• The Korean Journal of Ecology
• /
• 제18권3호
• /
• pp.409-418
• /
• 1995

As a part of studying the function and structure of the mudflat environment of the Yellow Sea, seawater samples in the overlying waters of sediment near Daesan were collected every hour on March 29 (spring tides) and on April 5 (neap tides), 1995 to study the diurnal distribution of aerobic saprophytic bacteria and their extracellular enzyme activities. The diurnal distribution of aerobic saprophytic bacteria ranged from 1.0 X $10^{2}$ to 7.07 X $10^{3}$ cfu /ml at spring tides and from 1.0 X $10^{2}$ to 8.3 X $10^{3}$ cfu /ml at neap tides. The diurnal variations of aerobic saprophytes at the suface waters were greater than those of middle and bottom waters. However, th diurnal fluctuation of saprophyte numbers at spring tides showed no significant difference compared with that at neap tides. The numbers of three physiological groups of aerobic hacteria (proteolytic, lipolytic and amylolytic bacteria) at the surface waters during spring and neap tides were lower than those at the middles and bottom waters. The diurnal variations of five extracellular enzyme activities at the surface waters during the survey period showed lower values than those at the middle and botton waters. Among the measured extracellular enzyme activities, phosphatase showed the highest. However, the activities of amylase, chitinase and cellulase showed a similar tendency.

• Journal of Microbiology and Biotechnology
• /
• 제20권9호
• /
• pp.1307-1313
• /
• 2010

An extracellular ${\alpha}$-amylase from Lactococcus lactis IBB500 was purified and characterized. The optimum conditions for the enzyme activity were a pH of 4.5, temperature of $35^{\circ}C$, and enzyme molecular mass of 121 kDa. The genome analysis and a plasmid curing experiment indicated that $amy^+$ genes were located in a plasmid of 30 kb. An analysis of the phylogenetic relationships strongly supported a hypothesis of horizontal gene transfer. A strong homology was found for the peptides with the sequence of ${\alpha}$-amylases from Ralstonia pikettii and Ralstonia solanacearum. The protein with ${\alpha}$-amylase activity purified in this study is the first one described for the Lactococcus lactis species, and this paper is the first report on a Lactococcus lactis strain belonging to the amylolytic lactic acid bacteria (ALAB).

• 한국균학회지
• /
• 제30권2호
• /
• pp.147-151
• /
• 2002

Trichoderma속 균주는 느타리버섯 재배 시 발생되는 버섯 푸른곰팡이병의 주요 원인균이다. 후발효된 버섯 배지로부터 버섯 푸른곰팡이병균에 항균활성을 나타내는 길항세균(KATB 99121, KATB 99122 및 KATB 99123)을 분리하였다. 분리세균 중 KATB 99121은 T. harzianum(4균주). T. viride 및 T. hamatum과 동물병원성 곰팡이 Candida albicans에 대하여 우수한 억제 활성이 관찰되었고, 특히 세균의 배양상등액 접종실험에서 강한 항균활성을 보였다. 또한, KATB 99121은 전분, 단백질 및 섬유소를 분해하는 효소를 세포외로 분비하는 것으로 관찰되었고, KATB 99122와 KATB 99123은 전분, 단백질, 섬유소 분해효소는 물론 지질 분해효소도 분비하고 있었으며 ${\beta}$-glucosidase활성도 높은 것으로 확인되었다. 앞으로 이들 길항세균들을 이용하여 느타리버섯 푸른곰팡이병 방제를 위한 미생물 살균제의 개발에 대한 연구를 수행할 예정이다.

• 한국미생물·생명공학회지
• /
• 제25권2호
• /
• pp.189-196
• /
• 1997

A producer of inhibitor against ${\beta}-glucosidase$ of Penicillium sp.-L4 was screened from Actinomycetes, and the isolated strain was identified as Streptomyces sp. The inhibitor produced was very stable against heat, acidic and alkaline conditions, proteolytic and amylolytic enzymes. The inhibotor was purified from culture broth through activated carbon treatment, ultrafiltration, anion and cation exchange, activated carbon columm, acetone precipitation and preparative HPLC. It showed inhibitory activities against a variety of dissacharide hydrolyzing enzymes produced by P.sp.-L4, and the mode of inhibition was competitive. Its structure and molecular formular was elucidated by IR, $^1H\;and\;^{13}C$ NMR and FAB/Mass spectrometry, which was identified as 1-deoxynojirimycin (dNM). dNM showed inhibitory effects on the cell growth and hydrolytic enzyme action of P.sp.-L4 on agar plate and infected lemon peel.

