• Food Science and Biotechnology
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• v.14 no.5
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• pp.576-580
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• 2005

Ten yeast strains affecting doenjang flavor were isolated from soybean fermented foods (traditional meju and doenjang), among which Zygosaccharomyces sp. Y-2-5, showing excellent growth, glucose consumption, pH, and flavor production, was selected. Higher alcohols produced by Zygosaccharomyces sp. Y-2-5 related to flavor were 2-propanol, 1-propanol, 2-methyl-1-propanol, 1-butanol, and 3.3-dimethyl-2-butanol. Optimal culture conditions for Zygosaccharomyces sp. Y-2-5 were 10% (w/v) NaCl, pH 4.0, 3.0% (w/v) glucose concentration, and inoculation time day 0 or 15 doenjang fermentation.

• The Korean Journal of Food And Nutrition
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• v.10 no.1
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• pp.97-101
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• 1997

Gas formation, and container swelling and explosion during the distribution of commercial soy sauce is an important problem to be solved. Six yeasts were isolated from soy sauce returned because of container swelling. Three isolates (SS-1, SS-2, SP-1) formed film on soy sauce while others did not. Five isolates(SS-1, SS-2, SS-4, SP-1, SP-2) actively fermented soy sauce to produce gas and all were identified as Zygosaccharomyces rouxii, and one other isolate (SS-3) fermented soy sauce very weakly and was identified as Candida globosa.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.5
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• pp.997-1002
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• 1999

The aim of the present study was to investigate effects of food preservative addition and changes in composition of herb extract product on the growth of spoilage yeast, Zygosaccharomyces sp. Herbs such as Panax ginseng, Cinnamomum cassia, Lycium chinense, Zyzyphus juiuba and Jingiber officinale were altogether put into water and essence was extracted at 80oC, and then the extract was concentrated at 75oC. The herb extract product was made by adding vitamins, amino acids and honey to the concentrated herb extract. The amount of gas produced from the herb extract product was increased as inoculated cell number increased but decreased as Brix concentration increased. Gases were produced in small amount when incubation was made at 4oC but large amounts of gases were produced at 25 or 40oC of incubation. The gas production and growth of Zygosaccharomyces sp. were measured after browning reaction was induced by heating at 85oC for 12 hours. It appeared that heating treatment did not induce any significant change in the gas production and growth of the cell. The effects of addition of various sugar to the herb extract produce were also invesigated. Amounts of gas production were in the order of glucose>sucrose>oligosaccharide>stevioside. The viable cell count was measured as 6.0$\times$107 CFU/g when glucose was added to the herb extract product. The viable cell counts were 5.0$\times$106, 3.0$\times$103, and 3.0$\times$102 CFU/g in sucrose, oligosaccharide and stevioside added herb extract product, respectively. The amount of gas production from the herb extract product was remarkably reduced by addition of such food preservatives as sodium benzoate and DF 100. TLC(thin layer chromatography) chromatogram of the herb extract showed stability of the herb extract in the above treatments.

• Fisheries and Aquatic Sciences
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• v.4 no.1
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• pp.10-17
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• 2001

One serious problem among the troubles to identify objects in an optical microscopic image is contour background due to non-uniform light source and various transparency of samples. To solve this problem, this paper proposed an elimination method of the contour background and compensation technique as follows. First, Otsu's optimal thresholding method extracts pixels representing background. Second, bilinear interpolation finds non-deterministic background pixels among the sampled pixels. Third, the 2D cubic fitting method composes surface function from pivoted background pixels. Fourth, reconstruction procedure makes a contour image from the surface function. Finally, elimination procedure subtracts the approximated background from the original image. To prove the effectiveness of the proposed algorithm, this algorithm is applied to the yeast Zygosaccharomyces rouxii and ammonia-oxidizing bacteria Acinetobacter sp. Labeling by this proposed method can remove some noise and is more exact than labeling by only Otsu's method. Futhermore, we show that it is more effective for the reduction of noise.

• Microbiology and Biotechnology Letters
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• v.24 no.4
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• pp.445-451
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• 1996

The strain YCH-37, which produces yeast cell wall lytlc enzyme, was isolated from soil. From the microscopic observation, morphological and cultural characteristics, this strain was identified to fungus, Dicyma sp. So, we named this strain as Dicyma sp. YCH-37. The lytic enzyme effectively lysed Salmonella typhimurium among intact living bacteria and Torulopsis, Hansenula, Zygosaccharomyces among intact living yeast, as well as autoclaved yeast strains. The yeast cell wall lytic enzyme was succesively purified to 204 folds with 13% yields through yeast glucan affinity adsorption and DEAE-cellulose column chromatography. The enzyme was identified to monomeric protein with molecular weight of 25,000 daltons from the results of SDS-PAGE and gel filtration. The optimum pH and temperature for the yeast lytic activity were 8.0 and 50$\circ$C, respectively. The enzyme was stable up to 40$\circ$C, and between pH 4.0-pH 10.0.

