• Food Science of Animal Resources
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• v.27 no.3
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• pp.363-370
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• 2007

In order to identify probiotic microorganisms, 25 isolates of Lactobacillus sp. were selected from kimchi based on their growth rates, lactic acid production and salt tolerance. The isolate JK-01 was identified as Lactobacillus plantarum by the API kit and 16S rDNA analysis (99.9% of homology), and named as L. plantarum JK-01. The maximum number of L. plantarum JK-01 was reached at 18 hr fermentation in MRS broth and the pH gradually decreased to 4.5. L. plantarum JK-01 showed high enzyme activities for xylanase, amylase, protease, and phytase on MRS agar plates containing each substrate. L. plantarum JK-01 showed high resistance to acidic pH and bile salts, and grew well even at pH 2.0 and 1.0% bile salt. In particular, L. plantarum JK-01 showed high heat stability as shown by $3.3{\times}10^3$ CFU/mL at $60^{\circ}C$. The isolate showed remarkable antimicrobial activity against E. coli in MRS broth based on its disappearance after 18 hr and clear zone formation using a paper disk assay. These results suggest that L. plantarum JK-01 may be probiotic in nature.

• Journal of Animal Science and Technology
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• v.48 no.2
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• pp.307-314
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• 2006

To search direct fed microbials, we isolated a Candida sp. from kefir grain. The isolated Candida sp. strain showed 99.8% of identity to the species of Candida kefyr by API 20C kit. Enzyme activity of Candida kefyr was higher in amylase (0.33±1.12μmol/min/mg) than that in phytase (0.052±0.98μmol/ min/mg) cellulase(0.051±μmol/min/mg) and xylanase (0.011±0.98mol/min/mg). The maximum numbers of Candida kefyr in growth curve were reached at 30 h fermentation. Candida kefyr showed high resistances to acidic environment, which was not perfectly extincted even at pH 2.0. And it showed high tolerance to bile salt which had almost 97.2% of survival in the presence of 1.0% bile salt.Especially, Candida kefyr showed high heat stability which remained 10% of initial microorganisms at 60℃. Candida kefyr was not generally inhibited by most of 11 antibiotic agent which contained tetracycline groups. These results suggest that the isolated Candida kefyr has a useful properties as probiotics.

• Mycobiology
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• v.34 no.4
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• pp.159-165
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• 2006

One of the most economically viable processes for the bioconversion of many lignocellulosic waste is represented by white rot fungi. Phanerochaete chrysosporium is one of the important commercially cultivated fungi which exhibit varying abilities to utilize different lignocellulosic as growth substrate. Examination of the lignocellulolytic enzyme profiles of the two organisms Phanerochaete chrysosporium and Rhizopus stolonifer show this diversity to be reflected in qualitative variation in the major enzymatic determinants (ie cellulase, xylanase, ligninase and etc) required for substrate bioconversion. For example P. chrysosporium which is cultivated on highly lignified substrates such as wood (or) sawdust, produces two extracellular enzymes which have associated with lignin deploymerization. (Mn peroxidase and lignin peroxidase). Conversely Rhizopus stolonifer which prefers high cellulose and low lignin containg substrates produce a family of cellulolytic enzymes including at least cellobiohydrolases and ${\beta}-glucosidases$, but very low level of recognized lignin degrading enzymes.

• Journal of Microbiology and Biotechnology
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• v.19 no.6
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• pp.573-581
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• 2009

The complex enzyme pool secreted by the phytopathogenic fungus Fusarium graminearum in response to glucose or hop cell wall material as sole carbon sources was analyzed. The biochemical characterization of the enzymes present in the supernatant of fungal cultures in the glucose medium revealed only 5 different glycosyl hydrolase activities; by contrast, when analyzing cultures in the cell wall medium, 17 different activities were detected. This dramatic increase reflects the adaptation of the fungus by the synthesis of enzymes targeting all layers of the cell wall. When the enzymes secreted in the presence of plant cell wall were used to hydrolyze pretreated crude plant material, high levels of monosaccharides were measured with yields approaching 50% of total sugars released by an acid hydrolysis process. This report is the first biochemical characterization of numerous cellulases, hemicellulases, and pectinases secreted by F. graminearum and demonstrates the usefulness of the described protein cocktail for efficient enzymatic degradation of plant cell wall.

