• Korean Journal of Food Science and Technology
• /
• v.16 no.4
• /
• pp.398-402
• /
• 1984

These experiments were conducted to investigate the substrate specificity, the hydrolysis products on the various carbohydrates and the hydrolysis rate on the various raw starches of the two purified glucoamylase produced by Rhizopus oryzae. Both of the glucoamylases hydrolyzed amylose, amylopectin, glycogen, soluble starch, pullulan, maltose, maltotriose, maltotetraose, maltopentaose, maltohexaose, maltoheptaose and maltooctaose, but did not act on ${\alpha}-cyclodextrin$, ${\beta}-cyclodextrin$, raffinose, sucrose and lactose. When the reaction mixture of glucoamylase and polysaccharides were incubated $37^{\circ}C$for 32 hours, glucoamylase I hydrolyzed amylopectin, soluble starch and amyloses completely, but hydrolyzing glycogen up to only about 88%. Glucoamylase II hydrolyzed the previous four polysaccharides up to about 100%. Both of the glucoamylases produced only glucose for various substrates and did not have any ${\alpha}-glucosyl$ transferase activity. Both of the glucoamylases hydrolyzed raw glutinous rice starch almost complety, wheras they acted on raw potato starch, raw green banana starch, raw arrow root starch, raw corn starch, raw yam starch and raw high amylose corn starch weakly. Glucoamylase II hydrolyzed raw starches at the higher rate than glucoamylase I.

• The Korean Journal of Mycology
• /
• v.18 no.4
• /
• pp.209-217
• /
• 1990

The influence of cellulosic and hemicellulosic substrates on the production of cellulase and xylanase complexes in Aspergillus niger was investigated. The culture conditions with different substrates exhibited profound effects on the level of endoglucanase (CMCase), ${\beta}-glucosidase$, endoxylanase and ${\beta}-xylosidase$, and on their isozyme patterns. However, intracellular and extracellular isozyme patterns of cellulase and xylanase complexes were qualitatively identical and appeared to be simultaneous in the early growth phase. Prolonged incubation led to the increase in the concentrations of isozymes with a little changes in the relative proportions of those isozymes. These results suggest that the biosynthesis of cellulase and xylanase complexes in A. niger is coordinately regulated at the level of induction. Moreover, multiple forms of extracellular cellulase and xylanase complexes seem to be the outcome of specific gene expression and should not be considered solely as the consequence of post-secretional modification of synthesized enzymes.

• Korean Journal of Microbiology
• /
• v.46 no.2
• /
• pp.183-191
• /
• 2010

In this study, we isolated 179 bacterial strains using benzene, phenol, ethylbenzene, aniline, cumene, toluene as growth substrate from TCE contaminated soils and wastewaters. All the 179 strains were screened for TCE (30 mg/L) removal (growth substrate 0.2 g/L, $30^{\circ}C$, pH 7, cell biomass 1.0 g/L (w/v)) under aerobic condition for 21 days. EK2 strain using aniline showed the highest removal efficiency (74.4%) for TCE degradation. This strain was identified as Delftia acidovorans as the results of API kit, 16S rDNA sequence and fatty acid assay. In the batch culture, D. acidovorans EK2 showed the bio-degradation for TCE in the various TCE concentration (10 mg/L to 200 mg/L). However, D. acidovorans EK2 did not show the bio-degradation in the TCE 250 mg/L. D. acidovorans EK2 also show the removal efficiency (99.9%) for 12 days in the low concentration (1.0 mg/L). Optimal conditions to degrade TCE 200 mg/L were cell biomass 1.0 g/L (w/v), aniline 0.5 g/L, pH 7 and $30^{\circ}C$. Removal efficiency and removal rate by D. acidovorans EK2 strain was 71.0% and 94.7 nmol/h for 21 days under optimal conditions. Conclusion, we expect that D. acidovorans EK2 may contribute on the biological treatment in the contaminated soil or industrio us wastewater.

