• 제목/요약/키워드: enzymatic degradation

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Conversion Characteristics of Chemical Constituents in Liriodendron tulipifera and Their Influences on Biomass Recalcitrance during Acid-Catalyzed Organosolv Pretreatment

  • Ki-Seob GWAK;JunHo SHIN;Chae-Hwi YOON;In-Gyu CHOI
    • Journal of the Korean Wood Science and Technology
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    • 제52권2호
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    • pp.101-117
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    • 2024
  • The conversion characteristics of the major components of Liriodendron tulipifera were investigated during acid-catalyzed organosolv pretreatment. Glucan in L. tulipifera was slowly hydrolyzed, whereas xylan was rapidly hydrolyzed. Simultaneous hydrolysis and degradation of xylan and lignin occurred; however, after complete hydrolysis of xylan at higher temperatures, lignin remained and was not completely degraded or solubilized. These conversion characteristics influence the structural properties of glucan in L. tulipifera. Critical hydrolysis of the crystalline regions in glucan occurred along with rapid hydrolysis of the amorphous regions in xylan and lignin. Breakdown of internal lignin and xylan bonds, along with solubilization of lignin, causes destruction of the lignin-carbohydrate complex. Over a temperature of 160℃, the lignin that remained was coalesced, migrated, and re-deposited on the surface of pretreated solid residue, resulting in a drastic increase in the number and content of lignin droplets. From the results, the characteristic conversions of each constituent and the changes in the structural properties in L. tulipifera effectively improved enzymatic hydrolysis in the range of 140℃-150℃. Therefore, it can be concluded that significant changes in the biomass recalcitrance of L. tulipifera occurred during organosolv pretreatment.

Biological Pretreatment of Softwood Pinus densiflora by Three White Rot Fungi

  • Lee, Jae-Won;Gwak, Ki-Seob;Park, Jun-Yeong;Park, Mi-Jin;Choi, Don-Ha;Kwon, Mi;Choi, In-Gyu
    • Journal of Microbiology
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    • 제45권6호
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    • pp.485-491
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    • 2007
  • The effects of biological pretreatment on the Japanese red pine Pinus densiflora, was evaluated after exposure to three white rot fungi Ceriporia lacerata, Stereum hirsutum, and Polyporus brumalis. Change in chemical composition, structural modification, and their susceptibility to enzymatic saccharification in the degraded wood were analyzed. Of the three white rot fungi tested, S. hirsutum selectively degraded the lignin of this sortwood rather than the holocellulose component. After eight weeks of pretreatment with S. hirsutum, total weight loss was 10.7%, while lignin loss was the highest at 14.52% among the tested samples. However, holocellulose loss was lower at 7.81 % compared to those of C. lacerata and P. brumalis. Extracelluar enzymes from S. hirsutum showed higher activity of ligninase and lower activity of cellulase than those from other white rot fungi. Thus, total weight loss and changes in chemical composition of the Japanese red pine was well correlated with the enzyme activities related with lignin- and cellulose degradation in these fungi. Based on the data obtained from analysis of physical characterization of degraded wood by X-ray Diffractometry (XRD) and pore size distribution, S. hirsutum was considered as an effective potential fungus for biological pretreatment. In particular, the increase of available pore size of over 120 nm in pretreated wood powder with S. hirsutum made enzymes accessible for further enzymatic saccharification. When Japanese red pine chips treated with S. hirsutum were enzymatically saccharified using commercial enzymes (Cellulclast 1.5 L and Novozyme 188), sugar yield was greatly increased (21.01 %) compared to non-pre treated control samples, indicating that white rot fungus S. hirsutum provides an effective process in increasing sugar yield from woody biomass.

메밀껍질의 효소분해에 의한 수용성 식품섬유소의 생산 및 기능적 특성 (Production of Soluble Dietary Fiber of Buckwheat Hulls by Enzymatic Depolymerzation and its Characteristics)