• Korean Journal of Microbiology
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• v.53 no.1
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• pp.39-48
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• 2017

In order to evaluate the diversity of microbial population of Korean traditional Deonjang and Gochujang produced in Jeju, Jeonnam, and Jeonbuk province area, microbial communities were analyzed using next generation sequencing. In this result, the dominant bacteria of Deonjang in three area were Bacillus amyloliquefaciens, Tetragenococcus halophilus, and Bacillus was major dominant bacteria in Jeonnam (43.16%) and Jeonbuk (64.54%) area. But in Jeju area, Bacillus was 0.22%, which was significantly different from the other two. Equally, the dominant fungi of Deonjang in 3 area were Candida versatilis. Common fungus in Jeonnam and Jeonbuk area was Candida sp., respectively, 64.22% and 33.68% and Micor sp. was a common fungus in Jeonnam (15.66%) and Jeonbuk area (36.73%). But in Jeju area, Candida sp. and Zygosaccharomyces rouxii were dominant than mold. Bacillus subtilis, Bacillus licheniformis, and B. amyloliquenfaciens were the preminant bacteria in the traditional Gochujang in three regions. But there were no common dominant fungi in the 3 regions. Aspergillus sp. and Rhizopus sp. prevailed in Jeju and Jeonnam region, and Zygosaccharomycess rouxii predominanted in Jeonbuk area. These results suggested that the difference in the samples collected for the study were classified into similar groups according to the characteristics of each sample rather than regional characteristics.

• Journal of Applied Biological Chemistry
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• v.52 no.2
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• pp.77-83
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• 2009

This study was conducted to investigate the effect of the fermentation broth of fruits and vegetables and various kinds of lactobacillus containing in the broth on anti-microbial activity, anti-acidity, its organic acid concentrations and deorderization. In addition, the quality of eggs laid from the hens supplemented with the fermentation broth was determined. The fermentation broth contained over 8 kinds of lactobacillus and other microbes. Lactobacillus (L.) hilgardii, L. reuteri, L. nagelii, L. plantarum, and Zygosaccharomyces bisporus were survived especially in pH 2.0 among them. The concentrations of acetic acid and lactic acid in the broth were higher than minimum inhibitory concentration values (MIC) to Escherichia (E.) coli and Salmonella sp. Overall the broth contained sufficient organic acid to inhibit the growth of E. coli and Salmonella sp. In addition, L. nagelii and L. plantarum had the greatest anti-microbial activity against E. coli, Salmonella (S.) typhimurium, Staphylococcus aureus and S. gallinarium among lactobacillus in the broth. The broth had greater anti-microbial activity than individual lactobacillus. The fermentation broth had deodorization capacity of ammonia and hydrogen sulfate and the 50% of their concentrations were removed after 30 min treatment. Egg production rates, egg weight, and feed efficiency were increased in eggs laid from hens that supplemented with 0.1 % fermented broth compared to the control. The supplementation also increased the thickness and strength of egg shell to reduce broken eggs and decreased cholesterol levels in egg yolk. In conclusion, the fermentation broth of fruits and vegetables can be a natural alternative supplementation of feed in laying hens.

• Journal of Microbiology and Biotechnology
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• v.27 no.4
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• pp.678-684
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• 2017

The aim of this study was to elucidate the changes in the microbial community and biochemical properties of a traditional sweet paste during fermentation. PCR-denaturing gradient gel electrophoresis (DGGE) analysis showed that Aspergillus oryzae was the predominant species in the koji (the fungal mixture), and the majority of the fungi isolated belonged to two Zygosaccharomyces species in the mash. The bacterial DGGE profiles revealed the presence of Bacillus subtilis during fermentation, and Lactobacillus acidipiscis, Lactobacillus pubuzihii, Lactobacillus sp., Staphylococcus kloosi, and several uncultured bacteria were also detected in the mash after 14 days of main fermentation. Additionally, during main fermentation, amino-type nitrogen and total acid increased gradually to a maximum of $6.77{\pm}0.25g/kg$ and $19.10{\pm}0.58g/kg$ (30 days) respectively, and the concentration of reducing sugar increased to $337.41{\pm}3.99g/kg$ (7 days). The 180-day fermented sweet paste contained $261.46{\pm}19.49g/kg$ reducing sugar and its pH value remained at around 4.65. This study has used the PCR-DGGE technique to demonstrate the microbial community (including bacteria and fungi) in sweet paste and provides useful information (biochemical properties) about the assessment of the quality of sweet paste throughout fermentation.