• Biotechnology and Bioprocess Engineering:BBE
• /
• 제10권1호
• /
• pp.52-59
• /
• 2005

The study was targeted to saccharify foodwastes with the cellulolytic and amylolytic enzymes obtained from culture supernatant of Trichoderma harzianum FJ1 and analyze the kinetics of the saccharification in order to enlarge the utilization in industrial application. T. harzianum FJ1 highly produced various cellulolytic (filter paperase 0.9, carboxymethyl cellulase 22.0, ${\beta}$-glucosidase 1.2, Avicelase 0.4, xylanase 30.8, as U/mL-supernatant) and amylolytic (${alpha}$-amylase 5.6, ${\beta}$-amylase 3.1, glucoamylase 2.6, as U/mL-supernatant) enzymes. The $23{\sim}98\;g/L$ of reducing sugars were obtained under various experimental conditions by changing FPase to between $0.2{\sim}0.6\;U/mL$ and foodwastes between $5{\sim}20\%$ (w/v), with fixed conditions at $50^{\circ}C$, pH 5.0, and 100 rpm for 24 h. As the enzymatic hydrolysis of foodwastes were performed in a heterogeneous solid-liquid reaction system, it was significantly influenced by enzyme and substrate concentrations used, where the pH and temperature were fixed at their experimental optima of 5.0 and $50^{\circ}C$, respectively. An empirical model was employed to simplify the kinetics of the saccharification reaction. The reducing sugars concentration (X, g/L) in the saccharification reaction was expressed by a power curve ($X=K{\cdot}t^n$) for the reaction time (t), where the coefficient, K and n. were related to functions of the enzymes concentrations (E) and foodwastes concentrations (S), as follow: $K=10.894{\cdot}Ln(E{\cdot}S^2)-56.768,\;n=0.0608{\cdot}(E/S)^{-0.2130}$. The kinetic developed to analyze the effective saccharification of foodwastes composed of complex organic compounds could adequately explain the cases under various saccharification conditions. The kinetics results would be available for reducing sugars production processes, with the reducing sugars obtained at a lower cost can be used as carbon and energy sources in various fermentation industries.

• 한국응용과학기술학회지
• /
• 제26권1호
• /
• pp.10-17
• /
• 2009

This study investigated the effect of kilning condfition on the diastatic power and activities of protease, $\alpha$-amylase, and $\beta$-amylase in rice malt. Common rice (Oryza sativa) was steeped at $30^{\circ}C$ for 50 h, germinated at $30^{\circ}C$ for 7 days, and kilned at $50^{\circ}C$ for 24 h. The moisture content and enzymatic activities were determined under various kilning times. As a result, the moisture content was reduced from 42.1 % to 3.9% after 24 h of kilning at $50^{\circ}C$. The protease activity of rice malt showed lower value than that of barley malt. All enzymatic activities were decreased during the kilning stage. Results indicated that after prolonged kilning at $50^{\circ}C$, the inactivation of hydrolytic enzymes might be occurred. Even though the amylolytic activity of malted rice showed low value, the rice malt shows the potential characteristics as ingredient for the brewing and cereal industries.

• 미생물학회지
• /
• 제27권3호
• /
• pp.216-220
• /
• 1989

Aamylase 활성이 높은 Aspergillus oryzae와 알콜발효능이 있는 Saecharomyccs cerevisiae의 원형질체융합을 위한 기초연구로서, amylase 활성이 있는 A. oryzae의 종내원형질체를 융합시켜 이들융합체의 특성을 조사하였다. 영양요구성 돌연변이 균주의 mycellia로부터 원형질체를 생성하기 위해서는 lytic enzyme으로 Novozyme 234가 효과적이였고 완충용액의 pH는 5.5에서 6.0사이가 최적이었다. F usogen으로 30% PEG4,000를 사용하였을 때 효과적으로 원형질체의 융합이 이루어졌으며 이들 융합체의 대부부은 heterokaryons이었다. 원형질체의 형태와 PEG처리후 융합되는 과정을 광학현미경으로 관찰하였다. 원형질체의 재생율은 재생배지와 균주에 따라 1.46~14%이었고, A. oryzae 종내융합율은 0.12-0.16이었다. 융합체의 DNA함량을 조사한 결과 모균주보다 약 1.5배정도 증가됨을 보였고 융합체들의 amylase 활성은 융합체에 따라 다소 차이를 냐타내었다. 가장 높은 amylase 활성을 나타낸 융합체들의 amylase 활성은 융합체에 따라 다소 차이를 나타내었다. 가장 높은 amylase 활성을 나타낸 융합체 F2-2에 있어서는 야생균주 ATCC 22788의 그것보다 amylase 활성이 약 1.5배 가량 높았다.

