• The Korean Journal of Mycology
• /
• v.11 no.1
• /
• pp.15-21
• /
• 1983

Exodextranase from Aspergillus ustus was purified by chromatography and characterized by various conditions. The optimal pH of the purified dextranase was 6.5 and this enzyme was maximally activated at $40^{\circ}C$. The enzyme was stable at the temperature below $50^{\circ}C$. The enzyme was markedly inactivated by $Hg^{2+},\;Cu^{2+},\;KCN\;and\;Co^{2+},\;but\;Ba^{2+},\;Fe^{2+},$ cysteine, EDTA, and ascorbic acid enhanced the activity of the enzyme. The main products from the hydrolysis of dextran incubated with the dextranase were glucose, isomaltotriose and oligosaccharide. When dextran was incubated with the mixture of pullulanase and ${\alpha}-amylase$, it was hydrolyzed into glucose, isomaltose and oligosaccharide. Polysaccharides in the decade teeth powder were hydrolyzed by the dextranase into glucose, isomaltotriose and oligosaccharides. In the hydrolysis of the teeth powder with the mixture of dextranase, pullulanase and ${\alpha}-amylase$, were proved to be similar to the dextran hydrolysates.

• Journal of Korean Society of Water and Wastewater
• /
• v.25 no.3
• /
• pp.367-373
• /
• 2011

Mechanism of rapid mixing effect on chemical phosphorus removal is evaluated in this study. Assuming that chemical phosphorus removal is unaffected by mixing time, only rapid mixing intensity is evaluated. In order to find out the mechanism, it is hypothesized that rapid mixing affects the Al hydrolysis speciation, and that formation of more monomeric species ($Al^a$) results in better removal of phosphorus. According to a ferron assay, more $Al^a$ formed at higher mixing intensity than at lower intensity. Subsequent experiments revealed that better phosphorus removal was obtained at higher intensity than at lower intensity, in terms of the molar ratio of $Al_{added}/P_{removed}$. The proposed hypothesis was proved in this study. Chemical phosphorus removal is affected by rapid mixing intensity due to its effect on the Al hydrolysis speciation.

• Korean Journal of Environmental Agriculture
• /
• v.17 no.1
• /
• pp.5-10
• /
• 1998

The microbial degradation, photosensitizer-mediated photolysis, and bioceramic- accelerated degradation of the herbicide imazapyr were investigated using four types of soil. 1. Seven strains of microorganisms isolated from the soil A and the active sludge collected from the waste water disposal plant in CheongJu did not give any distinct degradation products in pure culture. When imazapyr (10ppm) was incubated for 14days with each of the 6strains of the known bacteria, they did not produce any noticeable products, either, suggesting that imazapyr was degraded very little by microorganisms in aqueous media. Meanwhile, when 50ppm of imazapyr was incubated in soil A and B for 6months, a degradation product of m/z 279 was detected. It turned out to be 2-[(1-carbamoyl-1,2-dimethylpropyl)carbamoyl]nicotinic acid, which was formed by the hydrolytic cleavage of the imidazolinone ring and by tautomerism. When imazapyr was exposed to sunlight, degradation rates were 14.6% under the control and 66.0, 76.5, 26.7, and 90.0% in the presence of PS-1 (100ppm), PS-1 (200ppm), PS-2(100ppm), and PS-3(100ppm), respectively, and a degradation product of m/z 149 was tentatively identified in the treatment of PS-1. 2. When soil C and D treated with bioceramic were incubated for 7weeks, the $^{14}C$-activities of $^{14}CO_2$ evolved were 2.03 and 1.12% of the originally applied ones, respectively, whereas those in control soils without bioceramic were 1.88 and 0.82% showing no significant defferences.After 5 weeks, however,the differences in the amounts of $^{14}CO_2$ between the two treatments increased gradually, suggesting the bioceramic effect.

• Journal of Life Science
• /
• v.21 no.1
• /
• pp.68-73
• /
• 2011

$\beta$-1,3-glucanase from Pyrococcus furiosus was applied for the saccharification of laminarin, which is a major oligo-saccharide component of brown algae, and the reaction mixture produced from laminarin was utilized as a substrate for alcohol fermentation using yeast. To prepare the recombinant $\beta$-1,3-glucanase, a $\beta$-1,3-glucanase gene was overexpressed in Escherichia coli and purified. Laminarin was degraded to an oligo- and mono-saccharide, such as glucose, after reaction with the purified recombinant $\beta$-1,3-glucanase, and the products after enzymatic treatment were confirmed by TLC and HPLC analysis. Decomposed laminarin after enzyme reaction was only added to the medium as a C-source for yeast alcohol production reaction. 0.3% alcohol production was detected from the cultured broth by gas chromatography after 48 hr of incubation. Further evaluation for optimal conditions of saccharification and alcohol fermentation can be suggested, as well as the possibility of using this enzymatic method to produce ethanol using laminarin.