  • 임희진;박보연;윤경영
    • 한국식품과학회지
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    • 제48권2호
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    • pp.97-103
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    • 2016
  • 본 연구는 메밀 알곡에 비해 유효성분이 많음에도 불구하고 식품학적 가치가 떨어져 폐기되고 있는 메밀껍질을 기능성 식품소재로 활용하기 위해 메밀껍질을 효소로 분해하여 수용성 식품섬유를 생산하고자 하였다. 메밀껍질을 효소를 이용하여 72시간 분해하여 수용성 식품섬유의 수율을 측정한 결과, 72시간 효소분해 후 셀룰로스 및 헤미셀룰로스 분획으로부터 얻은 수용성 식품섬유는 각각 60.5 g/kg, 123.7 g/kg이었으며, 총 수용성 식품섬유의 수율은 129.8 g/kg이었다. 겔 크로마토그래피에 의한 수용성 식품섬유의 분자량 추이를 측정한 결과, 분해 시간이 증가함에 따라 저분자의 피크가 크게 증가하여 효소 반응 시간이 증가할수록 분해가 진행되었다. 효소분해되지 않은 메밀껍질의 수용성 식품섬유에 비해 효소분해에 의해 생산된 식품섬유소의 산화방지 활성이 높게 나타났으며, 대조군에 비해 높은 포도당 및 담즙산 흡수 지연효과를 보였다. 따라서 메밀껍질로부터 생산된 수용성 식품섬유소는 산화방지를 비롯한 포도당 및 콜레스테롤의 흡수저하 효과를 가진 건강기능식품 소재로 사용될 수 있을 것으로 기대된다.

효소적 분해에 의한 배추부산물 hemicellulose 분획으로부터 수용성 식이섬유소 함유 가수분해물의 생산 (Production of Enzymatic Hydrolysate Including Water-soluble Fiber from Hemicellulose Fraction of Chinese Cabbage Waste)

  • 박서연;윤경영
    • 한국식품과학회지
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    • 제47권1호
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    • pp.6-12
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    • 2015
  • 본 연구에서는 농산부산물인 배추 겉잎의 이용성을 증진시키기 위하여 배추의 불용성 식이섬유인 hemicellulose를 분획한 후 효소 처리하여 수용성 식이섬유를 함유한 가수분해물을 생산하고자 하였다. 이를 위해 다양한 pH, 온도, 기질농도 및 효소농도에서 hemicellulose 분획을 효소 처리한 후 환원당 함량을 측정한 결과, pH 5.0, $40^{\circ}C$, 효소농도 45 unit (Shearzyme plus), 21 unit Viscozyme L)의 조건으로 가수분해 했을 때 가장 높은 분해율을 나타내었다. 선정된 조건으로 72시간 가수분해하여 수율을 측정한 결과, Shearzyme plus 및 Viscozyme L 처리 시 각각 22.64%와 24.73%의 수율을 보였다. 또한 알코올 불용성 식이섬유의 겔크로마토그래피에 의한 분자량 분포를 확인한 결과, Shearzyme plus 및 Viscozyme L에 의해 생성된 식이섬유는 반응 시간이 증가함에 따라 저분자화 되는 것을 확인 할 수 있었다. 이상의 결과에서 배추 부산물 hemicellulose 분획을 효소로 가수분해함으로써 불용성 식이섬유가 저분자화 되어 수용성 식이섬유로 전환됨을 확인하였으며, 생산된 식이섬유소 함유 가수분해물은 기능성 식품 및 식품가공 분야에 다양하게 이용될 수 있을 것으로 판단된다.

Correlation between pr1 and pr2 Gene Content and Virulence in Metarhizium anisopliae Strains

  • Rosas-Garcia, Ninfa M.;Avalos-de-Leon, Osvaldo;Villegas-Mendoza, Jesus M.;Mireles-Martinez, Maribel;Barboza-Corona, J.E.;Castaneda-Ramirez, J.C.
    • Journal of Microbiology and Biotechnology
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    • 제24권11호
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    • pp.1495-1502
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    • 2014
  • Metarhizium anisopliae is a widely studied model to understand the virulence factors that participate in pathogenicity. Proteases such as subtilisin-like enzymes (Pr1) and trypsin-like enzymes (Pr2) are considered important factors for insect cuticle degradation. In four M. anisopliae strains (798, 6342, 6345, and 6347), the presence of pr1 and pr2 genes, as well as the enzymatic activity of these genes, was correlated with their virulence against two different insect pests. The 11 pr1 genes (A, B, C, D, E, F, G, H, I, J, and K) and pr2 gene were found in all strains. The activity of individual Pr1 and Pr2 proteases exhibited variation in time (24, 48, 72, and 96 h) and in the presence or absence of chitin as the inductor. The highest Pr1 enzymatic activity was shown by strain 798 at 48 h with chitin. The highest Pr2 enzymatic activity was exhibited by the 6342 and 6347 strains, both grown with chitin at 24 and 48 h, respectively. Highest mortality on S. exigua was caused by strain 6342 at 48 h, and strains 6342, 6345, and 6347 caused the highest mortality 7 days later. Mortality on Prosapia reached 30% without variation. The presence of subtilisin and trypsin genes and the activity of these proteases in M. anisopliae strains cannot be associated with the virulence against the two insect pests. Probably, subtilisin and trypsin enzyme production is not a vital factor for pathogenicity, but its contribution is important to the pathogenicity process.

