Bacterial Cellulose Production by Gluconacetobacter xylinus
Date Issued
2010
Date
2010
Author(s)
Hsieh, Jung-Ting
Abstract
Bacterial cellulose (BC) is a kind of insoluble extracellular polysaccharide produced by Gluconacetobacter strains. Because of the unique properties, mainly the ultrafine reticulated structure, BC has found various applications in paper, textile, and food industries, and as a biomaterial in cosmetics and medicine. In this study, we investigated different cultural methods/conditions and medium composition to understand their influence on the BC production with Gluconacetobacter xylinus.
We found that the morphology of BC depends on the cultural methods and composition, and significant amount of medium might be entrapped inside the BC. If we do not remove that out of BC, the BC yield might be overestimated. Therefore, we suggest BC be cut into pieces to release the medium before treating with 0.5N NaOH at 90℃ for 30mins to release the rest of impurities.
When using BSH Medium (initial pH: 5.5) at 26°C under orbital shaking (100rpm), BC yield was 2.5g/L after 7 days cultivation. Therefore, we set it as a control group to discuss the effect of different environmental factors on the BC production. We tested BC yield for the initial pH ranging from 3.5 to 7.0, and found a maximum between pH 6.0 and 7.0 (3.5g/L). Besides, BC yield under orbital shaking (100rpm) is the highest compared with static cultivation and reciprocal shaking (100rpm).
To investigate the effect of carbon sources on the production of BC, various carbon sources were investigated at 2%(w/v). Good BC production was obtained when sucrose, glucose, fructose, or mannitol was used as the sole carbon source, and the highest yield was obtained with the sucrose (3.53g/L). Furthermore, BC yield would become higher with increasing glucose concentration, and the highest yield occurred at 8.0% (5.0g/L).
On the other hand, various nitrogen sources such as yeast extract, peptone, and corn steep liquor (CSL) were tested to assess their effects on BC production, and the highest cellulose yield was obtained for the case of 6.0% corn steep liquor (13.56 g/L), which was about four times higher than in BSH Medium.
Besides, other growth factors, such as ethanol, organic acid, and gluconic acid were also found to stimulate the BC production. For example, with 0.5% fumaric acid addition, the BC yield could increase from 2.5g/L to 7.0g/L.
Subjects
Bacterial cellulose
Type
thesis
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