• Microbiology and Biotechnology Letters
• /
• v.24 no.6
• /
• pp.726-732
• /
• 1996

To improve the fermentation characteristics(such as starch-degradability, ethanol tolerance, sugar and high-temperature tolerance) of recombinant haploid yeast Saccharomyces diastaticus K114, hybridization technique was used. The hybridization partner was S. diastaticus 1177 which had good glucoamylase activity and fermentabi- lity. The best hybrid HH64 showed improved ethanol tolerance, sugar and high-temperature tolerance. Especia- lly, the starch-fermentability was significantly improved, since the hybrid produced 1.60% (w/v) ethanol from 4% (w/v) starch, while the recombinant haploid K114 produced 1.30% (w/v) ethanol. The optimum temperature and pH for the starch-fermentation by the hybrid HH64 was 30$\circ$C and 5, respectively. The hybrid yeast HH64 produced 7.5% (w/v) ethanol directly from 20% (w/v) starch.

• Microbiology and Biotechnology Letters
• /
• v.22 no.6
• /
• pp.584-592
• /
• 1994

Several mutation procedures have been compared to obtain an ethanol-tolerant Saccha- romyces diastaticus strain secreting glucoamylase. These procedures include spontaneous mutation, EMS treatment, UV irradiation, and combination of EMS treatment and UV irradiation. All these methods were followed by adaptation of the yeast cells to gradually higher ethanol concentration. Among these procedures, the combined method of EMS treatment and UV irradiation gave the promising result, i.e. the ethanol tolerance of the yeast increased from 11.5%(v/v) to 14.0%(v/v). Respiratory deficient petite mutants of industrial and ethanol-tolerant yeast strains have been isola- ted and hybridized with haploid S. diastaticus strains. The resulting hybrids showed increased ethanol tolerance and starch-fermentability.

• Applied Biological Chemistry
• /
• v.3
• /
• pp.19-24
• /
• 1962

The results of re-examination for the isolates D-28, D-28a from Kimchi and 88-3 from laver are summarized as follows: 1). All these isolates were proved to be Gram positive, catalase positive and spore-forming. 2). While these strains were not consistent with Bacillus megaterium group with respect to Voges-Proskauer reaction and methyl red test, their cultural characteristics were well consistent with this group. 3). These isolates showed the similar suger-fermentability as B. megaterium group with a slight difference. 4). It is proved that, according to the forgoing results and vitamin $B_{12}$ producibility, the isolate 88-3 is identical with B. megaterium NRRL-B 938 and D-28, D-28a, with B. megaterium 425-1 and 425-2, respectively.

• Journal of the East Asian Society of Dietary Life
• /
• v.13 no.6
• /
• pp.593-600
• /
• 2003

This study was carried out in order to investigate the possibility of frozen rice batter for the manufacturing of Jeung-pyun. Despite of its unique taste and texture, Jeung-pyun is not consumed much because it needs long time to make. The physicochemical, sensory, rheological and surface characteristics of Jeung-pyun were analyzed to develop the easy manufacture method. The storage condition of rice batter was used at -2$0^{\circ}C$ up to 4 weeks. Statistical data analysis was completed using a SAS program. The results are summarized as follow: The pH brix% and sugar content of all samples which added low-temperature tolerance raw yeast or regular raw yeast decreased during the fermentation. Kind of yeast did not influence on the moisture content of the Jeung-pyun batter. Specific volume and carbon dioxide evolution of Jeung-pyun batter were highest when the rice batter was frozen for 1 week regardless of the kind of yeast. Overall quality of frozen batter of Jeung-pyim at -2$0^{\circ}C$ for 4 weeks had the highest score among different samples. As the test results of mechanical characteristics, cohesiveness, gumminess, brittleness, hardness and springiness did not show any significant differences statistically. The result clearly suggests that freezing the rice batter is a possibile way to manufacture Jeung-pyun.

• The Korea Journal of Herbology
• /
• v.25 no.4
• /
• pp.7-10
• /
• 2010

Objectives : The purpose of this study was to investigate the nodakenin and decursin contents in each fermented Angelicae gigantis Radix by 4 species of ferment strains. Methods : The strains of fermented Angelicae gigantis Radix were Lactobacillus plantarum(SE1), L. acidophilus(AC), Bacillus subtilis(B2) and B. licheniformis(BL2). The fermentative changes of nodakenin and decursin were analyzed using HPLC. Results : All of 4 species strains reduced nodakenin and decursin concentration in Angelicae gigantis Radix by fermentation. But fermentability were difference between strains. The nodakenin concentration of AC was lower than B2. The decursin concentrations of SE1 and AC were lower than B2 and BL2. Conclusions : 4 species of fermental strain were difference decomposable rate with nodakenin and decursin in fermented Angelicae gigantis Radix.

• Journal of Microbiology and Biotechnology
• /
• v.19 no.8
• /
• pp.845-850
• /
• 2009

Bioethanol derived from lignocellulosic biomass has the potential to replace gasoline. Cellulose is naturally recalcitrant to enzymatic attack, and it also surrounded by the matrix of xylan and lignin, which enhances the recalcitrance. Therefore, lignocellulosic materials must be pretreated to make the cellulose easily degraded into sugars and further fermented to ethanol. In this work, hydrothermal pretreatment on corn stover at $195^{\circ}C$ for 15 min with and without lower concentration of formic acid was compared in terms of sugar recoveries and ethanol fermentation. For pretreatment with formic acid, the overall glucan recovery was 89% and pretreatment without formic acid yielded the recovery of 94%. Compared with glucan, xylan was more sensitive to the pretreatment condition. The lowest xylan recovery of 55% was obtained after pretreatment with formic acid and the highest of 75% found following pretreatment without formic acid. Toxicity tests of liquor parts showed that there were no inhibitions found for both pretreatment conditions. After simultaneous saccharification and fermentation (SSF) of the pretreated corn stover with Baker's yeast, the highest ethanol yield of 76.5% of the theoretical was observed from corn stover pretreated at $195^{\circ}C$ for 15 min with formic acid.

