@article{ThielTippkoetterSucketal.2013, author = {Thiel, Alexander and Tippk{\"o}tter, Nils and Suck, Kirstin and Sohling, Ulrich and Ruf, Friedrich and Ulber, Roland}, title = {New zeolite adsorbents for downstream processing of polyphenols from renewable resources}, series = {Engineering in Life Sciences}, volume = {13}, journal = {Engineering in Life Sciences}, number = {3}, publisher = {Wiley}, address = {Weinheim}, doi = {10.1002/elsc.201200188}, pages = {239 -- 246}, year = {2013}, abstract = {Commercial materials with polyvinylpolypyrrolidone and polymeric amberlites (XAD7HP, XAD16) are commonly used for the adsorptive downstream processing of polyphenols from renewable resources. In this study, beta-zeolite-based adsorbent systems were examined, and their properties were compared to organic resins. Batch adsorption experiments were conducted with synthetic solutions of major polyphenols. Adsorption isotherms and desorption characteristics of individual adsorbent were determined based on these results. Maximum adsorption capacities were calculated using the Langmuir model. For example, the zeolites had capacities up to 203.2 mg/g for ferulic acid. To extend these results to a complex system, additional experiments were performed on rapeseed meal and wheat seed extracts as representative renewable resources. HPLC analysis showed that with 7.5\% w/v, which is regarded as the optimum amount of zeolites, zeolites A and B could bind 100\% of the major polyphenols as well as release polyphenols at high yields. Additionally, regeneration experiments were performed with isopropyl alcohol at 99°C to evaluate how zeolites regenerate under mild conditions. The results showed only a negligible loss of adsorption capacity and no loss of desorption capacity. In summary, it was concluded that beta-zeolites were promising adsorbents for developing new processes to isolate polyphenols from renewable resources.}, language = {en} } @article{TippkoetterDuweWiesenetal.2014, author = {Tippk{\"o}tter, Nils and Duwe, Anna-Maria and Wiesen, Sebastian and Sieker, Tim and Ulber, Roland}, title = {Enzymatic hydrolysis of beech wood lignocellulose at high solid contents and its utilization as substrate for the production of biobutanol and dicarboxylic acids}, series = {Bioresource Technology}, volume = {167}, journal = {Bioresource Technology}, publisher = {Elsevier}, address = {Amsterdam}, doi = {10.1016/j.biortech.2014.06.052}, pages = {447 -- 455}, year = {2014}, abstract = {The development of a cost-effective hydrolysis for crude cellulose is an essential part of biorefinery developments. To establish such high solid hydrolysis, a new solid state reactor with static mixing is used. However, concentrations >10\% (w/w) cause a rate and yield reduction of enzymatic hydrolysis. By optimizing the synergetic activity of cellulolytic enzymes at solid concentrations of 9\%, 17\% and 23\% (w/w) of crude Organosolv cellulose, glucose concentrations of 57, 113 and 152 g L⁻¹ are reached. However, the glucose yield decreases from 0.81 to 0.72gg⁻¹ at 17\% (w/w). Optimal conditions for hydrolysis scale-up under minimal enzyme addition are identified. As result, at 23\% (w/w) crude cellulose the glucose yield increases from 0.29 to 0.49gg⁻¹. As proof of its applicability, biobutanol, succinic and itaconic acid are produced with the crude hydrolysate. The potential of the substrate is proven e.g. by a high butanol yield of 0.33gg⁻¹.}, language = {en} } @article{TippkoetterWollnySucketal.2014, author = {Tippk{\"o}tter, Nils and Wollny, Steffen and Suck, Kirstin and Sohling, Ulrich and Ruf, Friedrich and Ulber, Roland}, title = {Recycling of spent oil bleaching earth as source of glycerol for the anaerobic production of acetone, butanol, and ethanol with Clostridium diolis and lipolytic Clostridium lundense}, series = {Engineering in Life Sciences}, volume = {14}, journal = {Engineering in Life Sciences}, number = {4}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1618-2863}, doi = {10.1002/elsc.201300113}, pages = {425 -- 432}, year = {2014}, abstract = {A major part of edible oil is subjected to bleaching procedures, primarily with minerals applied as adsorbers. Their recycling is currently done either by regaining the oil via organic solvent extraction or by using the spent bleaching earth (SBE) as additive for animal feed, etc. As a new method, the reutilization of the by-product SBE for the microbiologic formation of acetone, butanol, and ethanol (ABE) is presented