• Biotechnology and Bioprocess Engineering:BBE
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• v.4 no.1
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• pp.41-45
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• 1999

Microbial cellulose has many potential applications due to its excellent physical properties. The production of cellulose from Acetobacter xylinum in submerged culture is, however, beset with numerous problems. The most difficult one has been the appearance of negative mutants under shaking culture conditions, which is deficient of cellulose producing ability. Thus genetic instability of Acetobacter xylinum under shaking culture condition made developing a stable mutant major research interest in recent years. To find a proper type of bioreactor for the production of microbial cellulose, several production systems were developed. Using a reactor system with planar type impeller with bottoms sparging system, it was possible to produce 5 g/L microbial cellulose without generating cellulose minus mutants, which is comparable to that of static culture system.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.40 no.3
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• pp.23-29
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• 2008

This study was performed to improve the printability of Hanji using a microbial cellulose from Saprolegnia ferax through investigating the printability of Hanji sized with the mixture of the microbial cellulose and various kinds of sizing agents. Conclusions obtained from the results of this study were as follows. The proper concentration of a microbial cellulose in sizing a printable Hanji with it was 0.5%. In general, there was no remarkable effect but some effect on the opacity and ink density. Hanji was sized with the mixture(5:5) of microbial cellulose(0.5%) and AKD(1.0%). As a result, ink spread was remarkably improved by the girth reduction of ink spot. There was remarkable effect because the mixture(5:5) of a microbial cellulose(0.5%) and CMC(1.0%) improved not only the gloss but also the density and girth of ink spot. Mixing(7:3) with corn starch(3.0%) showed the smallest girth of ink spot among applied sizing agents. Mixing(7:3) with PVA(5.0%) also showed some effect in the density and girth of ink spot.

• Microbiology and Biotechnology Letters
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• v.50 no.1
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• pp.122-125
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• 2022

The cellulose-fed microbial fuel cell (MFC) is a biotechnological process that directly converts lignocellulosic materials to electricity without combustion. In this study, the cellulose-fed, MFC-integrated thermophilic bacterium, Bacillus sp. WK21, with endoglucanase and exoglucanase activities of 1.25 ± 0.08 U/ml and 0.95 ± 0.02 U/ml, respectively, was used to generate electricity at high temperatures. Maximal current densities of 485, 420, and 472 mA/m² were achieved when carboxymethyl cellulose, avicel cellulose, and cellulose powder, respectively, were used as substrates. Their respective maximal power was 94.09, 70.56, and 89.30 mW/m³. This study demonstrates the value of the novel use of a cellulase-producing thermophilic bacterium as a biocatalyst for electricity generation in a cellulose-fed MFC.

• Journal of Life Science
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• v.11 no.1
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• pp.11-13
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• 2001

Several culture conditions affecting cellulose production by a newly isolated Acetobacter sp. A9 were examined by cultivating cells under shaking cultures. The inoculum size in the range of 1-10% (v/v) did not influence cellulose production. Maximum cellulose production was obtained with 200 rpm of agitation speed. The cells grown in the 75 ml of medium in a 250-ml conical flask produced the highest level of cellulose. The strain was able to produce cellulose at 25-3$0^{\circ}C$ with a maximum at 3$0^{\circ}C$. Cellulose production occurred at pH 4.5-7.5 with a maximum at pH6.5.

• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.5
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• pp.383-388
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• 2004

The conversion of a cellulose-producing cell ($Cel^+$) from Gluconacetobacter hansenii PJK (KCTC 10505 BP) to a non-cellulose-producing cell ($Cel^-$) was investigated by measuring the colony forming unit (CFU). This was achieved in a shaking flask with three slanted baffles, which exerted a strong shear stress. The addition of organic acid, such as glutamic acid and acetic acid, induced the conversion of microbial cells from a wild type to $Cel^-$ mutants in a flask culture. The supplementation of $1\%$ ethanol to the medium containing an organic acid depressed the con-version of the microbial cells to $Cel^-$ mutants in a conventional flask without slanted baffles. The addition of ethanol to the medium containing an organic acid; however, accelerated the conversion of microbial cells in the flask with slanted baffles. The $Cel^+$ cells from the agitated culture were not easily converted into $Cel^-$ mutants on the additions of organic acid and ethanol to a flask without Slanted baffles, but some portion of the $Cel^+$ cells were converted to $Cel^-$ mutants in a flask with slanted baffles. The conversion ratio of $Cel^+$ cells to $Cel^-$ mutants was strongly re-lated to the production of bacterial cellulose independently from the cell growth.

