• Biotechnology and Bioprocess Engineering:BBE
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• v.11 no.1
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• pp.26-31
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• 2006

The saccharogenic liquid (SFW) obtained by the enzymatic saccharification of food wastes was used as a medium for production of bacterial cellulose (BC). The enzymatic saccharification of food wastes was carried out by the cultivation supernatant of Trichoderma harziaum FJ1 culture. Acetobacter xylinum KJ1 was employed for the BC production culture. The physical properties, such as polymerization, crystallinity, Young's modulus, and tensile strength, of BCs produced by three culture methods: the static cultures using HS (Hestrin-Schramm) as a reference medium (A) or the SFW medium (B), the shaking culture (C) or the air circulation culture (D) using the SFW medium, were investigated. The degrees of polymerization of BCs produced under the different culture conditions (A-D) showed 11000, 9500, 8500, and 9200, respectively. Young's modulus was 4.15, 5.0, 4.0, and 4.6 GPa, respectively. Tensile strength was 124, 200, 80, and 184 MPa, respectively. All of the BC had a form of cellulose I representing pure cellulose. In the case of the shaking culture, the degree of crystallinity was 51.2%, the lowest degree. Under the other culturing conditions, the trend should remain in the range of 89.7-84%. Overall, the physical properties of BC produced from SFW were similar to those of BC from HS medium, a commercial complex medium, and BC production by the air circulation culture mode brought more favorable results in terms of the physical properties and its ease of scale-up. Therefore, it is expected that a new BC production method, like air circulation culture using SFW, would contribute greatly to BC-related manufacturing.

• Journal of the East Asian Society of Dietary Life
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• v.5 no.3
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• pp.359-370
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• 1995

Kimchi is a traditional fermented vegetable in Korea. It has unique taste and flavor due to the variability of raw vegetable, subingredient and their ratio of combination. Fermentation method have very critical effect on these charicteristics. Overall taste of Kimchi is also influenced by texture. In this paper, the changes in texture of Kimchis were reviewed related to pectic substance, enzymatic activities and other chemical changes during the fermentation of Kimchi. Moreover, treatments to prevent softening of Kimchi texture such as preheating, CaCl$_2$ addition, their combination effect and chitosan addition were summarized from the literatures.

• BMB Reports
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• v.32 no.6
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• pp.541-546
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• 1999

When we compared the chitinase activity of various plant sources using colorimetric or active gel-staining assay methods, the specific activity of pumpkin leaves was the highest among the samples we analyzed. The highly active chitinase from pumpkin leaves (designated PL-ChtIII) was purified to homogeneity using affinity chitin gel and HPLC Mono-Q anion-exchange cloumn chromatographies. In contrast to other members of the class III chitinase family, PL-ChtIII showed a strong binding affinity to the regenerated chitin gel column. The apparent molecular weight of PL-ChtIII was estimated to be 29 kDa on SDS-PAGE gel, while its optimum pH and temperature were shown to be pH 6.0 and $60^{\circ}C$, respectively. Analyzing the reaction products of PL-ChtIII with swollen chitin as substrate, the dimer and tetramer of N-acetylglucosamine were produced as major products in the first hour of the enzymatic reaction along with a small amount of monomers and trimers. As the reaction time increased, dimeric N-acetylglucosamine became the predominant form of reaction product.

• Microbiology and Biotechnology Letters
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• v.15 no.5
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• pp.312-318
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• 1987

The apparent Michaelis constant Km of extracellular adenine deaminase from Streptomyces sp. J-350P was 5.8$\times$10$^{-5}$M. The activation energy or the enzyme was calculated from Arrhenius plots for adenine and the value was 3.13 Kcal/mole. The purine analogues, 6-chloropurine, 2,6-diaminopurine, 6-bromopurine, 4-aminopyrazolo[3,4-d] pyrimidine, 6-iodopurine, and 8-bromoadenine were substrates for the enzyme. 6-Dimethylaminopurine was a competitive inhibitor of the enzyme. The enzyme was inhibited by 0.1mM of Fe$^{3+}$, Ag+, and Hg$^{2+}$ and 1 mM of $\alpha$, $\alpha$＇-dipyridyl, Penta-chiorophenol, and p-chloromercuribenzoate.

• Microbiology and Biotechnology Letters
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• v.41 no.1
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• pp.1-7
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• 2013

Ionic liquids (ILs) have been widely recognized as environmentally benign solvents. Their unique properties, including negligible vapor pressure, non-flammability, a wide liquid range and their tunable physicochemical properties by proper selection of cations and anions, make them attractive green solvents in a variety of fields such as organic synthesis/catalysis, extraction/ separation, and electrochemistry, amongst others. In this paper, the recent technological developments and their prospects in the application of ILs in microbiology and biochemical engineering, including enzymatic reactions, protein folding/refolding and biomass dissolution, are discussed.

