• Tribology and Lubricants
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• v.17 no.3
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• pp.171-178
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• 2001

In order to elucidate the lubricating mechanism of polyolester base oils [POEs], the wear characteristics of 27 kinds of polyolester base oils including mixed POEs were investigated. Their wear results were discussed in terms of the effect of molecular structure on wear performance and compared with those of mineral oil. In addition, the adsorption ability of POEs to reduced iron and their hydrolysis rates were measured and the effect of their molecular structures on the adsorptivity and hydrolysis rate of POEs was discussed, respectively. Finally, the lubricating mechanism anlyzed from these results of wear characteristics, adsorptivity and hydrolysis rate was proposed. That is to say, POEs are firstly adsorbed to friction surface and decomposed by hydrolysis or thermal degradation. Fatty acids obtained by degradation of POEs form adsorption film on friction surface. The larger become cohesive ability among fatty acid molecules in the adsorption film, the better gets the wear performance of POEs.

• KSBB Journal
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• v.15 no.1
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• pp.72-75
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• 2000

The hydrolysis characteristics of each fatty acid composing the fish oil by means of the lipase from Candida cylindracea was investigated. The saturated fatty acids, C14:0, C16:0 and C18:0, and the unsaturated fatty acids with one double bond, C16:1, C18:1(n-7), C18:(n-9), C20:1 and C22:1 were more easily hydrolyzed than the $\omega$-3 polyunsaturated fatty acids. when the number of carbon of the $\omega$-3 fatty acids was same but that of double bond was different, the hydrolysis of the $\omega$-3 fatty acids having lower number of double bond was more rapidly carried out. When the degree of polyunsaturation was same but the number of carbon was different, the lipase acted more rapidly upon the $\omega$-3 fatty acids with lower number of carbon. Docosahexaenoic acid(DHA) was most highly concentrated in the glyceride mixture after 120hr hydrolysis among the various $\omega$-3 polyunsaturated fatty acids. The weight percentage of DHA to the $\omega$-3 fatty acids in the fish oil was 31.87% but that in the glyceride mixture after 120hr hydrolysis was 51.89%.

• Korean Chemical Engineering Research
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• v.53 no.2
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• pp.199-204
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• 2015

Response surface methodology (RSM) in combination with a 17-run central composite design (CCD) was applied to optimize the non-catalytic hydrolysis of lard using subcritical water to produce fatty acids (FA). The effects of three variables including temperature, molar ratio of water to oil and time, and their relationship on FA content were investigated. A quadratic regression model was employed to predict the FA contents. Optimum reaction conditions for maximizing the FA content were obtained as follows: reaction temperature of $288.5^{\circ}C$, molar ratio of water to oil of 39.5 and reaction time of 29.5 min. Under the optimum conditions, the predicted and experimentally obtained FA contents were 97.06% and 96.99%, respectively.

• KSBB Journal
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• v.13 no.1
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• pp.90-95
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• 1998

Experiments on the process development for the concentration of polyunsaturated fatty acid (PUFAs) such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) from fish oil by using acyl chain specificity of Candida cylindracea lipase were performed. Five kinds of oils were hydrolyzed with Candida cylindracea lipase. Among then, Candida cylindracea lipase just had low activity on the PUFAs-rich fish oil. After the hydrolysis of fish oil, free fatty acid was removed and fatty acid components of glyceride mixtures were analyzed. When the hydrolysis was about 70%, the DHA content in the glyceride mixture was about three times more than that in the original fish oil. The EPA and stearidonic acid contents in the glyceride mixtures, however, were similar to that of the original fish oil. In this work, these results showed that the concentration process of PUFAs by using the acyl chain specificity of Candida cylindreacea lipase was effective in producing glycerides that contained a high concentration of PUFAs in good yield.

• Journal of Microbiology and Biotechnology
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• v.22 no.8
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• pp.1084-1091
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• 2012

Xylooligosaccharides are functional foods mainly produced during the hydrolysis of xylan by physical, chemical, or enzymatic methods. In this study, production of xylobiose was investigated using oil palm empty fruit bunch fiber (OPEFB) as a source material, by chemical and enzymatic methods. Xylanase-specific xylan hydrolysis followed by xylobiose production was observed. Among different xylanases, xylanase from FXY-1 released maximum xylobiose from pretreated OPEFB fiber, and this fungal strain was identified as Aspergillus terreus and subsequently deposited under the accession Number MTCC- 8661. The imperative role of lignin on xylooligosaccharides enzymatic synthesis was exemplified with the notice of xylobiose production only with delignified material. A maximum 262 mg of xylobiose was produced from 1.0 g of pretreated OPEFB fiber using FXY-1 xylanase (6,200 U/ml) at pH 6.0 and $45^{\circ}C$. At optimized environment, the yield of xylobiose was improved to 78.67 g/100 g (based on xylan in the pretreated OPEFB fiber).