• KSBB Journal
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• v.11 no.5
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• pp.550-556
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• 1996

A complex medium was developed for the production of microbial cellulose by Acetobacter xylinum ATCC 23769. The optimum concentration of each nutrient for the production of microbial cellulose was determined to be 10g peptone, 20g yeast extract, 5g glucose, 1.56g Na2HPO4, 1.8g KH2PO4, 0.05g MgSO4, 0.002g FeCl3, 5g citric acid and 10 mL ethanol per liter. With synergistic effects of citric acid and ethanol, cellulose productivity achieved in developed medium was 0.446 gram of cellulose per gram glucose for static culture, which is much higher than reported values. Cell growth and the cellulose production in the developed medium under static culture was also investigated.

• Microbiology and Biotechnology Letters
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• v.28 no.3
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• pp.134-138
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• 2000

Extensive screening for cellulose-producing bacteria was done using differential media. Fifty seven strains were isolated totally from the fruits and the vinegar, respectively; the isolate A9 strain from apples was selected and examined to determine its taxonomical characteristics. The bacterium was identified as the genus Acetobacter sp_ based on morphological, cultural and biochemical properties. A9 strain produced acetic acid from ethanol and decomposed acetic acid to $CO_2$ and $H_2O$. They produced dihydroxyacetone from glycerol but did not produce y-pyrone from glucose and fructose. When A9 strain was cultivated statically in Hestrin and Schramm liquid medium(HS medium). thick cellulose pellicle was formed_ Higher cellulose production was obtained in the shaken culture using HS medium at 100 rpm.

• KSBB Journal
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• v.20 no.1 s.90
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• pp.50-54
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• 2005

Tar is often produced during the carbonization of cellulose that limits the formation fibrous structure of the carbonized sample. This problem was reduced by applying a high temperature $(up\;to\;800{\circ}C)$ during carbonization process. Alternatively, dry cellulose was immersed in toluene and ultrasonicated prior to carbonization. In both cases, complete fibrous structures were not achieved. The formation of tar was reduced by the heat treatment of cellulose in the presence of HCI vapor before carbonization process. Such treatment before carbonization yielded mostly the fibrous structures of the carbonized sample as evident from SEM analysis. Similar results were found when the cellulose was subjected to a heat treatment in an inert condition followed by the removal of tar by the oxidation process prior to the carbonization.

• The Korean Journal of Food And Nutrition
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• v.4 no.1
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• pp.99-107
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• 1991

Lignocellulose and lignolic compounds were absolutely given much weight In the biosphere, and their degradation was essential for continuous biological carbon circulation. Whereas aerobic cellulolytic microorganism dissolved the cellulose into their elements in the first stage, strict anaerobic cellulolytic microorganism's role was taken I increasing interest through the recent research. It was reviewed that anaerobic microbial degradation process of lignocellulose and its derivatives (cellulose, lignin, oligolignol and monoaromatic compound), and function of anaerobic microorganism on the. environmental ecology.

• Journal of Life Science
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• v.9 no.1
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• pp.69-80
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• 1999

Some trials to alter the structure of extracellular polysaccharides by means of biotransformation and microbial modification have been reported. Seaweed alginate was acetylated by intact and resting cells of Pseudomonas syringae ATCC 19304. Glucose analogs such as 3-O-methyl-D-glucose used as sole carbon sources was directly incorporated into curdlan by agrobacterium sp. ATCC 31749. The 2-amino-2-deoxy-D-glucose (glucosamine)and 2-acetamido-2-deoxy-D-glucose (N-acetylglucosamine) were incorporated into microbial cellulose by Acetobacter xylinum ATCC 10245. The changed monomeric composition in pullulan by Aureobasidium pullulans ATCC 42023 as well as zooglan by Zoogoea ramigera ATCC 25935 was another effect of glucose analogs used a carbon source. There was no effect of glucose analogs found in polysacharide-7 (PS-7) produced by Beijerinckia indica. ATCC 21423.