• Journal of Mushroom
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• v.15 no.3
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• pp.134-138
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• 2017

The white button mushroom, Agaricus bisporus, is commercially the fifth most important edible mushroom, accounting for the production of 9,732 tons of mushrooms in Korea in 2015. The genus Agaricus has been known for its potential to degrade lignocellulosic materials. Chemical analyses carried out during the cultivation of A. bisporus indicated that the cellulose, hemicellulose, and lignin fractions were changed preferentially for both vegetative growth and sexual reproduction. We screened A. bisporus strains for effective biodegradation through extracellular enzyme activity using cellulase, xylanase, and ligninolytic enzymes. The enzyme biodegradations were conducted as follows: mycelia of collected strains were incubated in 0.5% CMC-MMP (malt-mops-peptone), 0.5 Xylan-MMP, and 0.5% lignin-MMP media for 14 days. Incubated mycelia were stained with 0.2% trypan blue. Eighteen strains were divided into 8 groups based on different extracellular enzyme activity in MMP media. These strains were then incubated in sterilized compost and compost media for 20 days to identify correlations between mycelial growth in compost media and extracellular enzyme activity. In this study, the coefficient of determination was the highest between mycelial growth in compost media and ligninolytic enzyme activity. It is suggested that comparison with ligninolytic enzyme activity of the tested strains is a simple method of screening for rapid mycelial growth in compost to select good mother strains for the breeding of A. bisporus.

• The Korean Journal of Mycology
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• v.40 no.3
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• pp.152-158
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• 2012

The lignocellulytic enzymes including a-amylase (EC 3.2.1.1), lignin peroxidase (EC 1.11.1.14), laccase (EC 1.10.3.2), xylanase (EC 3.2.1.8), ${\beta}$-xylosidase (EC 3.2.1.37), ${\beta}$-glucosidase (EC 3.2.1.21) and cellulase (EC 3.2.1.4) were extracted from spent mushroom compost (SMC) of Pleurotus eryngii. Different extraction buffers and conditions were tested for optimal recovery of the enzymes. The optimum extraction was shaking incubation (200 rpm) for 2 h at $4^{\circ}C$. ${\alpha}$-Amylase was extracted with the productivity range from 1.20 to 1.6 Unit/SMC g. Cellulase was recovered with the productivity range from 2.10 to 2.80 U/gf. ${\beta}$-glucosidase and ${\beta}$-xylosidase productivities showed lowest recovery producing 0.1 U/g and 0.02 U/g, respectively. The P. eryngii SMCs collected from three different mushroom farms showed different recovery on laccase and xylanse, cellulase. Furthermore, the water extracted SMC was compared to commercial enzymes for its industrial application in decolorization and cellulase activity.

• Korean Journal of Microbiology
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• v.29 no.1
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• pp.8-15
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• 1991

Interspecific hybrids between the ASpergillus spp., A. awamori, A. usamii and A. oryzae, were obtained by nuclear transfer technique. Nuclei isolated from an auxotrophic mutant strain were transferred into the protoplasts of a recipient strain of different species. The frequency of interspecific hybrid formation by nuclear transfer was $2*10^{-5}$ $-7*10^{-4}$ In contrast, no interspecific hybrid was isolated by protoplast fusion. Among the hybrids tested, 10 strains showed increased activity of some or all components of cellulases, xylanases and amylase up to more than two times. Isozyme pattern of the hybrids were analyzed by polyacrylamide gel electrophoresis and isoelectric focusing followed by activity staining, which showed that some of the hybrids have isozyme patterns unidentical to either of the two parents. By measuring the DNA contents and the sizes ofthe conidia, the karyotypes of the hybrids were estimated to be aneuploid near to haploid, diploid or triploid. It was concluded that the unclear transfer technique is much more efficient in the formation of interspecific hybrids than protoplast fusion and is very useful for the improvement of Aspergillus strains.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.10a
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• pp.199.1-199
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• 2003

