@article{ZhangBramskiTutusetal.2019,
  author    = {Zhang, Shuhao and Bramski, Julia and Tutus, Murat and Pietruszka, J{\"o}rg and B{\"o}ker, Alexander and Reinicke, Stefan},
  title     = {A Biocatalytically Active Membrane Obtained from Immobilization of 2-Deoxy-D-ribose-5-phosphate Aldolase on a Porous Support},
  series = {ACS applied materials \& interfaces},
  volume    = {11},
  journal   = {ACS applied materials \& interfaces},
  number    = {37},
  publisher = {American Chemical Society},
  address   = {Washington},
  issn      = {1944-8244},
  doi       = {10.1021/acsami.9b12029},
  pages     = {34441 -- 34453},
  year      = {2019},
  abstract  = {Aldol reactions play an important role in organic synthesis, as they belong to the class of highly beneficial C-C-linking reactions. Aldol-type reactions can be efficiently and stereoselectively catalyzed by the enzyme 2-deoxy-D-ribose-5-phosphate aldolase (DERA) to gain key intermediates for pharmaceuticals such as atorvastatin. The immobilization of DERA would open the opportunity for a continuous operation mode which gives access to an efficient, large-scale production of respective organic intermediates. In this contribution, we synthesize and utilize DERA/polymer conjugates for the generation and fixation of a DERA bearing thin film on a polymeric membrane support. The conjugation strongly increases the tolerance of the enzyme toward the industrial relevant substrate acetaldehyde while UV-cross-linkable groups along the conjugated polymer chains provide the opportunity for covalent binding to the support. First, we provide a thorough characterization of the conjugates followed by immobilization tests on representative, nonporous cycloolefinic copolymer supports. Finally, immobilization on the target supports constituted of polyacrylonitrile (PAN) membranes is performed, and the resulting enzymatically active membranes are implemented in a simple membrane module setup for the first assessment of biocatalytic performance in the continuous operation mode using the combination hexanal/acetaldehyde as the substrate.},
  language  = {en}
}
@article{ReinickeFischerBramskietal.2019,
  author    = {Reinicke, Stefan and Fischer, Thilo and Bramski, Julia and Pietruszka, J{\"o}rg and B{\"o}ker, Alexander},
  title     = {Biocatalytically active microgels by precipitation polymerization of N-isopropyl acrylamide in the presence of an enzyme},
  series = {RSC Advances},
  volume    = {9},
  journal   = {RSC Advances},
  number    = {49},
  publisher = {Royal Society of Chemistry},
  address   = {Cambridge},
  issn      = {2046-2069},
  doi       = {10.1039/c9ra04000e},
  pages     = {28377 -- 28386},
  year      = {2019},
  abstract  = {We present a novel protocol for the synthesis of enzymatically active microgels. The protocol is based on the precipitation polymerization of N-isopropylacrylamide (NIPAm) in the presence of an enzyme and a protein binding comonomer. A basic investigation on the influence of different reaction parameters such as monomer concentration and reaction temperature on the microgel size and size distribution is performed and immobilization yields are determined. Microgels exhibiting hydrodynamic diameters between 100 nm and 1 mu m and narrow size distribution could be synthesized while about 31-44\% of the enzyme present in the initial reaction mixture can be immobilized. Successful immobilization including a verification of enzymatic activity of the microgels is achieved for glucose oxidase (GOx) and 2-deoxy-d-ribose-5-phosphate aldolase (DERA). The thermoresponsive properties of the microgels are assessed and discussed in the light of activity evolution with temperature. The positive correlation of enzymatic activity with temperature for the GOx containing microgel originates from a direct interaction of the enzyme with the PNIPAm based polymer matrix whose magnitude is highly influenced by temperature.},
  language  = {en}
}
@article{ZhangBisterfeldBramskietal.2017,
  author    = {Zhang, Shuhao and Bisterfeld, Carolin and Bramski, Julia and Vanparijs, Nane and De Geest, Bruno G. and Pietruszka, J{\"o}rg and B{\"o}ker, Alexander and Reinicke, Stefan},
  title     = {Biocatalytically Active Thin Films via Self-Assembly of 2-Deoxy-D-ribose-5-phosphate Aldolase-Poly(N-isopropylacrylamide) Conjugates},
  series = {Bioconjugate chemistry},
  volume    = {29},
  journal   = {Bioconjugate chemistry},
  number    = {1},
  publisher = {American Chemical Society},
  address   = {Washington},
  issn      = {1043-1802},
  doi       = {10.1021/acs.bioconjchem.7b00645},
  pages     = {104 -- 116},
  year      = {2017},
  abstract  = {2-Deoxy-D-ribose-5-phosphate aldolase (DERA) is a biocatalyst that is capable of converting acetaldehyde and a second aldehyde as acceptor into enantiomerically pure mono- and diyhydroxyaldehydes, which are important structural motifs in a number of pharmaceutically active compounds. However, substrate as well as product inhibition requires a more-sophisticated process design for the synthesis of these motifs. One way to do so is to the couple aldehyde conversion with transport processes, which, in turn, would require an immobilization of the enzyme within a thin film that can be deposited on a membrane support. Consequently, we developed a fabrication process for such films that is based on the formation of DERA-poly(N-isopropylacrylamide) conjugates that are subsequently allowed to self-assemble at an air-water interface to yield the respective film. In this contribution, we discuss the conjugation conditions, investigate the interfacial properties of the conjugates, and, finally, demonstrate a successful film formation under the preservation of enzymatic activity.},
  language  = {en}
}