• Journal of Environmental Science International
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• v.19 no.10
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• pp.1247-1256
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• 2010

Since biodiesel as bioenergy is defined as ester compounds formed by esterification of animal/vegetable oils, in this study three vegetable cooking oils (market, waste and refined waste ones) were esterified by reactions of alkali catalyst and immobilized enzyme. The fatty acid composition of the formed ester compounds was analyzed to investigate the feasibility of biodiesel production. By lipolysis (i.e, hydrolysis of Triglyceride (TG)), all three vegetable oils used in this study were found to produce Diglyceride (DG), Monoglyceride (MD) and Fatty acid ethylester (FAEE). However, the amount of produced FAEE (which can be used as an energy source) was in the increasing order of market cooking oil, waste one and refined waste one. With NaOH catalyst, FAEE was produced about 24.92, 17.63 and 11.31 % for the respective oils while adding Lipozyme TL produced FAEE about 43.54, 38.16 and 24.47 %, respectively. This indicates that enzyme catalyst is more effective than alkali one for transesterification. In addition, it was found that the composition of fatty acids produced by hydrolysis of TG was unchanged with alkali and immobilized enzyme reactions. Thus it can be expected that stable conditions remain in the course of mixing with gasoline whose composition is similar to that of the fatty acids.

• Microbiology and Biotechnology Letters
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• v.19 no.4
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• pp.377-382
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• 1991

Reef tallow was hydrolyzed with lipase under the conditions of liquid state and solid state. Lipase OF 360 was used for that purpose, and the lipase had the maximum activity when the olive oil was used as a substrate at pH 6 and $37^{\circ}C$. Beef tallow was dispersed by an agitator to perform a liquid enzymatic reaction. Water content, reaction temperature, and enzyme amount were varied as parameters affecting hydrolysis percentage. Ninety three percents of tallow were hydrolyzed at the following conditions: water content 80% w/w, temperature $37^{\circ}C$, and enzyme amount 200 unitlg tallow. In order to conduct a solid phase enzymatic reaction, sonication was employed for pretreating tallow with the enzyme solution. Molten tallow was sonified with the enzyme solution, and solidified by lowering temperature. And then hydrolysis reaction proceeded at $30^{\circ}C$. Sonication intensity and time were varied to control hydrolysis percentage. Optimum values of the intensity and the time were found to exist since the hydrolysis percentage did not increase further according to the increases of the intensity and the time.

• Journal of the Korean Wood Science and Technology
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• v.48 no.5
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• pp.651-665
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• 2020

Hydrolysis of biomass for the production of fermentable sugar can be improved by the addition of surfactants. In pulp and paper mills, lignin, which is a by-product of the pulping process, can be utilized as a fine chemical. In the hydrolysis process, lignin is one of the major inhibitors of the enzymatic breakdown cellulose into sugar monomer. Therefore, the conversion of lignin into a biosurfactant offers the opportunity to solve the waste problem and improve hydrolysis efficiency. In this study, lignin derivatives, a biosurfactant, was applied to enzymatic hydrolysis of various lignocellulosic biomass. This Biosurfactant can be prepared by reacting lignin with a hydrophilic polymer such as polyethylene glycol diglycidylethers (PEDGE). In this study, the effect of biosurfactants on the enzymatic hydrolysis of pretreated sweet sorghum bagasse (SSB), oil palm empty fruit bunch, and sugarcane trash with different lignin contents was investigated. The results show that lignin derivatives improve the enzymatic hydrolysis of the pretreated biomass with low lignin content, however, it has less influence on the enzymatic hydrolysis of other pretreated biomass with lignin content higher than 10% (w/w). The use of biosurfactant on SSB kraft pulp can increase the sugar yield from 45.57% to 81.49%.

• Journal of Marine Bioscience and Biotechnology
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• v.1 no.4
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• pp.311-316
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• 2006

Enzymatic ethanolysis of fish oil with immobilized lipase was investigated for reducing the free fatty acid contents and enhancing the function of fish oil. Ethanolysis reactions were carried out in erlenmeyer flask (25ml) containing a mixture of squid viscera oil and 99.9% ethanol using 1% (based on w/w squid viscera oil) immobilized lipase. The reaction mixtures were incubated at $50^{\circ}C$ and shaken at 100rpm. Ethanol was added into the mixture by stepwise addition method of Shinmada[9]. Measurement of free fatty acid molar amounts was studied by Acid Value. Tendency of oil variation during transesterification was studied by TLC method. Enzymatic ethanolysis composed diglyceride, monoglyceride and fatty acid ethyl ester with reducing free fatty acid contents. Also, selective ethanolysis by Lipozyme TL-IM and Lipozyme RM-IM mostly did not react at the sn-2 position of squid viscera oil. Lipozyme RM-IM was more suitable enzyme to reduce the free fatty acid contents by ethanolysis than Lipozyme TL-IM. Squid viscera oil was transformed into suitable properties (5 in Acid Value) for functional fish oil production.

• Journal of Environmental Science International
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• v.19 no.1
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• pp.97-103
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• 2010

The biodegradable oil absorption resin was prepared by the suspension polymerization of the modified starch and 2-ethylhexyl acrylate (2-EHA). The highest oil-absorption capacity of B-PEHA prepared showed at the condition of the modified starch content of 10 g and ethyleneglycol dimethacrylate (EGDMA) of 0.133 wt%. Its maximum oil absorption capacity per g of oil absorber was chloroform 30.88 g, toluene 19.75 g, xylene 18.78 g, tetrahydofuran (THF) 15.96 g, octane 11.43 g, hexane 9.5 g diesel oil 12.80 g, and kerosene 13.79 g, respectively. The biodegradation of poly-2-ethylhexylacrylate (B-PEHA) determined by enzymatic hydrolysis showed approximately 17~20%. The results showed that the preparation of the biodegradable oil absorption resin is available using the modified starch.