제주민속주인 좁쌀약주의 제조를 위하여 전국에서 수집된 35종의 누룩으로부터 우수 곰팡이와 효모를 분리하였다. 수집된 누룩의 균수는 곰팡이가 6.4$\times$105~107개, 효모는 1.4$\times$104~107개로 나타났고, 이 중에서 곰팡이 169균주, 효모 103균주를 분리하였으며 전분당화력이 좋은 곰팡이 16균주와 효모 1균주를 선발하였다. 이 중에서 전분당화 균주의 효소활성을 분석한 결과 Aspergillus속으로 동정된 A8-3이 glucoamylase 활성, 액화력, xylanase 활성이 가장 높았고, Rhizopus속으로 동정된 B23-3은 당화력이 가장 우수하였다. 우수효모를 선발하기 위하여 pH, 무게 감량, 내당성, 내알코올성 등을 측정한 결과, Saccharomyces속인 A10-4가 가장 우수하였다. 같은 원료비율로 만든 누룩에 우수균주를 접종하였을 때, 단일 균주를 처리할 때보다 A8-3과 B23-3인 두 균주를 혼합하여 처리한 경우가 당화력이 높게 나타났다. 누룩을 원반형의 누룩과 팰릿(개량형) 형태로 만들어 혼합종균 배양액을 접종한 후 당화력을 측정한 결과, 비슷한 당화력을 나타내었다. 개량형 누룩을 사용하여 양조하는 경우, 좁쌀주 양조에 발효효율을 높일 수 있을 것으로 판단되었다. 수집된 누룩은 수분이 10~13%, 총당은 55~70%, 조단백질은 10~18% 조지방은 0.2~l.0%, 회분은 1.8~2.1%이었다. 본 연구에서 제조한 누룩은 수분이 12~15%, 총당은 61~7l%, 조단백질은 15~20%, 조지방은 0.4~1.5%, 회분은 1.1~1.5%이었다.

• Korean Journal of Microbiology
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• v.33 no.4
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• pp.267-273
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• 1997

Various physico-chemical and microbiological parameters of a composting system were compared with respect to their potential use for the monitoring and evaluation of composting processes for cattle manure. The temperature changed within a range of $30-65^{\circ}C$ during the whole composting process, and the period of active composting (>$40^{\circ}C$) persisted for 16 days. The concentrations of total carbon, total nitrogen, and organic matter decreased by 15% during active composting, but significant changes in C/N ratio were not observed. The decrease of temperature in the latter period of active composting caused a decrease of $NH_4^+-N$ and an increase of $NO_3^--N$ in the composting pile. When temperature exceeded $50^{\circ}C$, the population of thermophiles was higher than that of mesophiles by more than 1 or 2 orders of magnitude. Correlation analyses showed that amylase activity correlated positively with the population of mesophiles and reducing sugar content, but negatively with the population of thermophiles. Amylase activity was higher at the beginning of active composting, whereas cellulase, xylanase and ligninase activities which showed close relationship with each other, increased continually during active cornposting, suggesting the distinction of temporal niches between amylose-degrading and lignocellulose-degrading bacteria in the same habitat.

• Journal of Korea Foresty Energy
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• v.23 no.2
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• pp.21-28
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• 2004

Three different strains of Lentinula edodes, Sanlim 5-Ho, Sanlim 6-Ho and Nongki 3-Ho, were cultured in the sawdust media of Mongolian oak(Quercu mongolica Fisch) for 90 days under dark and light conditions(each 30 days) and fruiting period(30 days). Weight loss of sawdust media was determined after fungal cultures and the contents of ergosterol in fungal mycelia were quantified by HPLC analysis followed by solvent extraction. Compared with the two other fungal strains$(8\%)$, weight loss of Sanlim 5-Ho was slightly lowered to $7\%$. The level of ergosterol content, a parameter for fungal growth, was continuously enhanced in Sanlim 5-Ho for dark and light incubation periods. However, Sanlim 6-Ho and Nongki 3-Ho recorded the maximized fungal growth under light condition. In fruiting periods the ergosterol contents were lowered in the three strains. Intra- and extracellular enzymes during cultural and fruiting periods were also characterized. The activity of Mn-peroxidase and laccase, which are characteristics enzymes for white rot fungi as lignin degrading enzymes, were determined as a high level overall the periods. As cellulose degrading indicators, the activity of CMCase, avicelase, xylanase and glucanase were detectable in initial incubation period.