as proof-of-concept. The SBE was taken from a palm oil cleaning process. The recycling concept is based on the application of lipolytic clostridia strains. Due to considerably long fermentation times, co-fermentation with Candida rugosa and enzymatic hydrolyses of the bound oil with a subsequent clostridia fermentation are shown as alternative routes. Anaerobic fermentations under comparison of different clostridia strains were performed with glycerol media, enzymatically hydrolyzed palm oil and SBE. Solutes, side product compositions and productivities were quantified via HPLC. A successful production of ABE solutes from SBE has been done with a yield of 0.15 g butanol per gram of bound glycerol. Thus, the biotechnological recycling of the waste stream is possible in principle. Inhibition of the substrate suspension has been observed. A chromatographic ion-exchange of substrates increased the biomass concentration.}, language = {en} } @article{BaeckerDellePoghossianetal.2011, author = {B{\"a}cker, Matthias and Delle, L. and Poghossian, Arshak and Biselli, Manfred and Zang, Werner and Wagner, P. and Sch{\"o}ning, Michael Josef}, title = {Electrochemical sensor array for bioprocess monitoring}, series = {Electrochimica Acta (2011)}, volume = {56}, journal = {Electrochimica Acta (2011)}, number = {26}, publisher = {Elsevier}, address = {Amsterdam}, pages = {9673 -- 9678}, year = {2011}, language = {en} } @article{BaeckerRaueSchusseretal.2012, author = {B{\"a}cker, Matthias and Raue, Markus and Schusser, Sebastian and Jeitner, C. and Breuer, L. and Wagner, P. and Poghossian, Arshak and F{\"o}rster, Arnold and Mang, Thomas and Sch{\"o}ning, Michael Josef}, title = {Microfluidic chip with integrated microvalves based on temperature- and pH-responsive hydrogel thin films}, series = {Physica Status Solidi (a)}, volume = {209}, journal = {Physica Status Solidi (a)}, number = {5}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1862-6319}, doi = {10.1002/pssa.201100763}, pages = {839 -- 845}, year = {2012}, abstract = {Two types of microvalves based on temperature-responsive poly(N-isopropylacrylamide) (PNIPAAm) and pH-responsive poly(sodium acrylate) (PSA) hydrogel films have been developed and tested. The PNIPAAm and PSA hydrogel films were prepared by means of in situ photopolymerization directly inside the fluidic channel of a microfluidic chip fabricated by combining Si and SU-8 technologies. The swelling/shrinking properties and height changes of the PNIPAAm and PSA films inside the fluidic channel were studied at temperatures of deionized water from 14 to 36 °C and different pH values (pH 3-12) of Titrisol buffer, respectively. Additionally, in separate experiments, the lower critical solution temperature (LCST) of the PNIPAAm hydrogel was investigated by means of a differential scanning calorimetry (DSC) and a surface plasmon resonance (SPR) method. Mass-flow measurements have shown the feasibility of the prepared hydrogel films to work as an on-chip integrated temperature- or pH-responsive microvalve capable to switch the flow channel on/off.}, language = {en} } @incollection{DuongSeifarthTemizArtmannetal.2018, author = {Duong, Minh Tuan and Seifarth, Volker and Temiz Artmann, Ayseg{\"u}l and Artmann, Gerhard and Staat, Manfred}, title = {Growth Modelling Promoting Mechanical Stimulation of Smooth Muscle Cells of Porcine Tubular Organs in a Fibrin-PVDF Scaffold}, series = {Biological, Physical and Technical Basics of Cell Engineering}, booktitle = {Biological, Physical and Technical Basics of Cell Engineering}, editor = {Artmann, Gerhard and Temiz Artmann, Ayseg{\"u}l and Zhubanova, Azhar A. and Digel, Ilya}, publisher = {Springer}, address = {Singapore}, isbn = {978-981-10-7904-7}, doi = {10.1007/978-981-10-7904-7_9}, pages = {209 -- 232}, year = {2018}, abstract = {Reconstructive surgery and tissue replacements like ureters or bladders reconstruction have been recently studied, taking into account growth and remodelling of cells since living cells are capable of growing, adapting, remodelling or degrading and restoring in order to deform and respond to stimuli. Hence, shapes of ureters or bladders and their microstructure change during growth and these changes strongly depend on external stimuli such as training. We present the mechanical stimulation of smooth muscle cells in a tubular fibrin-PVDFA scaffold and the modelling of the growth of tissue by stimuli. To this end, mechanotransduction was performed with a kyphoplasty