• Korean Journal of Microbiology
• /
• v.42 no.4
• /
• pp.257-264
• /
• 2006

Fifty eight Cryptococcus neoformans strains isolated from clinical and environmental sources in Korea were examined for their serotypes and extracellular enzyme activities. Among the 51 strains isolated from clinical sources, 48 strains were serotype A (94.1%), 2 strains were serotype B (3.92%), and 1 strain was serotype D (1.96%). All seven environmental strains isolated from pigeon excreta were identified as serotype A. All isolates of C. neoformtans were positive for the production of extracellular proteinase and phospholipase. In the API-ZYM system, all fifty eight isolates produced alkaine phosphatase, esterase C4, esterase lipase: C8, leucine arylamidase, acid phosphatase, naphthol-AS-BI-phosphohydrase, $\alpha$-glucosidase and $\beta$-glucosidase. Thirty nine isolates (67.2%) of C. neoformans produced N-acetyl-$\beta$-glucosidase. Two isolates, serotype B, and B only one serotype A produced $\beta$-glucuronidase. Analysis of enzymatic profiles to 21 enzymes revealed four biotypic patterns among the 58 strains. The enzymatic patterns of C. neoformans isolated from clinical and environmental sources represented a significant relationship with the serotypes.

• Journal of Life Science
• /
• v.20 no.7
• /
• pp.999-1004
• /
• 2010

Investigations were carried out on a $\beta$-glucosidase produced by Aspergillus niger under solid-state fermentation conditions as a model of enzyme recovery from fermented wheat bran. The leaching efficiency of distilled water to recover the enzyme from the fermented bran was higher than acetate buffer, citrate buffer, citrate-phosphate buffer and 5% methanol; thus, the conditions were further optimized with distilled water as the extracting agent. After fermented bran was washed three times with distilled water for 1.5 hr each under shaking conditions at 1:5 solid to solvent ratio, a maximum recovery of 0.025 U/g of wheat bran was obtained.

• Journal of the Korean Wood Science and Technology
• /
• v.51 no.4
• /
• pp.270-282
• /
• 2023

Lower termites need symbiotic microbes for cellulose digestion. Elizabethkingia miricola strain BM10 has been proposed as a symbiotic microbe that assists in low-temperature digestion and metabolism of Reticulitermes speratus KMT1, a termite on Bukhan Mountain, Seoul, Korea. In E. miricola strain BM10, β-glucosidase genes expressed at 10℃ were identified, and the psychrophilic enzymatic characteristic was confirmed by heterogeneously expressed proteins. Crude β-glucosidase in the culture broth of E. miricola strain BM10 showed specific enzymatic properties, and its substrate affinity was 4.69 times higher than that of Cellic CTec2. Among the genes proposed as β-glucosidase, two genes, bglB_1 and bglA_2, whose gene expression was more than doubled at 10℃ than at 30℃, were identified. They were heterogeneously expressed in Escherichia coli and identified as psychrophilic enzymes with an optimal reaction temperature of about 20℃-25℃. In this study, E. miricola strain BM10, a symbiotic bacterium of lower termites, produced psychrophilic β-glucosidases that contribute to the spread of the low-temperature habitat of a lower termite, R. speratus KMT1.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.22 no.3
• /
• pp.569-574
• /
• 2008

The GUE6 was isolated from ethyl acetate fraction of Glycyrrhiza uralensis and confirmed as liquiritin. Liquiritin(LQ) treated with ${\beta}$-glucosidase from plant(Prunus dulcis) and bacteria(Lactobacillus pentosus) crude enzymes. The ${\beta}$-glucosidase activities of crude enzymes were 229.8 U/g(Prunus dulcis) and 19.17 U/ml(Lactobacillus pentosus), respectively. Liquiritin(LQ) biotransformed into liquiritigenin(LQG) by ${\beta}$-glucosidase from crude enzymes. The EtOAc fraction(GUE6) and the converted product were identified as liquiritin and liquiritigenin, by TLC chromatogram, $^{1}H$-NMR and $^{13}C$-NMR.

• Korean Journal of Microbiology
• /
• v.22 no.3
• /
• pp.167-173
• /
• 1984

The cellabiase (${\beta}$-glucosidase) gene in a Cellulomonas sp. CS1-1 was cloned into E. coli HB101 using the vector plasmid pBR322, and the expression of the gene in E. coli studied. The chromosomal DNA of the cellulomonas was digested by seveal restriction enzymes, each of which has only one cleaving site in plasmid pBR322. The recombinant plasmid, pSB2, created with Sal I frament, was expressed for the cellobiase gene in E. coli. The recombiant plasmid was estimated to contain 6.4 Kb foreign DNA at the Sal I site of plasmid pBR322 and the inserted DNA was mapped by single and double digestion with several enzymes. E. coli HB101(pSB2) has slowly grown in a mineral liquid medium containing cellobiose as a sole carbon source. The cellobiase activity in the transformed E. coli was 132 units per liter, which is equivalent to one twenty fifth of that in doner strain Cellulomonas sp. CS1-1. The transforned cell with plasmid containing cellulase gene grow well in the LB mediuns. The synthesis of cellobiase in the strain, E. coli HB101 (pSB2), was inhibited by glucose and at high concentration of cellobiose, and induced by cellobiose at low concentration.