• Bulletin of the Korean Chemical Society
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• v.34 no.10
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• pp.2973-2977
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• 2013

In this study, we developed a liquid crystal (LC)-based optical sensor for monitoring enzymatic activity through orientational changes in liquid crystals (LCs) coupled to the properties of a poly-${\small{L}}$-lysine (PLL)-based polymeric membrane. We prepared a PLL-based polymeric membrane at the planar interface between the thermotropic liquid crystal and aqueous phases. The PLL-based polymeric membrane was obtained by contacting the PLL solution with water immiscible LCs, 4-cyano-4'-pentyl-biphenyl (5CB) doped with adipoyl chloride. We then investigated the membrane properties by examining the permeability of the membrane to phospholipids, 1,2-didodecanoyl-rac-glycero-3-phosphocholine (DLPC). The permeability of the membrane to transport phospholipids was monitored through the orientational transition of 5CB in contact with the dispersions of DLPC. Since trypsin can enzymatically catalyze the hydrolysis of PLL, we incubated an aqueous trypsin solution with the membrane for 2 h at room temperature to cause an increase in the permeability of the polymeric membrane to DLPC. As a result, a bright to dark optical shift of LCs was observed, which implied that an enzymatic reaction between trypsin and PLL-based membrane occurred. Two control experiments using chymotrypsin and bovine serum albumin (BSA) revealed no sign of improved permeability based on the orientational transition of LCs.

• Korean Journal of Microbiology
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• v.28 no.3
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• pp.229-235
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• 1990

A rapid and sensitive method to detect the extracellular enzymatic activity of bacteria colonies grown on agar plates is described. Selective agar media supplemented with protein, starch, chitin, Tween-80, etc. are conventionally used to detect biochemical properties of bacteria. It has been experimentally demonstrated with bacteria pure cultures that fluorogenic Methylumbelliferyl (MUF)-substrates are excellent substrate analogues for normally occurring polymers. Based on MUF-substrate hydrolysis the new method provides reliable qualitative estimates of extracellular enzymatic properties of bacteria within minutes using pure cultures as well as agar p;ates prepared for colony counts. Extracellular enzyme activities of heterotrophic bacteria from freshwater ecosystems and marine sediment using this method are discussed.

• Journal of the Korean Society of Clothing and Textiles
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• v.37 no.8
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• pp.1107-1116
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• 2013

This study examined the use of cutinase and lipase to process cotton/polyester blend fabric. Optimum treatment conditions for cutinase and lipase were investigated for cotton/polyester blend fabric. The properties of enzyme-treated fabrics were evaluated and compared in optimal treatment conditions. In addition, the possibility to provide an enzymatic finishing on blend fabrics using mixed enzymes in a two-step process were studied. The weight loss of cotton/polyester blend fabrics with Triton X-100 was 0.8% and the dyeing property of blend fabrics with calcium chloride increased by a factor of 1.2. The use of two enzymes in combination with cutinase and lipase in the presence of auxiliaries resulted in a cotton/polyester blend fabric weight loss of 0.8%. In addition, the dyeing properties of cotton/polyester blend fabrics improved by a factor of 1.5 and the moisture regain of cotton/polyester blend fabrics improved by a factor of 1.16. However, no marked loss was observed in tensile strength. The surface morphology of cotton/polyester blend fabrics is modified through a two-enzyme treatment. The treatment of cotton/polyester blend fabrics with cutinase and lipase maintains cotton strength and improves the moisture regain of polyester fabrics.

• Journal of the Korean Wood Science and Technology
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• v.52 no.2
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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.

• Korean journal of food and cookery science
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• v.13 no.4
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• pp.390-395
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• 1997

The inhibitory effects of cereal extracts and concentrates from barley, waxy rice flours and malt on enzymatic browning were measured using apple polyphenol oxidase (PPO). Malt concentrate showed the largest inhibitory effect on PPO among all. The relationship between the properties of malt concentrate such as browning intensity and reducing power and their inhibitory effect on PPO was also studied. As the heating time increased, the browning intensity and the reducing power of malt concentrates were increased, while PPO activities were decreased. Inhibitory effect of malt concentrates on PPO increased with heating time and their concentration. L-value and compression force of the apple slices dipped in malt concentrate decreased by 6.9% and 14.3%, respectively, showing the smallest changes compared with raw and water-dipped apple slices during cold storage for 9 days. These results suggest that malt concentrate can be a potential source for the control of enzymatic browning.