Predicting In Sacco Rumen Degradation Kinetics of Raw and Dry Roasted Faba Beans (Vicia faba) and Lupin Seeds (Lupinus albus) by Laboratory Techniques

  • Yu, P.;Egan, A.R.;Leury, B.J.
    • Asian-Australasian Journal of Animal Sciences
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    • 제13권10호
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    • pp.1377-1387
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    • 2000
  • Two laboratory techniques: (1) an in vitro method with two procedures for measuring protein degradabilities and (2) an in vitro method with three procedures for measuring protein solubility, were investigated to determine which laboratory techniques could most accurately predict the quantity of rumen protein degradation kinetics of legume seeds after dry roasting under various conditions, in terms of (1) rumen protein disappearance ($D_j$, where j=0, 2, 4, 8, 12, 24 and 48 h incubation), (2) rumen protein effective degradability (EDCP), (3) the parameters describing rumen degradation characteristics (the soluble fraction: S, the potentially degradable fraction: D, undegradable fraction: U, lag time: T0 and the degradation rate: Kd) and (4) rumen bypass protein (BCP), which were determined by the method accepted internationally at present, in sacco nylon bag technique using the standardized Dutch method. Feeds evaluated were the raw and dry roasted whole faba (Vicia faba) beans (WFB) and whole lupin (Lupinus albus) seeds (WLS), each was dry roasted under various conditions (at 110, 130 or $150^{\circ}C$ for 15, 30 or 45 min). In vitro protein degradability ($D_1$_Auf and $D_{24}$_Auf) were determined using the modified Aufr re method by enzymatic hydrolysis for 1 h and 24 h using a protease extracted from Streptomyces griseus in a borate-phosphate buffer. In vitro protein solubility ($bf_1$_S, $bf_2$_S, $bf_3$_S) was measured in a borate-phosphate buffer with three different procedures. Results from laboratory techniques (in vitro) were correlated and linearly regressed with in sacco results. Of the three procedures of in vitro protein solubility evaluated, none of them could predict in sacco results with good precision. The highest Pearson correlation coefficient ($R^2$) was less than 0.50. Of two procedures of in vitro protein degradability studied, the $D_1$_Auf values were closely correlated with in sacco parameters: Kd, EDCP and %BCP with high R' values: 0.82, 0.85 and 0.85, respectively, and closely correlated with in sacco $D_j$ at 2, 4, 8 and 12 h rumen incubation with high $R^2$ values: 0.83, 0.91, 0.93 and 0.83, respectively. The $D_{24}$_Auf values could not predict in sacco results. The highest $R^2$ value was less then 0.40. These results indicated that in vitro protein solubility measured in borate-phosphate failed to identify differences in the rate and extent of protein degradation of legume seeds after dry roasting under various conditions and thus should not be used to predict rumen degradation, particularly for heat processed feedstuffs. But in vitro protein degradability using the modified Aufr re method by enzymatic hydrolysis for 1 h or possibly an intermediate time (>1 h and <24 h) is a promising laboratory procedure to detect effectiveness of dry roasting legume seeds on rumen protein degradation characteristics and could be used as a simple laboratory method to predict the rate and extent of protein degradation in the rumen in sacco with high accuracy. The equations to predict EDCP, Kd and BCP of dry roasted legume seeds (WLS and WFB) under various conditions are as follow: For both: EDCP (%)=-1.37+1.06*$D_1$_Auf ($R^2=0.85$, p<0.01). For both: Kd (%/h)=-21.81+0.49*$D_1$_Auf ($R^2=0.82$, p<0.01). For both: %BCP=103.37-1.07*$D_1$_Auf ($R^2=0.85$, p<0.01).