• Journal of Microbiology and Biotechnology
• /
• v.25 no.2
• /
• pp.174-177
• /
• 2015

A potent α-glucosidase inhibitor (compound I) was isolated from coffee brews by activity-based fractionation and identified as a β-carboline alkaloid norharman (9H-pyrido[3.4-b]indole) on the basis of mass spectroscopy and nuclear magnetic resonance spectra (¹H NMR, ¹³C NMR, and COSY). The norharman showed potent inhibition against α-glucosidase enzyme in a concentration-dependent manner, with an IC₅₀ value of 0.27 mM for maltase and 0.41 mM for sucrase. A Lineweaver-Burk plot revealed that norharman inhibited α-glucosidase enzyme uncompetitively, with a K_i value of 0.13 mM.

• Journal of Microbiology and Biotechnology
• /
• v.24 no.8
• /
• pp.1073-1080
• /
• 2014

A total of 10 cellulase-producing bacteria were isolated from soil samples irrigated with paper and pulp mill effluents. The sequencing of 16S rRNA gene revealed that all isolates belonged to different species of genus Bacillus. Among the different isolates, B. subtilis IARI-SP-1 exhibited a high degree of ${\beta}$-1,4-endoglucanase (2.5 IU/ml), ${\beta}$-1,4-exoglucanase (0.8 IU/ml), and ${\beta}$-glucosidase (0.084 IU/ml) activity, followed by B. amyloliquefaciens IARI-SP-2. CMC was found to be the best carbon source for production of endo/exoglucanase and ${\beta}$-glucosidase. The ${\beta}$-1,4-endoglucanase gene was amplified from all isolates and their deduced amino acid sequences belonged to glycosyl hydrolase family 5. Among the domains of different isolates, the catalytic domains exhibited the highest homology of 93.7%, whereas the regions of signal, leader, linker, and carbohydrate-binding domain indicated low homology (73-74%). These variations in sequence homology are significant and could contribute to the structure and function of the enzyme.

• Korean Journal of Food Science and Technology
• /
• v.28 no.5
• /
• pp.981-986
• /
• 1996

We have conducted this study to examine effect of kimchi intake on the composition of human large intestinal bacteria. Two hundred grams of kimchi were administered to 10 healthy young volunteers (20-30 years old) every day for 2 weeks, followed by 2 weeks of non-intake period. The non-intake-intake cycle was repeated for 10 weeks. Except antibiotics and materials which contain live bacteria, subjects were allowed to eat ad libitum. The composition of intestinal microflora (Bacteroides, Bifidobacterium, Escherichia coli, Streptococcus, Lactobacillus, Leuconostoc, Staphylococcus, Clostridium perfringens) was examined a1 the last day of each period. $\beta-Glucosidase$ and $\beta-glucuronidase$ activities, pH and moisture content of the fecal samples were also measured. During the administration of kimchi, the cell counts of Lactobacillus and Leuconostoc increased significantly (p<0.05), whereas those of other bacteria did not change significantly. The enzyme level of $\beta-glucosidase$ and $\beta-glucuronidase$ decreased during kimchi intake (p<0.05). Results indicate that a portion of lactic acid bacteria present in kimchi can pass human stomach and reside in the large intestinal tract.

• The Korean Journal of Mycology
• /
• v.40 no.3
• /
• pp.152-158
• /
• 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
• /
• v.49 no.4
• /
• pp.369-376
• /
• 2013

We isolated the ${\beta}$-glucosidase producing bacteria (BGB) in ginseng root system (rhizosphere soil, rhizoplane, inside of root). Phylogenetic analysis of the 28 BGB based on the 16S rRNA gene sequences, BGB from rhizosphere soil belong to genus Stenotrophomonas (3 strains), Bacillus (1 strain), and Pseudoxanthomonas (1 strain). BGB isolates from rhizoplane were Stenotrophomonas (16 strains), Streptomyces (1 strain) and Microbacterium (1 strain). BGB from inside of root were categorized into Stenotrophomonas (3 strains) and Lysobacter (2 strains). Especially, Stenotrophomonas comprised the largest portion (approximately 90%) of total isolates and Stenotrophomonas was a dominant group of the ${\beta}$-glucosidase producing bacteria. We selected strain 4KR4, which had high ${\beta}$-glucosidase activity (108.17 unit), could transform ginsenoside Rb1 into Rd, Rg3, and Rh2 ginsenosides. In determining its relationship on the basis of 16S rRNA sequence, 4KR4 strain was most closely related to Stenotrophomonas rhizophila e-$p10^T$ (AJ293463) (99.62%). Therefore, on the basis of these polyphasic taxonomic evidence, the ginsenoside Rb1 converting bacteria 4KR4 was identified as Stenotrophomonas sp. 4KR4 (=KACC 17635).