-
[show abstract]
[hide abstract]
ABSTRACT: Saccharomyces sp. SK0704 (further defined as SK0704) isolated from long-term-ripening kimchi was identified by a biochemical method with
an API kit; its physiology was found to be very similar to that of S. cerevisiae ATCC 26603 (further defined as ATCC 26603), except in terms of starch utilization. SK0704 did not excrete extracellular glucoamylase,
but utilized starch as a sole carbon source under only aerobic conditions. Crude enzyme excreted from SK0704 catalyzed the
saccharification of starch to glucose, but ATCC 26603 did not. The PCR product obtained using the chromosomal DNA of SK0704
and the primers designed on the basis of the extracellular glucoamylase-coding gene of S. diastaticus was homologous with the intracellular sporulation-specific glucoamylase of S. cerevisiae. SDS-PAGE pattern of soluble protein extracted from yeast cells grown on glucose was greatly different from that on starch.
From these results, we proposed that the SK0704 may have a specific physiological function for starch catabolism such as membrane
transport system and intracellular sac-charification of starch.
Biotechnology and Bioprocess Engineering 04/2012; 13(2):224-231. · 1.28 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: A nitrogen-fixing bacterium isolated from the root nodules of a cultivated leguminous plant, soybean (Glycine max L.), was cultivable and was identified as Rhizobium sp. Bacterial species isolated from root nodules of wild leguminous plants
including -bush clover, white dutch clover, wisteria, and false acacia were identified as Burkholderia cepacia, Pseudomonas migulae, Pseudomonas putida, and Flavobacterium sp, respectively, all of which are heterotrophic bacteria that grow in the rhizosphere. Temperature gradient gel electrophoresis
(TGGE) 16S-rDNA bands extracted directly from the bacterial population within the root nodules of the wild leguminous plants
were identified as Rhizobium sp, Mesorhizobium sp, and Bradyrhizobium sp. none were cultivable. Rhizobium sp. isolated from soybean root nodule generated approximately 48 and 19 mg/L of ammonium in glucose- and starch-defined medium,
respectively, during 8 days of growth. The growth rate of Rhizobium sp. was increased by the addition of yeast extract but not by the addition of ammonium. K
m
and V
max
for starch saccharification measured with the extracellular crude enzyme of Rhizobium sp. were 0.7556 mg/L and 0.1785 mg/L/min, respectively. The inoculation of Rhizobium sp. culture into a hydroponic soybean
plant culture activated root nodule development and soybean plant growth. The inoculated Rhizobium sp. survived for at least 4 weeks, based on the TGGE pattern of 16S-rDNA. The 16S-rDNA of Rhizobium sp. isolated from newly developed root nodules was homologous with the inoculated species.
Keywordsroot nodule-
Rhizobium sp-leguminous plant-nitrogen fixation-hydroponic culture-TGGE
Biotechnology and Bioprocess Engineering 04/2012; 15(5):716-724. · 1.28 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Dried glasswort was used as a raw material in the nuruk- and makgeolli-making process. The antioxidant, polyphenol, and total phenolic contents extracted from glasswort with 10% ethanol were 953
mM, 2,928 mg/kg, and 214 mg/kg, respectively. Saccharomyces cerevisiae generated 9.7 and 72.4 g/L of ethanol in glucose-defined medium without glasswort and 20 g/L of glasswort, respectively.
Nuruk was prepared from rice, wheat, and a rice-glasswort mixture. Approximately 93, 91, and 123 g/L of ethanol was produced in
the makgeolli fermented with rice nuruk (RN), wheat nuruk (WN), and rice-glasswort nuruk (RGN), respectively. Antioxidant, polyphenol, and total phenolic contents in the RGN-makgeolli were significantly higher than in the RN- and WN-makgeolli. The Fe, K, and Mg contents of the RGN-makgeolli were relatively higher than those of the RN- and WN-makgeolli. From these results, it may be suggested that the addition of glasswort to the nuruk-making culture enhanced yeast growth and improved nutritional quality of makgeolli.
