Ludwig Daniel, Michael Buchmann, Hirth Thomas, Rupp Steffen, Zibek Susanne
Evonik Industries AG, Rodenbacher Chaussee 4, 63457, Hanau-Wolfgang, Germany.
Appl Biochem Biotechnol. 2014 Feb;172(3):1699-713. doi: 10.1007/s12010-013-0607-2. Epub 2013 Nov 19.
In this study, we present a powerful stirred tank reactor system that can efficiently hydrolyse lignocellulosic material at high solid content to produce hydrolysates with glucose concentration > 100 g/kg. As lignocellulosic substrates alkaline-pretreated wheat straw and organosolv-pretreated beech wood were used. The developed vertical reactor was equipped with a segmented helical stirrer, which was specially designed for high biomass hydrolysis. The stirrer was characterised according to mixing behaviour and power input. To minimise the cellulase dosage, a response surface plan was used. With the empirical relationship between glucose yield, cellulase loading and solid content, the minimal cellulase dosage was calculated to reach at least 70% yield at high glucose and high substrate concentrations within 48 h. The optimisation resulted in a minimal enzyme dosage of 30 FPU/g dry matter (DM) for the hydrolysis of wheat straw and 20 FPU/g DM for the hydrolysis of beech wood. By transferring the hydrolysis reaction from shaking flasks to the stirred tank reactor, the glucose yields could be increased. Using the developed stirred tank reactor system, alkaline-pretreated wheat straw could be converted to 110 g/kg glucose (76%) at a solid content of 20% (w/w) after 48 h. Organosolv-pretreated beech wood could be efficiently hydrolysed even at 30% (w/w) DM, giving 150 g/kg glucose (72%).
在本研究中，我们展示了一种强大的搅拌罐反应器系统，该系统能够在高固含量下高效水解木质纤维素材料，以生产葡萄糖浓度>100 g/kg的水解产物。使用了碱预处理小麦秸秆和有机溶剂预处理山毛榉木作为木质纤维素底物。所开发的立式反应器配备了分段螺旋搅拌器，该搅拌器是专门为高生物质水解设计的。根据混合行为和功率输入对搅拌器进行了表征。为了使纤维素酶用量最小化，采用了响应面设计。利用葡萄糖产率、纤维素酶负载量和固含量之间的经验关系，计算出在48小时内，在高葡萄糖和高底物浓度下达到至少70%产率所需的最小纤维素酶用量。优化后，小麦秸秆水解的最小酶用量为30 FPU/g干物质（DM），山毛榉木水解的最小酶用量为20 FPU/g DM。通过将水解反应从小摇瓶转移到搅拌罐反应器中，可以提高葡萄糖产率。使用所开发的搅拌罐反应器系统，碱预处理小麦秸秆在48小时后，在20%（w/w）的固含量下可转化为110 g/kg葡萄糖（76%）。有机溶剂预处理的山毛榉木即使在30%（w/w）DM的情况下也能有效水解，得到150 g/kg葡萄糖（72%）。
