Role of Ethanol in Improvement of Bacterial Cellulose Production: Analysis Using 13C-Labeled Carbon Sources

Abstract

We studied the role of ethanol in the improvement of bacterial cellulose (BC) production, primarily using 13C NMR. 13C-labeled BC was biosynthesized by Acetobacter xylinum ATCC 10245 using culture media containing D-(1-13C), (2-13C), and (6-13C)glucose. The introduction of (1-13C) ethanol was also investigated.Ethanol was not utilized as a carbon source for BC production, but was oxidized to acetic acid. The consumption rate of glucose and the extracellular conversion of glucose into gluconic acids were suppressed by the ethanol supplementation. The direct polymerization of the glucose into BC was accelerated; in contrast, the participation of the Entener-Doudoroff pathway was reduced by the ethanol supplementation. These results support the hypothesis that the improvement of BC production by ethanol supplementation can be achieved by the effective use of glucose. Ethanol could be used as a substitute for glucose and gluconic acids, and a source for metabolites in the tricarboxylic acid cycle.

The Effect of Carbon and Nitrogen Sources on Bacterial Cellulose Production and Properties from Gluconacetobacter sucrofermentans CECT 7291 Focused on its use in Degraded Paper Restoration

“…This study also suggests that ethanol acts not as a substrate for BC biosynthesis but as an energy source for ATP generation in the viable cells, increasing BC production as a result. Similar results have been found in studies with G. hansenii, (Park et al 2003) and with A. xylinum ATCC 10245 (Yunoki et al 2004). In the latter report, the authors suggest that ethanol was not the carbon source for BC production and that the improvement was a consequence of ethanol suppressing the transformation of glucose in gluconic acids, a process that potentiates a more efficient polymerization of glucose into BC.…”

“…7), the addition of ethanol to the media resulted in slightly lower figures. This effect has been reported previously by Park et al (2003) and by Yunoki et al (2004). Nevertheless, these authors found an increase in BC production in the presence of ethanol from the beginning of the test, whereas in this study's tests with the addition of 1% ethanol to the culture media BC production increased only in the last part of the assay in which YE+CSL was used as the nitrogen source (Fig.…”

“…In light of what has been discussed above, the increase in the production of BC achieved with the addition of ethanol to the YE+CSL medium can only be useful if bacterial cellulose is not generated directly on the document to be restored. Using A. xylinum ATCC 10245, Yunoki et al (2004) observed no differences in pH due to the presence of ethanol for 7 days. However, Park et al (2003) used G. hansenii and found a decrease in pH to 3 units on day 5.…”

“…As discussed in the Introduction, the addition of 1% ethanol has been shown to increase the production of BC (Yunoki et al 2004). Experiments were conducted to see whether this effect was significant for the bacterial strain and conditions.…”

Effect ofGluconacetobacter xylinuscultivation conditions on the selected properties of bacterial cellulose

“…However, based on the literature, changes in the pH value during the cellulose synthesis process may have a very complex character and thus it is diffi cult to clearly defi ne the cause of the changes in this parameter. As an example, Yunoki et al 28 did not observe any changes in the pH for seven days of cultivation of G. xylinus ATCC 10245. Park et al 29 who cultivated the strain of G. hansenii higher than its dry weight 31, 32 .…”