TY  - JOUR
A1  - Al-Kaidy, Huschyar
A1  - Tippkötter, Nils
T1  - Superparamagnetic hydrophobic particles as shell material for digital microfluidic droplets and proof-of-principle reaction assessments with immobilized laccase
JF  - Engineering in Life Sciences
N2  - In the field of biotechnology and molecular biology, the use of small liquid volumes has significant advantages. In particular, screening and optimization runs with acceptable amounts of expensive and hardly available catalysts, reagents, or biomolecules are feasible with microfluidic technologies. The presented new microfluidic system is based on the inclusion of small liquid volumes by a protective shell of magnetizable microparticles. Hereby, discrete aqueous microreactor drops with volumes of 1–30 μL can be formed on a simple planar surface. A digital movement and manipulation of the microreactor is performed by overlapping magnetic forces. The magnetic forces are generated by an electrical coil matrix positioned below a glass plate. With the new platform technology, several discrete reaction compartments can be moved simultaneously on one surface. Due to the magnetic fields, the reactors can even be merged to initiate reactions by mixing or positioned above surface-immobilized catalysts and then opened by magnetic force. Comparative synthesis routes of the magnetizable shell particles and superhydrophobic glass slides including their performance and stability with the reaction platform are described. The influence of diffusive mass transport during the catalyzed reaction is discussed by evaluation finite element model of the microreactor. Furthermore, a first model dye reaction of the enzyme laccase has been established.
Y1  - 2016
U6  - http://dx.doi.org/10.1002/elsc.201400124
VL  - 16
IS  - 3
SP  - 222
EP  - 230
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Roth, Jasmine
A1  - Tippkötter, Nils
T1  - Evaluation of lignocellulosic material for butanol production using enzymatic hydrolysate medium
JF  - Cellulose Chemistry and Technology
N2  - Butanol is a promising gasoline additive and platform chemical that can be readily produced via acetone-butanolethanol (ABE) fermentation from pretreated lignocellulosic materials. This article examines lignocellulosic material from beech wood for ABE fermentation, using Clostridium acetobutylicum. First, the utilization of both C₅₋ (xylose) and C₆₋ (glucose) sugars as sole carbon source was investigated in static cultivation, using serum bottles and synthetic medium. The utilization of pentose sugar resulted in a solvent yield of 0.231 g·g_sugar⁻¹, compared to 0.262 g·g_sugar⁻¹ using hexose. Then, the Organosolv pretreated crude cellulose fibers (CF) were enzymatically decomposed, and the resulting hydrolysate medium was analyzed for inhibiting compounds (furans, organic acids, phenolics) and treated with ionexchangers for detoxification. Batch fermentation in a bioreactor using CF hydrolysate medium resulted in a total solvent yield of 0.20 gABE·g_sugar⁻¹.
Y1  - 2016
VL  - 50
IS  - 3-4
SP  - 405
EP  - 410
PB  - Editura Academiei Romane
CY  - Bukarest
ER  - 
TY  - JOUR
A1  - Rösch, C.
A1  - Kratz, F.
A1  - Hering, T.
A1  - Trautmann, S.
A1  - Umanskaya, N.
A1  - Tippkötter, Nils
A1  - Müller-Renno, C.M.
A1  - Ulber, R.
A1  - Hannig, M.
A1  - Ziegler, C.
T1  - Albumin-lysozyme interactions: cooperative adsorption on titanium and enzymatic activity
JF  - Colloids and Surfaces B: Biointerfaces
N2  - The interplay of albumin (BSA) and lysozyme (LYZ) adsorbed simultaneously on titanium was analyzed by gel electrophoresis and BCA assay. It was found that BSA and lysozyme adsorb cooperatively. Additionally, the isoelectric point of the respective protein influences the adsorption. Also, the enzymatic activity of lysozyme and amylase (AMY) in mixtures with BSA was considered with respect to a possible influence of protein-protein interaction on enzyme activity. Indeed, an increase of lysozyme activity in the presence of BSA could be observed. In contrast, BSA does not influence the activity of amylase.
Y1  - 2016
U6  - http://dx.doi.org/10.1016/j.colsurfb.2016.09.048
VL  - 149
IS  - 1
SP  - 115
EP  - 121
PB  - Elsevier
CY  - Amsterdam
ER  -