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Woo-Jin Chang,Jung Wook Hwang,Joo-Hyung Choi,최범준,이규도,이상우,구윤모 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.1
We have characterized micro-droplet generation using water immiscible hexafluorophosphate ([PF6])- and bis(trifluoromethylsulfonyl)imide ([Tf2N])-based room temperature ionic liquids (RTILs). The interfacial tension between total 7 RTILs and phosphate buffered saline (PBS) was measured using a tensiometer for the first time. PBS is one of the most commonly used buffer solutions in cell-related researches. The measured interfacial tension ranges from 8.51 to 11.62 and from 9.56 to 13.19 for [Tf2N]- and [PF6]-based RTILs, respectively. The RTILs micro-droplets were generated in a microfluidic device. The micro-droplet size and generation frequency were determined based on continuous monitoring of light transmittance at the interface in microchannel. The size of RTIL micro-droplets was inversely proportional to the increase of PBS solution flow rate and RTILs hydrophobicity, while droplet generation frequency was proportional to those changes. The measured size of RTILs droplets ranged from 0.6 to 10.5 nl, and from 1.0 to 17.1 nl for [Tf2N]- and [PF6]-based RTILs, respectively. The measured frequency of generated RTILs droplets ranged from 2.3 to 37.2 droplet/min, and from 2.7 to 17.1 droplet/min for [Tf2N]- and [PF6]-based RTILs, respectively. The capillary numbers were calculated depending on the RTILs, and ranged from 0.51×10−3 to 1.06×10−3 and from 5.00×10−3 to 8.65×10−3, for [Tf2N]- and [PF6]-based RTILs, respectively. The interfacial tension between RTILs and PBS will contribute to developing bioprocesses using immiscible RTILs. Also, the RTILs micro-droplets will enable the high-throughput monitoring of various biological and chemical reactions using RTILs as new reaction media.
Enhanced stability of Candida antarctica lipase B in ionic liquids
구윤모,하성호,이상현,Woo-Jin Chang,Dung Thanh Dang,Min Sik Kwon,Yong Jae Yu,Il Suk Byun 한국화학공학회 2008 Korean Journal of Chemical Engineering Vol.25 No.2
The activity and stability of lipase from Candida antarctica were investigated in the kinetic resolution of (R,S)-1-phenylethanol with vinyl acetate using ionic liquids (ILs) as reaction media. Among ILs tested, the highest activity of lipase was observed in [Edmim][Tf2N]. In hydrophobic ILs such as [Edmim][Tf2N], [Emim][Tf2N] and [Pmim] [PF6], lipase could retain its activity after 5 times reuse, while the activity of lipase in hydrophilic ILs and organic solvents was drastically decreased. The activities of lipase in [Edmim][Tf2N], [Emim][Tf2N] and [Pmim][PF6] were also well maintained after 1 day incubation at 80 oC. The lipase suspended in [Edmim][Tf2N] could be successfully reused 6 times without loss of activity
생물화공 , 에너지 / 환경 : Poly ( 2-ethyl-2-oxazoline ) / poly ( acrylic acid ) 계의 수소결합 특성 및 이용
김진희(Jin Hee Kim),장우진(Woo Jin Chang),구윤모(Yoon Mo Koo) 한국화학공학회 2001 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.39 No.4
The properties of hydrogen bonding between poly(2-ethyl-2-oxazoline)[PEOx] and poly(acrylic acid)[PAA] were investigated. PEOx and PAA formed stable complexes and precipitated due to hydrogen bonding between hydrogen of PAA and oxygen of PEOx in acidic conditions(below pH 4.3). Optimum reaction ratio of PEOx and PAA was determined as mass ratio 1 : 1.5 for applications in aqueous two phase system. The mixtures of the polymers formed aqueous two phase system with dextran solution after breaking hydrogen bonding. This properties can be used for the recovery of a target product.