• Journal of Korea Soil Environment Society
• /
• v.5 no.1
• /
• pp.97-108
• /
• 2000

A Gram-type negative bacteria that can utilize crude oil as the sole source of carbon and energy was isolated from an activated sludge of a local sewage treatment plant and identified tentatively as belonging to the genus Acinetobacter. The isolate could degrade n-alkanes and unidentified hydrocarbons in crude oil and utilize n-alkanes, hydrophobic substrates, as sole carbon and energy sources. n-Alkanes from tridecane (Cl3) to triacontane (C30) in crude oil were degraded simultaneously with no difference in degradation characteristics between the two close odd and even numbered alkanes in carbon numbers. The linear growth of the isolate and the degradation characteristics of Pr-alkanes suggested that the transport of substrates from the oil phase to the site where the substrates undergo the initial oxidation in microorganism might be the rate limiting in the biodegradation process of crude oil constituents. The remainder fraction of substrates after cultivation was considered to reflect the hydrocarbon inclusions in the cell mass, characteristics in Acinetobacter species, and to control the transport of substrates from crude oil phase. On the basis of the results, the isolate was considered to play an important role in the degradation study of hydrophobic environmental pollutants.

• The Microorganisms and Industry
• /
• v.27 no.1
• /
• pp.2-17
• /
• 2001

Cyclomaltodextrinase(CDase, EC 3.2.1.54), maltogenic amylase(EC 3.2.1.133). neopullulanase(EC 3.2.1.135)는 cyclomaltodextrin(CD), pullulan 및 전분을 가수분해하는 효소들이다. 이 효소들은 $\alpha$-1,4-Ο-glycosidic 결합에 작용하여 CD와 전분을 말토오스로 pullulan을 panose로 가수분해할 뿐만 아니라 올리고당들을 다양한 당 수용체 분자들의 C-3, C-4. C-6 수산기로 전이시키는 활성도 갖고 있다. 이러한 특성들은 기존의 $\alpha$-amylase를 비롯한 판수화물 분해효소들과 뚜렷이 구별되는 것으로 전분 분해효소들의 분류체계에 새로운 기준점을 제시한다고 하겠다. 본 총설에서는 CDase, maltogenic amylase, neopullulanase처럼 pullulan이나 전분보다 CD를 훨씬 더 잘 분해하는 효소들과 Thermoactinomyces vulgaris amylase II(TVA II)처럼 CD를 분해하기는 하나 pullulan을 더 잘 분해하는 효소들의 생화학적, 효소적, 구조적 특성들을 종합하여 소개하고자 하였다. 이 효소들은 40~60% 정도로 아미노산 서열이 동일하고, 세포 내에 존재하며, 분자량이 62~90 kDa로 $\alpha$-amylase보다 다소 크다. 아미노산 서열 비교분석 및 maltogenic amylase와 TVA II 등의 3차구조 분석 결과, 이 효소들은 아미노 말단에 보통 $\alpha$-amylase에는 존재하지 않는 약 130개 아미노산으로된 영역을 갖고 있어 이를 매개로 이합체를 형성할 수 있는 것으로 나타났다. 이합체-단위체 평형은 염 농도, 효소 농도, 산도 등에 의해 조절되고 단위체와 이합체 모두 효소환성을 갖고 있으나, 기질 특이성이 다르며 단위체는 전분을, 이합체는 CD를 선호하는데 이는 이합체 형성 시 활성부위의 구조적 변화에 따른 것으로 분석되었다. 본 총설에서는 CD 분해효소들의 다양한 기질 특이성을 올리고머 형성 등의 구조적 특성과 관련하여 논함으로써 관련 효소들의 분류체계를 보다 명확히 할 수 있는 자료를 제공하고자 하였으며, 이러한 효소들의 생리적 기능 및 산업적 이용에 대해 제안하고자 하였다.

• Korean Journal of Food Science and Technology
• /
• v.29 no.6
• /
• pp.1191-1195
• /
• 1997

This study was conducted to investigate the proteolytic properties of saewoojeot (salted and fermented shrimp) on various meat proteins. NaCl content was decreased less than 2% by electrodialysis. As electrodialysis time was passed, the protease activity was increased. The proteolytic activity of crude protease on muscle proteins of beef, pork, chicken was analyzed by SDS-PAGE. Crude enzyme easily degradated both heat-denatured and native meat proteins. Protein degradation was rapidly occurred within 5 min and most all myofibrilar protein was disappeared. Heat-denatured chicken meat (100%) was most easily degraded than heat-denatured pork meat (47%) and beef meat (31%).