Effects of microbial enzymes on starch and hemicellulose degradation in total mixed ration silages

  • Ning, Tingting;Wang, Huili;Zheng, Mingli;Niu, Dongze;Zuo, Sasa;Xu, Chuncheng
    • Asian-Australasian Journal of Animal Sciences
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    • 제30권2호
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    • pp.171-180
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    • 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.

Pseudomonas sp. RY-1에 의한 Medium-chain-length Polyhydroxyalkanoates의 생분해 (Biodegradation of Medium-chain-length Polyhydroxyalkanoates by Pseudomonas sp. RY-1)

  • 류강은;김영백;양영기;이영하
    • 미생물학회지
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    • 제36권2호
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    • pp.84-90
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    • 2000
  • Psudomonas sp. RY-1이 생성하는 extracellular depolymerase system을 이용하여 단위체의 결가지에 서로 다른 탄소 길이와 불포와기를 함유하는 medium-chain-length polyhdroxyalkanoates (MCL-PHAs)의 생분해도를 시럼실 조건에서 조사하였다. 생분애도는 평파내지에서의 clear zone 형성, 효소 처리에 의한 고분자 현탁액의 탁도 감소 및 호흡량의 경시적 변화로 측정하였다. Pseudomonas sp. RY-1은 MCL-PHA depolymerase의 생성을 통하여 조사된 모든 종류의 MCl-PHAs를 분해할 수 있었으나, 이 효소의 생성은 쉽게 이용될수 있는 이차기질에 의해 저해받는 것으로 나타났다. MCl-PHAs의 분해율이 단위체의 탄소수가 홀수개로 구성된 고분자에 비하여 보다 높았다. 곁가지에 분포화기를 함유한 MCl-PHAs는 불포화기를 갖지 아니하는 고분자에 비하여 분해가 빠르게 이루어졌으며, 이들의 분해는 고분자의 결정화도와 밀접한 관련이 있는 것으로 나타났다.

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비스코스 레이온과 리오셀의 생분해성 (Biodegradability of Viscose Rayon and Lyocell Fibers)

  • 윤창상;박정희;강연경;임승순
    • 한국의류학회지
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    • 제29권3_4호
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    • pp.470-477
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    • 2005
  • This study was carried out to evaluate the biodegradability of viscose rayon and lyocell fibers, employing soil burial test, activated sludge test and enzymatic hydrolysis. Using X-ray analysis, crystallinity and morphology change was investigated. External changes after degradation were also observed by SEM and digital photographs. Vscose rayon fibers exhibited higher biodegadation than lyocell fibers, indicating that lower crystallinity favored the biodegradation. Among the biodegradability of lyocell fibers there was a tendency that fibers with lower crystallinity and higher moisture regain had higher values. When external changes after degradation being observed, it was shown that there were microorganisms growing on the surfaces of samples accompanying lading and weakening. From these results it was concluded that biodegradability of the specimens was most closely correlated to the moisture regain and crystallinity of fibers which reflects hydrophilicity and internal structure.

4-Chlorophenol 분해박테리아 Arthrobacter chlorophenolicus A6로부터의 monooxygenase의 복제 및 대량발현과 정제 그리고 기질분해활성도 분석 (Overexpression and Purification of Monooxygenases Cloned from Arthrobacter chlorophenolicus A6 for Enzymatic Decomposition of 4-Chlorophenol)

  • 류송정;이소라;김한승
    • 한국지하수토양환경학회지:지하수토양환경
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    • 제19권3호
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    • pp.47-55
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    • 2014
  • Arthrobacter chlorophenolicus A6 possesses several monooxygenases (CphC-I, CphC-II, and CphB) that can catalyze the transformation of 4-chlorophenol (4-CP) to hydroxylated intermediates in the initial steps of substrate metabolism. The corresponding genes of the monooxygenases were cloned, and the competent cells were transformed with these recombinant plasmids. Although CphC-II and CphB were expressed as insoluble forms, CphC-I was successfully expressed as a soluble form and isolated by purification. The specific activity of the purified CphC-I was analyzed by using 4-CP, 4-chlorocatechol (4-CC), and catechol (CAT) as substrates. The specific activities for 4-CP, 4-CC, and CAT were determined to be 0.312 U/mg, 0.462 U/mg, 0.246 U/mg, respectively. The results of this study indicated that CphC-I is able to catalyze the degradation of 4-CC and CAT in addition to 4-CP, which is a primary substrate. This research is expected to provide the fundamental information for the development of an eco-friendly biochemical degradation of aromatic hydrocarbons.