• Journal of Life Science
• /
• v.27 no.9
• /
• pp.1003-1010
• /
• 2017

An open reading frame coding for mannanase predicted from the partial genomic sequence of Paenibacillus woosongensis was cloned into Escherichia coli by polymerase chain reaction amplification, and completely sequenced. This mannanase gene, designated man26AT, consisted of 3,162 nucleotides encoding a polypeptide of 1,053 amino acid residues. Based on the deduced amino acid sequence, Man26AT was identified as a modular enzyme, which included a catalytic domain belonging to the glycosyl hydrolase family 26 and two carbohydrate-binding modules, CBM27 and CBM11. The amino acid sequence of Man26AT was homologous to that of several putative mannanases, with identity of 81% for P. ihumii and identity of less than 57% for other strains of Paenibacillus. A cell-free extract of recombinant E. coli carrying the man26AT gene showed maximal mannanase activity at $55^{\circ}C$ and pH 5.5. The enzyme retained above 80% of maximal activity after preincubation for 1 h at $50^{\circ}C$. Man26AT was comparably active on locust bean gum (LBG), galactomanan, and kojac glucomannan, whereas it did not exhibit activity on carboxymethylcellulose, xylan, or para-nitrophenyl-${\beta}$-mannopyranoside. The common end products liberated from mannooligosaccharides, including mannotriose, mannotetraose, mannopentaose, and mannohexaose, or LBG by Man26AT were mannose, mannobiose, and mannotriose. Mannooligosacchrides larger than mannotriose were found in enzymatic hydrolyzates of LBG and guar gum, respectively. However, Man26AT was unable to hydrolyze mannobiose. Man26AT was intracellularly degraded into at least three active proteins with different molecular masses by zymogram.

• Korean Journal of Microbiology
• /
• v.54 no.2
• /
• pp.126-135
• /
• 2018

The characteristics of enzyme and gene for mannanase B had been reported from Cellulosimicrobium sp. YB-43 producing some kind of mannanase. A gene coding for the enzyme, named mannanase C (ManC), was expected to be located downstream of the manB gene. The manC gene was cloned by polymerase chain reaction and sequenced completely. From this nucleotide sequence, ManC was identified to consist of 448 amino residues and contain a carbohydrate binding domain CBM2 besides a catalytic domain, which was homologous to mannanase belonging to the glycosyl hydrolase family 5. The catalytic domain of ManC showed the highest amino acid sequence similarity of 55% with the mannanases from Streptomyces sp. SirexAA-E (55.8%; 4FK9_A) and S. thermoluteus (57.6%; BAM62868). The His-tagged ManC (HtManC) lacking N-terminal signal peptide with hexahistidine at C-terminus was produced and purified from cell extract of recombinant Escherichia coli. The purified HtManC showed maximal activity at $65^{\circ}C$ and pH 7.5, with no significant change in its activity at pH range from 7.5 to 10. HtManC showed more active on konjac and locust bean gum (LBG) than guar gum and ivory nut mannan (ivory nut). Vmax and Km values of the HtManC for LBG were 68 U/mg and 0.45 mg/ml on the optimal condition, respectively. Mannobiose and mannotriose were observed on TLC as major products resulting from the HtManC hydrolysis of mannooligosacharides. In addition, mannobiose and mannose were commonly detected as the hydrolyzed products of LBG, konjac and ivory nut.

• Agrochemical news magazine
• /
• v.24 no.4 s.187
• /
• pp.16-19
• /
• 2003

• The Bimonthly Magazine for Agrochemicals and Plant Protection
• /
• v.8 no.6
• /
• pp.17-27
• /
• 1987

• Journal of Marine Bioscience and Biotechnology
• /
• v.2 no.3
• /
• pp.142-148
• /
• 2007

An agar-degrading marine bacterium, strain AS-3 was isolated from the seawater. The strain AS-3 was identified as Algibacter lectus AS-3 by 16S rDNA sequence. The optimum medium for agarase activity of the isolated strain was determined to be marine medium, marine broth 2216 containing 0.1% agar as carbon source. An extracellular agarase was purified 6.9-fold from the culture supernatant by ammonium sulfate precipitation, ion exchange chromatography and gel filtration methods. The optimum pH and temperature for this enzyme were 7.0 and $40-50^{\circ}C$, respectively. Antioxidative activity of the strain AS-3 was 62.4% in the supernatant cultured for 12 h.

• Applied Biological Chemistry
• /
• v.33 no.1
• /
• pp.79-86
• /
• 1990

Cyclodextrin hydrolase from Bacillus stearothermophilus KFCC 21203 was purified and the properties of the purified enzyme were investigated. The enzyme was purified 15 folds with 77 % recovery by ammonium sulfate fractionation, DEAE-cellulose chromatography, and Ultro AcA 34 gel filtration. The specific activity and the molecular weight of the enzyme were 1.30 units/mg protein and about 29,500, respectively, The maximum activity of the enzyme was shown at $55^{\circ}C$ and pH 5.5. However, stable temperature and pH were $40^{\circ}C$ and $5.0{\sim}8.0$, respectively. The Km value for ${\gamma}-cyclodextrin$ was $3.78{\times}10^{-3}$ M. The degradation activity of the enzyme was selectively high for ${\gamma}-cyclodextrin$, and very low for ${\beta}-cyclodextrin$, but not for ${\alpha}-cyclodextrin$. The decomposed products of ${\gamma}-cyclodextrin$ were mainly glucose and maltose, and a little mlatotriose. The activity of the enzyme was very high for amylose, potato starch, corn starch, amylopectin and maltooligomer, and relatively high for glycogen and dextrin. The decomposed products of them were mainly glucose and maltose.