Keywordsglasswort-
nuruk
-
makgeolli
-antioxidant-polyphenol
Food science and biotechnology 04/2012; 19(4):999-1004. · 0.49 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: A modified graphite felt electrode with neutral red (NRelectrode) was shown to catalyze the chemical oxidation of nitrite to nitrate under aerobic conditions. The electrochemically oxidized NR-electrode (EO-NR-electrode) and reduced NR-electrode (ER-NR-electrode) catalyzed the oxidation of 1,094+/-39 mg/l and 382+/-45 mg/l of nitrite, respectively, for 24 h. The electrically uncharged NRelectrode (EU-NR-electrode) catalyzed the oxidation of 345+/-47 mg/l of nitrite for 24 h. The aerobic bacterial community immobilized in the EO-NR-electrode did not oxidize ammonium to nitrite; however, the aerobic bacterial community immobilized in the ER-NR-electrode bioelectrochemically oxidized 1,412+/-39 mg/l of ammonium for 48 h. Meanwhile, the aerobic bacterial community immobilized on the EU-NR-electrode biochemically oxidized 449+/-22 mg/l of ammonium for 48 h. In the continuous culture system, the aerobic bacterial community immobilized on the ER-NR-electrode bioelectrochemically oxidized a minimal 1,337+/-38 mg/l to a maximal 1,480+/-38 mg/l of ammonium to nitrate, and the community immobilized on the EU-NR-electrode biochemically oxidized a minimal 327+/-23 mg/l to a maximal 412+/-26 mg/l of ammonium to nitrate every two days. The bacterial communities cultivated in the ER-NR-electrode and EU-NR-electrode in the continuous culture system were analyzed by TGGE on the 20th and 50th days of incubation. Some ammoniumoxidizing bacteria were enriched on the ER-NR-electrode, but not on the EU-NR-electrode.
Journal of Microbiology and Biotechnology 03/2010; 20(3):485-93. · 1.38 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: A noncompartmented microbial fuel cell (NCMFC) composed of a Mn(IV)-carbon plate and a Fe(III)-carbon plate was used for electricity generation from organic wastewater without consumption of external energy. The Fe(III)-carbon plate, coated with a porous ceramic membrane and a semipermeable cellulose acetate film, was used as a cathode, which substituted for the catholyte and cathode. The Mn(IV)-carbon plate was used as an anode without a membrane or film coating. A solar cell connected to the NCMFC activated electricity generation and bacterial consumption of organic matter contained in the wastewater. More than 99 degrees of the organic matter was biochemically oxidized during wastewater flow through the four NCMFC units. A predominant bacterium isolated from the anode surface in both the conventional and the solar cell-linked NCMFC was found to be more than 99 degrees similar to a Mn(II)-oxidizing bacterium and Burkeholderia sp., based on 16S rDNA sequence analysis. The isolate reacted electrochemically with the Mn(IV)-modified anode and produced electricity in the NCMFC. After 90 days of incubation, a bacterial species that was enriched on the Mn(IV)-modified anode surface in all of the NCMFC units was found to be very similar to the initially isolated predominant species by comparing 16S rDNA sequences.
Journal of Microbiology and Biotechnology 09/2009; 19(9):1019-27. · 1.38 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Weissella hellenica SKkimchi3 produces the higher exopolysaccharide (EPS) on sucrose than lactose, glucose, and fructose at pH 5 and 20 degrees C. Sucrose was exclusively used to cultivate SKkimchi3 in all experiments base on the EPS production tests. The molecular mass of EPS, as determined by gel permeation chroma-tography, was 203,000. (1)H and (13)C NMR analysis indicated that the identity of EPS may be a glucan. When EPS, starch, and cellulose was treated with a-amylase, glucoamylase, glucosidase, and cellulase, glucose was produced from starch and cellulose but was not produced from EPS. Based on HPLC analysis, elemental analysis, (1)H and (13)C NMR analysis, and enzymatic hydrolysis tests, EPS was estimated to be a glucan. EPS suspension was not precipitated even by centrifugation at 10,000xg for 60 min, and EPS made the fermented milk and bacterial culture viscous.
The Journal of Microbiology 11/2008; 46(5):535-41. · 1.10 Impact Factor
