• Journal of the Korean Wood Science and Technology
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• v.37 no.4
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• pp.397-405
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• 2009

In this study, we investigated the potential of producing bioethanol from Liriodendron tulipifera by using oxalic acid pretreatment. Amounts of fermentable sugars, mostly xylose and glucose, in the liquid fraction (hydrolysate) was $40.22g/{\ell}$ after the biomass was pretreated with 0.037 g/g of oxalic acid for 20 minutes at $160^{\circ}C$. Production amounts of ethanol was $8.6g/{\ell}$ from the 72 hours of simultaneous saccharification and fermentation (SSF) on solid fraction of the pretreated sample. At the same condition, when the reaction time increased to 40 minutes, $32.66g/{\ell}$ of fermentable sugars in the hydrolysate and $9.5g/{\ell}$ of ethanol was produced from the process of pretreatment and SSF. As a result of analyzing the fermentation inhibitors, such as acetic acid, 5-HMF, furfural and total phenolic compounds, as the reaction time increased, the amount of the fermentation inhibitors in the hydrolysate increased. Production of the fermentation inhibitors was more affected by initial concentration of oxalic acid rather than reaction time. $3.39{\sim}5.78g/{\ell}$ of acetic acid was produced by pretreatment with 0.013 g/g of oxalic acid, and the amount of furfural produced by decomposition of xylose was 2~3 times higher than the amount of 5-HMF produced by decomposition of glucose. All the hydrolysates contained more than $5g/{\ell}$ of total phenols considered as the degradation product of lignin. Therefore, by analyzing the amount of fermentable sugars and fermentation inhibitors in the hydrolysate, and producing ethanol from SSF of solid fraction of the pretreated sample, the biomass pretreated with 0.037 g/g of oxalic acid for 20 minutes at $160^{\circ}C$ can be expected to produce the most ethanol.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.5
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• pp.679-683
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• 2003

Strawberries were fermented for their effective value added product. In alcohol fermentation of strawberries, alcohol content was maximum value (9.22% ) under the condition of 16.32$^{\circ}$Brix of initial sugar concentration, 53.03 hr of fermentation time and 28.8$^{\circ}C$ of fermentation temperature. Acetic acid content revealed minimum value (0.49%) under the condition of 13.18$^{\circ}$Brix of initial sugar concentration, 50.99 hr of fermentation time and 24.96$^{\circ}C$ of fermentation temperature. Residual sugar content revealed minimum value (3.97$^{\circ}$Brix) under the condition of 15.00$^{\circ}$Brix, 52.00 hr and 26.0$0^{\circ}C$. The optimum conditions for each alcohol fermentation were 14$^{\circ}$Brix, 50 hr and 28$^{\circ}C$.

• Journal of Microbiology and Biotechnology
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• v.20 no.1
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• pp.110-116
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• 2010

Lactic acid (LA) fermentation by Lactobacillus salivarius ATCC 11741 immobilized on loofa sponge (LS) was evaluated. To increase the surface area of LS for cell immobilization, $H_2O_2$ and chitosan were introduced as surface modifying reagents. Four chitosans of different molecular weights were separately coated on LS. All experiments were conducted in shaking flask mode at 100 rpm rotating speed and $37^{\circ}C$ with 5% $CaCO_3$ as a pH regulating agent. The effects of initial glucose concentration were investigated in the range of 20-100 g/l on LA fermentation by free cells. The results indicate that the maximum concentration of LA was produced with 50 g/l glucose concentration. The immobilized cell system produced 1.5 times higher concentration than free cells for 24 h of fermentation. Moreover, immobilized cells can shorten the fermentation time by 2-fold compared with free cells at the same level of LA concentration. At 1% (w/v) chitosan in 2% (v/v) acetic acid, the Yp/s and productivities of various molecular weights of chitosans were insignificantly different. Repeated batch fermentations showed 5 effective recycles with Yp/s and productivity in the range of 0.55-0.85 and 0.90-1.20 g/l.h, respectively. It is evident that immobilization of L. salivarius onto LS permits reuse of the system under these fermentation conditions. Scanning electron micrographs indicated that there were more intact cells on the chitosan-treated LS than on the untreated LS, thus confirming the effectiveness of the LS-chitosan combination when being utilized as a promising immobilization carrier for LA fermentation.

• Journal of Hydrogen and New Energy
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• v.11 no.1
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• pp.29-41
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• 2000

Anaerobic fermentation using Clostridium butyricum NCIB 9576, and photo-fermentation using Rhodopseudomonas sphaeroides E15-1 were studied for the production of hydrogen from Makkoli, fruits (orange & apple, watermelon & melon) and Tofu wastewaters. From the Makkoli wastewater, which contained $0.94g/{\ell}$ sugars and $2.74g/{\ell}$ soluble starch, approximately $49mM\;H_2/{\ell}$ wastewater was produced during the initial 18h of the anaerobic fermentation with pH control between 6.5-7.0. Several organic acids such as butyric acid, acetic acid, propionic acid, lactic acid and ethanol were also produced. From Watemlelon and melon wastewater, which contained $43g/{\ell}$ sugars, generated about approximately $71mM\;H_2/{\ell}$ wastewater was produced during the initial 24 h of the anaerobic fermentation. Tofu wastewater, pH 6.5, containing $12.6g/{\ell}$ soluble starch and $0.74g/{\ell}$ sugars, generated about $30mM\;H_2/{\ell}$ wastewater, along with some organic acids, during the initial 24 h of anaerobic fermentation. Makkoli and Tofu wastewaters as substrates for the photo-fermentation by Rhodopseudomonas sphaeroides E15-1 produced approximately 37.9 and $22.2{\mu}M\;H_2/m{\ell}$ wastewaters, respectively for 9 days of incubation under the average of 9,000-10,000 lux illumination at the surface of reactor using tungsten halogen lamps. Orange and apple wastewater, which contained 93.4 g/l, produced approximately $13.1{\mu}M\;H_2/m{\ell}$ wastewater only for 2 days of photo-fermentation and the growth of Rhodopseudomonas sphaeroides E15-1 and hydrogen production were stopped.

• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.121-124
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• 2000

Organic acids were produced from wastes streams in food industries by cell-recycle fermentation using Propionibacterium acidipropionici ATCC 4965. As a results of continuous fermentation, maximum productivity was 3.32g organic acid/L/hr at the dilution rate of 0.2/hr. Compared to batch fermentation, maximum productivity was improved by as much as 13 times and cell mass production was increased by as much as 22 times. The diluted organic acids in the fermenter were selectively separated by liquid-liquid extraction using 30%(w/w) trioctylamine(TOA) dissolved in methylisobutylketone(MIBK). The degree of extraction was reached above 90% for both acetic and propionic acid through repeated extraction of organic acids in fermentation broth.

• KSBB Journal
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• v.8 no.5
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• pp.446-451
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• 1993

In ethanol fermentation, by-products such as glycerol, acetic acid and lactic acid are produced along with ethanol. The effects of culture conditions on cell growth ethanol production and by-products biosynthesis were investigated in ethanol fermentation using S. cerevisiae. With increasing aeration rate or yeast extract concentration, ethanol and by-products biosynthesis decreased while final cell mass increased. With increasing glucose concentration or decreasing temperature, final cell mass, ethanol and by-products concentrations all increased. The optimal pH for the cell growth, ethanol and by-products productions was found to be pH 4.5. By-products biosynthesis was found, in general, to proceed with the ethanol biosynthesis. The results can be applied for the optimization of ethanol fermentation and for the recovery and purification of ethanol from the culture broth.

• Journal of Life Science
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• v.6 no.1
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• pp.56-65
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• 1996

Black tea extractbsupplemented with 10% sucrose was fermented by fungus at 30$\circ$C. A pellicle thick as 7$\sim$8 mm covered entire surface of the medium and the wxtract converted to acidic beverage(abbreviated below as fermented black tea) by 14 days of fermentation. It was a kind of acetic acid fermentation depending on symbiotic microorganisms. During the fermentation strains of yeasts(Saccharomyces cerevisiae and Eeniella sp.)and bacteria(Bacillus subtilis, Kurthia zopfii, Gluconobacter oxydans and Deinicoccus sp.) were isolated from aqueous layer. Contrastly to it, a bacterial strain(Acetobacter aceti) was isolated from thick pellicle. The bacteria grew as a viscouse cluster on solid agar medium differently from usual strains of A. aceti. Fermented black tea had sweet-sour taste and sweet smell.

• 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.

• Journal of Microbiology and Biotechnology
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• v.3 no.2
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• pp.129-133
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• 1993

The effect of different compositions of organic acids on the flavor profile of 10% sugar solution was investigated by the response surface methodology, and the results were used to evaluate the flavor characteristics of lactic acid fermented cereal beverages. A mixture of extruded rice flour (10%) and soymilk (7.8% dry matter) was fermented with Leuconostoc mesenteroides (Sikhae). Depending on the substrate pretreatments, for example, the malt or amylase digestion and the proteolytic enzyme hydrolysis, the sugar and organic acid composition of the product varied. The organic acid composition of the fermented beverages was in the ranges of 0.44-0.55% lactic acid, 0.05-0.09% acetic acid and 0.07-0.09% citric acid, while that of commercial apple juice was 1.59% malic acid and 0.49% acetic acid. The flavor profiles of fermented beverages added with 10% sucrose were compared to those of apple juice and a model mixture containing 0.48% citric acid, 0.39% lactic acid and 0.12% acetic acid in 10% sugar solution. The QDA diagram of fermented beverages approached to that of apple juice, when the substrate was digested by amylase but not by protease.

• Korean Journal of Microbiology
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• v.31 no.2
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• pp.99-104
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• 1993

Two strains of the gram-negative acetic acid bacteria, Acetobacter sp. strain CS2- AND CS5, were isolated form the traditional raw rice wine vinegar of Haenam area. The strains oxidized ethanol to acetic acid and over-oxidized acetate and lactate to $CO^{2}$ and $H ^{2}$O. They produced 2-ketogluconic acid from glucose but did not produce .gamma.-pyrones from glucose and dihydroxyacetone from glycerol. The CS strains possessed ubiquinone-9 as a major isoprenoid quinone and contained straight-chain $C_{18 :1}$, $_C{16 : 0}$, and $C _{14 : 0}$ fatty acids. The DNA base composition of the CS2 and CS5 strains was 56.2 and 57.3 mole% G + C, respectively. The isolates were grown well on methanol, gluconate, erythritol, raffinose, dulcitol and xylitol as sole sources of carbon and energy which are different from those of other Acetobacter species and producedd acid from sucrose, glycerol, fructose, inositol, mannitol, and ribose.