• Journal of Microbiology and Biotechnology
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• v.9 no.6
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• pp.704-708
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• 1999

In addition to catalyzing the synthesis of glucan from sucrose as a primary reaction, glucansucrase also catalyzes the transfer of glucose from sucrose to other carbohydrates that are present or are added to the reaction digest. Using dextransucrase and altemansucrase, prepared from Leuconostoc mesenteroides B-742CBM and B-1355C, respectively, we modified the bacterial cellulose in Acetobacter xylinum ATCC10821 culture, and then produced a characteristic cellulose that is soluble and has a new structure. There were also some partially modified insoluble cellulose and oligosaccharides in the modification culture. After methylation and following acid hydrolysis of both the soluble and insoluble glucans, there were ($1{\rightarrow}4$) as well as ($1{\rightarrow}6$) and ($1{\rightarrow}3$) glycosidic linkages in the soluble glucan.

• Journal of Microbiology and Biotechnology
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• v.14 no.6
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• pp.1200-1210
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• 2004

Metabolic flux analysis was established by adapting previous stoichiometric model developed during growth with cellulose to cell grown with cellobiose for further direct comparison of the bacterial metabolism. In carbon limitation with cellobiose, a shift from acetate-ethanol fermentation to ethanol-lactate fermentation is observed and the pyruvate overflow is much higher than with cellulose. In nitrogen limitation with cellobiose, the cellodextrin and exopolysaccharide overflows are much higher than on cellulose. In carbon and nitrogen saturation with cellobiose, the cellodextrin, exopolysaccharide, and free amino acids overflows reach the highest levels observed but all remain limited on cellulose. By completely shunting the cellulosome, the use of cellobiose allows to reach much higher carbon consumption rates which, in return, highlights the metabolic limitation of C. cellulolyticum. Therefore, the physical nature of the carbon source has a profound impact on the metabolism of C. cellulolyticum and most probably of other cellulolytic bacteria. For cellulolytic bacteria, the use of soluble carbon substrate must carefully be taken into consideration for the interpretation of results. Direct comparison of metabolic flux analysis from cellobiose and cellulose revealed the importance of cellulosome, phosphoglucomutase and pyruvate-ferredoxin oxidoreductase in the distribution of carbon flow in the central metabolism. In the light of these findings, future directions for improvement of cellulose catabolism by this bacterium are discussed.

• Journal of the Korean Wood Science and Technology
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• v.25 no.3
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• pp.83-95
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• 1997

The degradation mode of lignocellulose by anaerobic ruminal cellulolytic bacterium Ruminococcus albus F-40 was investigated. Birchwood holocellulose and filter paper were incubated as the sole carbohydrate sources with using the Hungate techniques. After 2 or 4 days of incubation, samples were employed for chemical and electron microscopic evaluations. The degradation rate of cellulosic substrates and the adhesion rate of bacteria to the substrates increased proportionally with the decrease of relative crystallinity of cellulose, indicating the preferential breakdown of amorphous cellulose, by this bacterium. X-ray diffraction analyses and polarized light microscopy showed, however, that crystalline cellulose was also degraded by R. albus. FT-IR spectra indicated that not only cellulose but hemicellulose was also degraded by this bacterium. Electron microscopic investigations showed the protuberant structures on the surface of R. albus. These structures were much more significant when bacterial cells were grown in the media containing insoluble substrates, such as cellulose, indicating clearly that bacterial protuberant structures were induced by the substrates. Protuberant structures extended from the bacterial cells adhered tightly to the substrates and numerous vesicles covered the surface of cellulosic substrates affected. Cellulosome-like structures were distributed on the cellulose matrix. Electron microscopic works showed that diverse surface organells of R. albus were involved in the degradation of cellulosic materials. SEM examinations showed the breakdown of cellulose by R. albus was proceeded by severeal routes : short fiber formation, defibrillation and destrafication of cellulose microfibril.

• Journal of Life Science
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• v.17 no.11
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• pp.1582-1586
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• 2007

Previous study (J. of Chem. Technol. Biotechnol. 2004, 79, 79-84) showed that bacterial cellulose (BC) produced by a bacterial strain JH232 has potential as a source for environmentally friendly ion exchange membranes. In this study, strain JH232 was investigated for phylogenetic classified and characterized for BC production. Comparative analysis of 16S rRNA gene revealed that the strain belongs to the genus Gluconacetobacter. Maximum production of BC was observed when JH232 was cultured in CSL medium (pH 5.5) at $30^{\circ}C$ as determined by flask experiment. When batch and fed-batch cultures of JH232 were performed in the fermenter experiment to compare BC productivity of the strain, BC productivity of fed-batch culture was 1.56 times higher than that of batch culture.

• Membrane Journal
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• v.31 no.6
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• pp.384-392
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• 2021

Growing pollution due to industrialization leads to difficulties in survival of mankind. Generation of clean water from wastewater by membrane separation process is emerging cost efficient technology. Membrane prepared from renewable resources are in lots of demand to reduce burden on synthetic polymers which is one of the source of environmental pollution. Bacterial cellulose (BC) is very pure and distinct form of cellulose nanofibrils (CNF). Nanopapers prepared from CNF are used ad ultrafiltration (UF) and nanofiltration (NF) membrane for different applications. High crystallinity of BC gives rise to excellent mechanical property, an essential criterion for wastewater treatment membrane. In this review, BC based membrane for application in dye, oil, heavy metal and chemical removal from wastewater is discussed.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.10a
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• pp.219-220
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• 2012

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.387-388
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• 2013

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.675-676
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• 2010

• KSBB Journal
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• v.18 no.2
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• pp.94-99
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• 2003

The effect of medium composition on the production of bacterial cellulose (BC) by Gluconacetobacter hansenii PJK was investigated. The addition of yeast extract and peptone in the medium increased the production yield (Y/sub p/s/) of BC. The amount of BC produced by G. hansenii PJK was constant if the initial pH of the medium was in the range 4.5 to 6.0. Strains from the supernatant of the culture medium produced more BC than those from inside the BC. BC production was dependent on glucose metabolism, and the addition of fructose or lactate as a carbon source converted cells to Cel/sup -/ mutants. Cel/sup -/ mutants produced by the addition of fructose or lactate to the medium caused 73% or 30% decreases in BC production, respectively. The addition of succinate, which is one of the constituents of the TCA cycle, did not affect the production of BC.

• Journal of Microbiology and Biotechnology
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• v.29 no.4
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• pp.617-624
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• 2019

Bacterial nanocellulose (BNC) which is generally synthesized by several species of bacteria has a wide variety of industrial uses, particularly in the food and material industries. However, the low levels of BNC production during the fermentation process should be overcome to reduce its production cost. Therefore, in this study, we screened and identified a new cellulose-producing bacterium, optimized production of the cellulose, and investigated the morphological properties of the cellulosic materials. Out of 147 bacterial isolates from ripened fruits and traditional vinegars, strain SFCB22-18 showed the highest capacity for BNC production and was identified as Komagataeibacter sp. based on 16S rRNA sequence analysis. During 6-week fermentation of the strain using an optimized medium containing 3.0% glucose, 2.5% yeast extract, 0.24% acetic acid, 0.27% $Na_2HPO_4$, and 0.5% ethanol at $30^{\circ}C$, about 5 g/l of cellulosic material was produced. Both imaging and IR analysis proved that the produced cellulose would be nanoscale bacterial cellulose.