TY  - CHAP
A1  - Muffler, Kai
A1  - Poth, Sabastian
A1  - Sieker, Tim
A1  - Tippkötter, Nils
A1  - Ulber, Roland
A1  - Sell, Dieter
ED  - Moo-Young, Murray
T1  - Bio-feedstocks
T2  - Comprehensive biotechnology : principles and practices in industry, agcriculture, medicine and the environment. Volume 2: Engineering fundamentals of biotechnology
Y1  - 2011
SN  - 978-0-444-53352-4
U6  - http://dx.doi.org/10.1016/B978-0-08-088504-9.00088-X
SP  - 93
EP  - 101
PB  - Elsevier
CY  - Amsterdam
ET  - 2. edition
ER  - 
TY  - JOUR
A1  - Sieker, Tim
A1  - Neuner, Andreas
A1  - Dimitrova, Darina
A1  - Tippkötter, Nils
A1  - Muffler, Kai
A1  - Bart, Hans-Jörg
A1  - Heinzle, Elmar
A1  - Ulber, Roland
T1  - Ethanol production from grass silage by simultaneous pretreatment, saccharification and fermentation: First steps in the process development
JF  - Engineering in Life Sciences
N2  - Grass silage provides a great potential as renewable feedstock. Two fractions of the grass silage, a press juice and the fiber fraction, were evaluated for their possible use for bioethanol production. Direct production of ethanol from press juice is not possible due to high concentrations of organic acids. For the fiber fraction, alkaline peroxide or enzymatic pretreatment was used, which removes the phenolic acids in the cell wall. In this study, we demonstrate the possibility to integrate the enzymatic pretreatment with a simultaneous saccharification and fermentation to achieve ethanol production from grass silage in a one-process step. Achieved yields were about 53 g ethanol per kg silage with the alkaline peroxide pretreatment and 91 g/kg with the enzymatic pretreatment at concentrations of 8.5 and 14.6 g/L, respectively. Furthermore, it was shown that additional supplementation of the fermentation medium with vitamins, trace elements and nutrient salts is not necessary when the press juice is directly used in the fermentation step.
Y1  - 2011
U6  - http://dx.doi.org/10.1002/elsc.201000160
N1  - Special Issue "Bioprocess‐oriented plant design"
VL  - 11
IS  - 4
SP  - 436
EP  - 442
PB  - Wiley
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Tippkötter, Nils
A1  - Duwe, Anna-Maria
A1  - Wiesen, Sebastian
A1  - Sieker, Tim
A1  - Ulber, Roland
T1  - Enzymatic hydrolysis of beech wood lignocellulose at high solid contents and its utilization as substrate for the production of biobutanol and dicarboxylic acids
JF  - Bioresource Technology
N2  - 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.
Y1  - 2014
U6  - http://dx.doi.org/10.1016/j.biortech.2014.06.052
VL  - 167
SP  - 447
EP  - 455
PB  - Elsevier
CY  - Amsterdam
ER  -