Department of Process Engineering and Chemical Technology, Faculty of Chemistry, Gdansk University of Technology, G. Narutowicza St. 11/12, 80-233 Gdańsk, Poland.
EcoTech Center, Research Centre, Gdańsk University of Technology, G. Narutowicza St. 11/12, 80-233 Gdańsk, Poland.
Molecules. 2021 Dec 28;27(1):157. doi: 10.3390/molecules27010157.
The methods for hydrogen yield efficiency improvements, the gaseous stream purification in gaseous biofuels generation, and the biomass pretreatment are considered as the main trends in research devoted to gaseous biofuel production. The environmental aspect related to the liquid stream purification arises. Moreover, the management of post-fermentation broth with the application of various biorefining techniques gains importance. Chemical compounds occurring in the exhausted liquid phase after biomass pretreatment and subsequent dark and photo fermentation processes are considered as value-added by products. The most valuable are furfural (FF), 5-hydroxymethylfurfural (HMF), and levulinic acid (LA). Enriching their solutions can be carried with the application of liquid-liquid extraction with the use of a suitable solvent. In these studies, hydrophobic deep eutectic solvents (DESs) were tested as extractants. The screening of 56 DESs was carried out using the Conductor-like Screening Model for Real Solvents (COSMO-RS). DESs which exposed the highest inhibitory effect on fermentation and negligible water solubility were prepared. The LA, FF, and HMF were analyzed using FT-IR and NMR spectroscopy. In addition, the basic physicochemical properties of DES were carefully studied. In the second part of the paper, deep eutectic solvents were used for the extraction of FF, LA, and HMF from post-fermentation broth (PFB). The main extraction parameters, i.e., temperature, pH, and DES: PFB volume ratio (V:V), were optimized by means of a Box-Behnken design model. Two approaches have been proposed for extraction process. In the first approach, DES was used as a solvent. In the second, one of the DES components was added to the sample, and DES was generated in situ. To enhance the post-fermentation broth management, optimization of the parameters promoting HMF, FF, and LA extraction was carried under real conditions. Moreover, the antimicrobial effect of the extraction of FF, HMF, and LA was investigated to define the possibility of simultaneous separation of microbial parts and denatured peptides via precipitation.
提高产氢效率的方法、气态生物燃料生成中气态流的净化以及生物质的预处理被认为是气态生物燃料生产研究的主要趋势。与液态流净化相关的环境问题出现了。此外，应用各种生物炼制技术对发酵后醪液的管理变得越来越重要。在生物质预处理以及随后的暗发酵和光发酵过程之后，在耗尽的液相中出现的化学化合物被认为是增值的副产品。最有价值的是糠醛（FF）、5-羟甲基糠醛（HMF）和乙酰丙酸（LA）。可以通过使用合适的溶剂进行液-液萃取来富集它们的溶液。在这些研究中，疏水性深共晶溶剂（DES）被用作萃取剂。使用用于真实溶剂的导带电浆模型（COSMO-RS）对 56 种 DES 进行了筛选。制备了对发酵表现出最高抑制作用和可忽略的水溶解度的 DES。使用傅里叶变换红外光谱（FT-IR）和核磁共振光谱（NMR）对 LA、FF 和 HMF 进行了分析。此外，还仔细研究了 DES 的基本物理化学性质。在本文的第二部分，深共晶溶剂用于从发酵后醪液（PFB）中萃取 FF、LA 和 HMF。通过 Box-Behnken 设计模型优化了主要的萃取参数，即温度、pH 和 DES：PFB 体积比（V:V）。提出了两种萃取方法。第一种方法是使用 DES 作为溶剂。第二种方法是向样品中添加 DES 的一种成分，然后就地生成 DES。为了加强发酵后醪液的管理，在实际条件下对促进 HMF、FF 和 LA 萃取的参数进行了优化。此外，还研究了萃取 FF、HMF 和 LA 的抗菌效果，以确定通过沉淀同时分离微生物部分和变性肽的可能性。