• 미생물학회지
• /
• 제44권3호
• /
• pp.264-269
• /
• 2008

$\beta$-Amylase를 생산하여 전분 분해능을 갖는 산업용 효모를 개발하기 위해 산업용 Saccharomyces cerevisiae에서 Achlya bisexualis $\beta$-amylase (BAMY)유전자를 ADC1 promoter에 연결하여 구성적으로 발현시켰다. 효모의 형질전환은 $\delta$-서열을 재조합 부위로 하는integration 시스템을 이용하였다. Integration 시스템의 세균 유전자 부분은 제거되고 BAMY 유전자와 $\delta$-서열을 갖고 있는 짧은integrative cassette를 제조하였다. BAMY 유전자를 발현하는 재조합 S. cerevisiae 형질전환체는 세포외 배지로 45 kDa의 $\beta$-amylase를 분비하였고, $\beta$-amylase 활성은 A. bisexualis에 비해 약 18.5배 높았다. 형질전환체에 다중도입된 BAMY 유전자는 비선택배지에서 100세대 생장 후에도 안정되게 유지되었다. 각종전분을 기질로 했을 매 $\beta$-amylase의 활성은soluble starch를 기질로 했을 경우와 유사하게 높았고, 가수분해산물 분석 결과 maltose가 주 분해산물이었다.

• 생명과학회지
• /
• 제17권9호통권89호
• /
• pp.1182-1190
• /
• 2007

연부균인 Pectobacterium carotovorum subsp. carotovorum LY34로부터 이소아밀라제 유전자 (glgX)를 클로닝한 후 대장균 숙주에서 발현시켰다. 이 효소는 ${\alpha}-1$,6-글루코시드 결합을 가수분해하였으나 ${\alpha}-1$,4-글루코시드 결합은 가수분해 하지 못하였다. 유전자는 658개의 아미노산을 암호화하는 1,977개의 DNA 염기서열로 이루어져 있었고 이 유전자에 의해 암호화되는 아미노산 서열을 다른 아밀라제 효소들과 비교한 결과 이소아밀라제 유전자와 유사하였으며 4개의 보존 지역을 확인하였다. SDS-PAGE에 의해 확인된 단백질의 크기는 약 74 kDa 이었다. 효소 활성은 pH 7.0, $40^{\circ}C$에서 가장 높은 활성을 나타났으며 $Ca^{2+}$ 첨가로 활성이 증가되었다. 이 효소의 보존되어 있는 아미노산 중에 글루탐산 370번, 아스파르트산 335번 및 442번 잔기를 알라닌으로 치환시킨 결과 활성이 약해졌다. 이 결과로부터 이들 잔기들이 효소활성에 중요한 역할을 하는 것으로 추정된다.

• Asian-Australasian Journal of Animal Sciences
• /
• 제30권2호
• /
• pp.171-180
• /
• 2017

Objective: This study investigated the association of enzyme-producing microbes and their enzymes with starch and hemicellulose degradation during fermentation of total mixed ration (TMR) silage. Methods: The TMRs were prepared with soybean curd residue, alfalfa hay (ATMR) or Leymus chinensis hay (LTMR), corn meal, soybean meal, vitamin-mineral supplements, and salt at a ratio of 25:40:30:4:0.5:0.5 on a dry matter basis. Laboratory-scale bag silos were randomly opened after 1, 3, 7, 14, 28, and 56 days of ensiling and subjected to analyses of fermentation quality, carbohydrates loss, microbial amylase and hemicellulase activities, succession of dominant amylolytic or hemicellulolytic microbes, and their microbial and enzymatic properties. Results: Both ATMR and LTMR silages were well preserved, with low pH and high lactic acid concentrations. In addition to the substantial loss of water soluble carbohydrates, loss of starch and hemicellulose was also observed in both TMR silages with prolonged ensiling. The microbial amylase activity remained detectable throughout the ensiling in both TMR silages, whereas the microbial hemicellulase activity progressively decreased until it was inactive at day 14 post-ensiling in both TMR silages. During the early stage of fermentation, the main amylase-producing microbes were Bacillus amyloliquefaciens (B. amyloliquefaciens), B. cereus, B. licheniformis, and B. subtilis in ATMR silage and B. flexus, B. licheniformis, and Paenibacillus xylanexedens (P. xylanexedens) in LTMR silage, whereas Enterococcus faecium was closely associated with starch hydrolysis at the later stage of fermentation in both TMR silages. B. amyloliquefaciens, B. licheniformis, and B. subtilis and B. licheniformis, B. pumilus, and P. xylanexedens were the main source of microbial hemicellulase during the early stage of fermentation in ATMR and LTMR silages, respectively. Conclusion: The microbial amylase contributes to starch hydrolysis during the ensiling process in both TMR silages, whereas the microbial hemicellulase participates in the hemicellulose degradation only at the early stage of ensiling.