• KSBB Journal
• /
• v.20 no.4
• /
• pp.317-322
• /
• 2005

Various recovery methods were investigated to maximize hemicellulose recovery from lignocellulosic material hydrolyzed by pure water. The pretreatment conditions of water hydrolysis were $170\~180^{\circ}C$ and 1 hour of reaction time. The percentage of hemicellulose solubilized increased as the temperature increased from 170 to $180^{\circ}C$. However, significant decomposition of sugar was observed at temperature of $180^{\circ}C$. From the results of water hydrolysis, the total amount of glucan in solid residue and liquid hydrolyzate was close to the total glucan in the original biomass. For hemicellulose, however, there was a significant difference between both contents. To prove this difference, various recovery methods were proposed. From the total sugar accountability (sugar in liquid + sugar in solid), it was confirmed that hemicellulose recovery in the hydrolyzate was increased if the product including both hydrolyzate and solid residue was physically stimulated by such as heating and ultrasound irradiation. This indicated that, in commercial scale processes that much bigger substrate sizes are used and a sufficient amount of leaching solvent can not be used after pretreatment, a significant amount of oligomers could be trapped in the solid matrix.

• Microbiology and Biotechnology Letters
• /
• v.16 no.2
• /
• pp.79-84
• /
• 1988

Dye materials and cross linking agents were used for the determination of $\beta$-glucanase activities. The objective of this study was to prepare the blue coloured substrates which are sensitive, specific and simple for the determination of $\beta$-glucanase in malt and Bacillus subtilis K-4-3 enzymes. This method is based on the principle of measuring colorimetrically the split product of coloured and cross linked substrate. The best coupling of dye stuff of $\beta$-glucan was cibacron blue 3G-A and the colour released can suitably be measured at 623nm. Optimal concentration of dye and cross linking agents was 1.5g and 1.25$m\ell$ under 0.1N NaOH. The sensitivity comparison proved that the stained $\beta$-glucan method is much more sensitive than the DNS method to determine reducing sugar released by the enzyme.

• The Korean Journal of Mycology
• /
• v.14 no.1
• /
• pp.25-30
• /
• 1986

The purposes of this study were to investigate enzyme components and its physiological activities of Sarcodon aspratus (Berk.) S. Ito which grows wildly in Korea, belonging to the family Thelephoraceae. The carpophores of the fungus was extracted with cooling distilled water and salted out by ammonium sulfate. The precipitate was purified by dialysing through visking tube against distilled water and then dissolved with pH 7.8 ammonia aqua, and the extract was filterated. The fraction of filtrate was obtained as light brown powder after lyophilization and determined proteolytic activity. Protease activity of Sarcodon aspratus (Berk.) S. Ito was about two-third of that of pepsin on casein by cup method. The proteolytic potency of this enzyme was found to be 500 unit/mg. This proved the efficacy of the mushroom when it was used as a folk medicine for treating indigestion of beef.

• Membrane Journal
• /
• v.10 no.2
• /
• pp.83-91
• /
• 2000

In order to improve functional properties, enzymatic hydrolysis of FPC (fish protein concentration) was achieved in ultrafiltration membrane reactor (MWCO 5,000). First, insoluble FPC was hydrolyzed by pepsin in batch reactor to decrease the fouling in ultrafiltration membrane reactor, and second hydrolysis was achieved by pronase E in ultrafiltration membrane reactor The optimum operating conditions in batch reactor using pepsin were at temperature 45$^{\circ}C$, pH 2.0 and the ratio of substrate to pepsin, 150 (w/w) After operating for 5hrs under optimum conditions, 89％ of total amount of initial FPC was hydrolyzed. The rate constants, $K_{m}$ and V$_{max}$, were 1.25％ and 0.89 mg/$m\ell$/min, respectively, and substrate inhibition was occured above 1.5％. The ultrafiltration membrane reactor was operated with recycling rate of 474 $m\ell$/min and transmembrane pressure of 15 psi. The permeate flux was increased by temperature, transmembrane pressure, but the permeate flux was fixed by pH. The optimum ratio of substrate to pronase E was 200(w/w) and the productivity of ultrafiltration membarane reactor was 702 mg/mg -enzyme, that of batch reactor was 51mg/mg-enzyme. Molecular weight distributions tot first and second hydrolysates were from 2,500 Da to 20,000 Da and from 700 Da to 10,000 Da, respectivelyly.