeable film culture bag provides a larger gas–liquid contact area over the entire culture surface. Although the oxygen transfer rate per unit area may be lower, the increased contact area likely enhances overall oxygen supply. Since BC production is strongly dependent on oxygen availability, this improved oxygen supply is considered to contribute to the increased BC production observed in the film bag system.
[Conclusion]
The oxygen-permeable film culture bag is a promising cultivation system for improving BC production. This method enhances oxygen supply through increased gas–liquid contact area and achieves higher BC yields than conventional flask culture. It also has potential as a simple and cost-effective approach for industrial BC production.
Bacterial cellulose (BC) is a unique biomaterial composed of β-1,4-linked glucose, sharing the same fundamental chemical structure as plant cellulose. However, BC forms an ultrafine nanofiber network with fiber diameters of approximately 20–50 nm, which is significantly smaller than that of plant cellulose. This highly entangled three-dimensional network structure imparts remarkable properties such as high water retention capacity, excellent mechanical strength, superior biocompatibility, and biodegradability. Due to these properties, BC has attracted attention for applications in functional food materials, biomedical materials such as wound dressings and tissue scaffolds, and industrial materials such as acoustic diaphragms and high-quality paper. Despite these advantages, the high production cost of BC remains a major limitation for industrial application. Therefore, the development of a simple and cost-effective cultivation method is required. In this study, we evaluated a novel static cultivation method using an oxygen-permeable film culture bag as a potential low-cost BC production system.
[Method]
Komagataeibacter nataicola NRIC 0616 was used as a BC-producing strain and cultivated statically at 30°C for 7 days in Hestrin–Schramm (HS) medium. BC production was compared between a conventional Erlenmeyer flask and an oxygen-permeable film culture bag under identical conditions. After cultivation, BC pellicles were collected and purified by immersion in 1 mol/L NaOH solution to remove bacterial cells and impurities. The samples were thoroughly washed with running water, soaked in distilled water to remove residual alkali, and dried at 110°C to constant weight for quantification.
[Results]
The BC yield obtained in the flask culture was 0.64 g/L, whereas that in the film culture bag reached 0.808 g/L. Thus, BC production in the film bag system was approximately 1.25 times higher than that in the flask culture under the same conditions.
[Consideration]
In general, the oxygen transfer rate is higher in flask cultures; however, gas–liquid contact is limited to the liquid surface, resulting in a relatively small contact area. In contrast, the oxygen-permeable film culture bag provides a larger gas–liquid contact area over the entire culture surface. Although the oxygen transfer rate per unit area may be lower, the increased contact area likely enhances overall oxygen supply. Since BC production is strongly dependent on oxygen availability, this improved oxygen supply is considered to contribute to the increased BC production observed in the film bag system.
[Conclusion]
The oxygen-permeable film culture bag is a promising cultivation system for improving BC production. This method enhances oxygen supply through increased gas–liquid contact area and achieves higher BC yields than conventional flask culture. It also has potential as a simple and cost-effective approach for industrial BC production.
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