balloon catheter that was guided through the lumen of the tubular structure. The bursting pressure was examined to compare the stability of the incubated tissue constructs. The results showed the significant changes on tissues with training by increasing the burst pressure as a characteristic mechanical property and the smooth muscle cells were more oriented with uniformly higher density. Besides, the computational growth models also exhibited the accurate tendencies of growth of the cells under different external stimuli. Such models may lead to design standards for the better layered tissue structure in reconstructing of tubular organs characterized as composite materials such as intestines, ureters and arteries.}, language = {en} } @article{AlKaidyDuweHusteretal.2015, author = {Al-Kaidy, Huschyar and Duwe, Anna and Huster, Manuel and Muffler, Kai and Schlegel, Christin and Tim, Sieker and Stadtm{\"u}ller, Ralf and Tippk{\"o}tter, Nils and Ulber, Roland}, title = {Biotechnology and bioprocess engineering - from the first ullmann's article to recent trends}, series = {ChemBioEng Reviews}, volume = {2}, journal = {ChemBioEng Reviews}, number = {3}, publisher = {Wiley}, address = {Weinheim}, doi = {10.1002/cben.201500008}, pages = {175 -- 184}, year = {2015}, abstract = {For several thousand years, biotechnology and its associated technical processes have had a great impact on the development of mankind. Based on empirical methods, in particular for the production of foodstuffs and daily commodities, these disciplines have become one of the most innovative future issues. Due to the increasing detailed understanding of cellular processes, production strains can now be optimized. In combination with modern bioprocesses, a variety of bulk and fine chemicals as well as pharmaceuticals can be produced efficiently. In this article, some of the current trends in biotechnology are discussed.}, language = {en} } @article{PothMonzonTippkoetteretal.2011, author = {Poth, Sebastian and Monzon, Magaly and Tippk{\"o}tter, Nils and Ulber, Roland}, title = {Lignocellulosic biorefinery: Process integration of hydrolysis and fermentation (SSF process)}, series = {Holzforschung}, volume = {65}, journal = {Holzforschung}, number = {5}, publisher = {De Gruyter}, address = {Berlin}, pages = {633 -- 637}, year = {2011}, abstract = {The aim of the present work is the process integration and the optimization of the enzymatic hydrolysis of wood and the following fermentation of the products to ethanol. The substrate is a fiber fraction obtained by organosolv pre-treatment of beech wood. For the ethanol production, a co-fermentation by two different yeasts (Saccharomyces cerevisiae and Pachysolen tannophilus) was carried out to convert glucose as well as xylose. Two approaches has been followed: 1. A two step process, in which the hydrolysis of the fiber fraction and the fermentation to product are separated from each other. 2. A process, in which the hydrolysis and the fermentation are carried out in one single process step as simultaneous saccharification and fermentation (SSF). Following the first approach, a yield of about 0.15 g ethanol per gram substrate can be reached. Based on the SSF, one process step can be saved, and additionally, the gained yield can be raised up to 0.3 g ethanol per gram substrate.}, language = {en} } @inproceedings{AlKaidyUlberTippkoetter2014, author = {Al-Kaidy, H. and Ulber, Roland and Tippk{\"o}tter, Nils}, title = {A platform technology for the automated reaction control in magnetizable micro-fluidic droplets}, series = {Biomaterials - made in bioreactors : book of abstracts, May 26 - 28, 2014, Radisson Blu Park Hotel and Conference Dentre, Radebeul, Germany}, booktitle = {Biomaterials - made in bioreactors : book of abstracts, May 26 - 28, 2014, Radisson Blu Park Hotel and Conference Dentre, Radebeul, Germany}, publisher = {DECHEMA}, address = {Frankfurt am Main}, pages = {21 -- 22}, year = {2014}, language = {en} } @article{GerigkBujnickiGanpoNkwenkwaetal.2002, author = {Gerigk, M. and Bujnicki, R. and Ganpo-Nkwenkwa, E. and Bongaerts, Johannes and Sprenger, G. and Takors, Ralf}, title = {Process control for enhanced L-phenylalanine production using different recombinant Escherichia coli strains}, series = {Biotechnology and bioengineering}, volume = {Vol. 80}, journal = {Biotechnology and bioengineering}, number = {Iss. 7}, issn = {1097-0290 (E-Journal); 0006-3592 (Print)}, pages = {746 -- 754}, year = {2002}, language = {en} }