• Journal of the East Asian Society of Dietary Life
• /
• v.18 no.1
• /
• pp.41-48
• /
• 2008

This study focused on the alcohol fermentability of traditional Nuruk, as well as yeast containing traditional Nuruk, in the production of Yakju. The fermentation performed with 30% Nuruk was effective with regard to alcohol yield. In addition, the fermentation containing 70% Nuruk showed the highest titratable acidity due to increased amounts of organic acids (succinic acid, oxalic acid, malic acid, acetic acid), which, however, negatively influenced the Yakju quality. Moreover, microbiological contamination always occurred in the fermentations using only Nuruk. In contrast, in the experiments with the yeast containing Nuruk, higher alcohol content and lower titrable acidity were obtained, independent of the Nuruk ratio used, positively effected the Yakju taste and flavor. Overall, the fermentation performed using the yeast containing 30% traditional Nuruk showed the best results for Yakju production.

• Korean Journal of Microbiology
• /
• v.16 no.3
• /
• pp.93-102
• /
• 1978

Saccharomyces cerevisiae strain M was cultured in a molasses-containing media with repeated transplantations of the yeasts from one culture to another to adapt to molasses. After that only different amounts of phosphorous and nitrogen sources were added to the media. And then some variations during the culture time and the effects of consituents of cell mass on the functional activity and sensitivity of the cell were investigated. The results obtained were summarized as follows : 1. In the same culture condition of yeasts, the carbohydrates and trehaloses contents were more remarkably increased when small amounts of phosphate and nitrogen sources were added, then when alrge amounts were added, but yield percentage on assimilated sugars was lower. 2. The content of trehalose in yeast cells was reduced remarkably at the early stage in the culture, but this increased remarkably at later stage. When small amounts of nitrogen and phosphate were added to the culture medium, the amount of thehalose in the cells increased greasly. 3. The more protein content was present in the yeast cells, the smaller the carbohydrate and trehalose content, but more amino-N, RNA and moisture content were present in the cells. And in this case fermentability of the cells was stronger, but sugar tolerance was lower. 4. During the preservation period of compressed yeast cells at different temperature, the higher the temperature was, the more rapidly the amount of trehalose in the cells decreased. And in the cell where the amount of trehalose in the cells decreased. And in the cell where the amount of trehalose(carbohydrate) was large and the amount of protein was small, the amount of trehalose decreased at a slower rate during the preservation period.

• Korean Journal of Microbiology
• /
• v.11 no.4
• /
• pp.157-166
• /
• 1973

Fermented feed using rice, barley, wheat, and defatted rice brans as the raw materials were prepared by 3 species of wild yeasts which were selected among 35 strains of yeasts isolated, and their analytical values were examined. The results were as follows : 1. The three yeasts were identified as H.amomala var. anomala (No.225), Candida utilis (No.400), and Irpex-cellulase(consors) (no.403-A). 2. The optimum pH, and sugar concentration of these yeasts in liquid culture were pH 5.0 and Bllg. 10.deg. each. The optimum temperature was 30.deg.C for No.225 and No.403-A, 25.deg.C for No.400. The No.225 and No.403-A grow at higher temperature than 37.deg.C and 40.deg.C each. 3. The No.225 yeast had a large vegetative cell and strong sugar fermentability. The No.225 and 403-A could assimilate cellobiose, xylose, $KNO_2$ and $KNO_3$. These properties were fit for bran fermentation. 4. The No.403-A microorganism was a yeast-like microbe and showed cellulase activity which might help the propagation of other yeasts on the brans. 5. The analytical data of fermented feed indicated the following order of usable value ; rice-wheat-barley bran 4:4:2, rice-wheat bran 5:5, rice-barley bran 5:5, rice-defatted rice bran 5:5. 6. the fermented feed were prepared by mixing brans, 0.3% ammonium sulfate and 5%(w/w) inoculum of yeast suspension in 4% glucose solution. Water content 70-80%, fermentation temperature 25-30.deg.C, and fermentation time 2-3 days were given. 7. The rice-wheat bran 5:5 and rice-barley bran 5:5 fermented feed showed 11, 17-11.45% protein increase, and the rice-barley-wheat bran 4:4:2 and rice-defatted bran 5:5 showed 3.75-6.03% protein increase. 8. The fermented feed prepared in this experiment by the author might work as a nutritive feed using microbial cell body, enzymes produced by microbes and other microbial cell constituents.

• Microbiology and Biotechnology Letters
• /
• v.16 no.3
• /
• pp.231-237
• /
• 1988

Several methods to produce ethanol from tapioca starch were examined. Among four methods tested, alcohol fermentation with extruded tapioca starch was the most effective, which alcohol yield was 460.5 f/ton. After 69hours reaction with Rhizopus sp. glucoamylase, 108.7mg/$m\ell$ of reducing sugar were produced from extruded tapioca and 43.8mg/$m\ell$ from raw tapioca starch. In alcohol fermentation with extruded tapioca, the high concentration of alcohol at early stage prevented bacterial contamination and the fermentation rate was increased due to the high saccharifying power of glucoamylase on the extruded starch, but extrusion temperature had no influence on the fermentability, Scanning electron microscopy showed that the extrusion process changed the structure of tapioca starch granule to more susceptible form to glucoamylase attack than the raw starch. And glucoamylase of Rhizopus sp. had stronger digestion activity on both extruded tapioca and raw tapioca starch than that of Aspergillus usamii.