@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{WiesenTippkoetterMuffleretal.2014,
  author    = {Wiesen, Sebastian and Tippk{\"o}tter, Nils and Muffler, Kai and Suck, Kirstin and Sohling, Ulrich and Ruf, Nils and Ulber, Roland},
  title     = {Adsorptive Vorbehandlung von Rohglycerin f{\"u}r die 1,3-Propandiol Fermentation mit Clostridium diolis},
  series = {Chemie Ingenieur Technik},
  volume    = {86},
  journal   = {Chemie Ingenieur Technik},
  number    = {1-2},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  doi       = {10.1002/cite.201300080},
  pages     = {129 -- 135},
  year      = {2014},
  abstract  = {Bei der Gewinnung von Fetts{\"a}uren aus Pflanzen{\"o}len, z. B. zur Herstellung von Biopolymeren, oder bei der Biodiesel- und Seifenproduktion, f{\"a}llt Glycerin als Nebenprodukt an. Bei der Biokonversion dieses Rohstoffes zu 1,3-Propandiol wird der Produktionsorganismus Clostridium diolis durch Verunreinigungen im Rohglycerin gehemmt. Als inhibierende Substanzen konnten freie Fetts{\"a}uren identifiziert werden. Mithilfe eines adsorptiven Aufarbeitungsverfahrens ist es gelungen, die Fetts{\"a}uren zu entfernen und die Konversionseffizienz zu 1,3-Propandiol zu erh{\"o}hen.},
  language  = {de}
}
@article{WiesenTippkoetterMuffleretal.2015,
  author    = {Wiesen, Sebastian and Tippk{\"o}tter, Nils and Muffler, Kai and Suck, Kirstin and Sohling, Ulrich and Ruf, Friedrich and Ulber, Roland},
  title     = {Adsorption of fatty acids to layered double hydroxides in aqueous systems},
  series = {Adsorption},
  volume    = {21},
  journal   = {Adsorption},
  number    = {6-7},
  publisher = {Springer},
  address   = {Berlin},
  pages     = {459 -- 466},
  year      = {2015},
  abstract  = {Due to their anion exchange characteristics, layered double hydroxides (LDHs) are suitable for the detoxification of aqueous, fatty acid containing fermentation substrates. The aim of this study is to examine the adsorption mechanism, using crude glycerol from plant oil esterification as a model system. Changes in the intercalation structure in relation to the amount of fatty acids adsorbed are monitored by X-ray diffraction and infra-red spectroscopy. Additionally, calcination of LDH is investigated in order to increase the binding capacity for fatty acids. Our data propose that, at ambient temperature, fatty acids can be bound to the hydrotalcite by adsorption or in addition by intercalation, depending on fatty acid concentration. The adsorption of fatty acids from crude glycerol shows a BET-like behavior. Above a fatty acid concentration of 3.5 g L-1, intercalation of fatty acids can be shown by the appearance of an increased interlayer spacing. This observation suggests a two phase adsorption process. Calcination of LDHs allows increasing the binding capacity for fatty acids by more than six times, mainly by reduction of structural CO32-.},
  language  = {en}
}