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111.
Enhanced biotransformation of furfural and hydroxymethylfurfural by newly developed ethanologenic yeast strains 总被引:9,自引:0,他引:9
Z. Lewis Liu Patricia J. Slininger Steve W. Gorsich 《Applied biochemistry and biotechnology》2005,121(1-3):451-460
Furfural and hydroxymethylfurfural (HMF) are representative inhibitors among many inhibitive compounds derived from biomass
degradation and saccharification for bioethanol fermentation. Most yeasts, including industrial strains, are susceptible to
these inhibitory compounds, especially when multiple inhibitors are present. Additional detoxification steps add cost and
complexity to the process and generate additional waste products. To promote efficient bioethanol production, we studied the
mechanisms of stress tolerance, particularly to fermentation inhibitors such as furfural and HMF. We recently reported a metabolite
of 2,5-bis-hydroxymethylfuran as a conversion product of HMF and characterized a dose-dependent response of ethanologenic
yeasts to inhibitors. In this study, we present newly adapted strains that demonstrated higher levels of tolerance to furfural
and HMF. Saccharomyces cerevisiae 307-12H60 and 307-12H120 and Pichia stipitis 307 10H60 showed enhanced biotransformation ability to reduce HMF to 2,5-bis-hydroxymethylfuran at 30 and 60 mM, and S. cerevisiae 307-12-F40 converted furfural into furfuryl alcohol at significantly higher rates compared to the parental strains. Strains
of S. cerevisiae converted 100% of HMF at 60 mM and S. cerevisiae 307-12-F40 converted 100% of furfural into furfuryl alcohol at 30 mM. The results of this study suggest a possible in situ detoxification of the inhibitors by using more inhibitor-tolerant yeast strains for bioethanol fermentation. The development
of such tolerant strains provided a basis and useful materials for further studies on the mechanisms of stress tolerance. 相似文献
112.
Layered double hydroxides (LDHs) and their derivatives have been reported to be widely used as heterogeneous catalysts in various reactions. Herein, Ni‐Fe LDHs with the controlled Ni/Fe molar ratios (2:1, 3:1, 4:1) were synthesized via an easy hydrothermal method, which were used to catalyze the selective reduction of biomass‐derived furfural into furfuryl alcohol using 2‐propanol as a H‐donor under autogenous pressure and characterized using FT‐IR, XRD, TGA, BET, SEM, NH3‐TPD, and CO2‐TPD. It was found that the LDH with a Ni/Fe molar ratio of 3:1 demonstrated the best catalytic activity among the LDHs with different Ni/Fe molar ratios, which showed 97.0% conversion of furfural and 90.2% yield of furfuryl alcohol at 140°C for 5 hr. This was attributable to the synergistic effect of acidic sites and basic sites of the catalyst. 相似文献
113.
Ting Wang Hong Ma Xin Liu Yang Luo Shujing Zhang Yuxia Sun Xinhong Wang Jin Gao Jie Xu 《化学:亚洲杂志》2019,14(9):1515-1522
It is an attractive and challenging topic to endow non‐noble metal catalysts with high efficiency via a nitrogen‐doping approach. In this study, a nitrogen‐doped carbon catalyst with high nitrogen content encapsulating cobalt NPs (CoOx@N‐C(g)) was synthesized, and characterized in detail by XRD, HRTEM, N2‐physisorption, ICP, CO2‐TPD, and XPS techniques. g‐C3N4 nanosheets act as nitrogen source and self‐sacrificing templates, giving rise to an ultrahigh nitrogen content of 14.0 %, much higher than those using bulk g‐C3N4 (4.4 %) via the same synthesis procedures. As a result, CoOx@N‐C(g) exhibited the highest performance in the oxidative esterification of biomass‐derived platform furfural to methylfuroate under base‐free conditions, achieving 95.0 % conversion and 97.1 % selectivity toward methylfuroate under 0.5 MPa O2 at 100 °C for 6 h, far exceeding those of other cobalt‐based catalysts. The high efficiency of CoOx@N‐C(g) was closely related to its high ratio of pyridinic nitrogen species that may act as Lewis basic sites as well as its capacity for the activation of dioxygen to superoxide radical O2.?. 相似文献
114.
6-Arylidene-2-furfurylidenecyclohexanones were obtained by the condensation of cyclohexanone with aldehydes of the aromatic and furan series under conditions of base or acid catalysis. The effect of substituents in the aromatic ring on the activity of the initial aldehyde was studied. According to data from the IR spectra, the obtained ketones exist in the form of trans,trans isomers.__________Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 191–195, February, 2005. 相似文献
115.
5-(α-D-Glucosyloxymethyl)furfural, a versatile building block from renewable resources, was prepared from isomaltulose–choline chloride melts by acid catalysis. In this solvent-free process, moderate yields were achieved under mild reaction conditions. 相似文献
116.
Alexander Kaszonyi Lívia Izsk Milan Krlik Michal Jablonsky 《Molecules (Basel, Switzerland)》2022,27(9)
Samples of papers artificially (2 to 60 days) and naturally (10, 45, and 56 years) aged were studied by the Py-GC/MS method to identify decomposition products. Possible reaction scenarios for cellulose degradation were developed. One of the degradation products is acetic acid, which can (auto)catalyze the cleavage of cellulose β(1→4)-glycosidic bonds of cellulose polymer chains. However, during 20 s of Py-GC/MS analysis, temperatures of up to 300 °C did not significantly increase or modify the formation of decomposition products of paper components. At 300 °C, the amount of several cellulose decomposition products increased regularly depending on the number of days of artificial aging and natural aging, demonstrated mainly by the generation of 2-furancarboxaldehyde, 5-hydroxymethylfurfural, and levoglucosan and its consecutive dehydration products. No correlation between the amount of lignin decomposition products and the time of aging was found when the pyrolysis was performed at 300 °C and 500 °C. Compounds present in the products of decomposition at 500 °C bear the imprint of the chemical composition of the sampled paper. Pyrograms taken at 300 °C using the Py-GC/MS method can give additional information on the changes in the chemical structure of paper during natural or artificial aging, mainly about the cleavage of β(1→4)-glycosidic bonds during aging. 相似文献
117.
Christoph Derflinger Prof. Dr. Birgit Kamm Georg Leitner Prof. Dr. Christian Paulik 《European journal of organic chemistry》2023,26(23):e202300311
In this work, resol based binders were prepared with lignin, resorcinol and the bio-based aldehydic platform chemicals 5-hydroxymethylfurfural (HMF) and 2,5-diformylfuran (DFF). In preliminary studies, the solubility and stability of DFF in aqueous-alkaline conditions was investigated. Various binders were prepared to investigate the influence of the HMF-DFF ratio and the influence of the aldehyde concentration on the molar mass, rheological properties and curing characteristics of the final binders. It is shown that significantly higher molecular weights and viscosities are obtained by using DFF instead of HMF. The properties of the final binder could also be affected by the precise choice of DFF concentration, as this resulted in higher levels of crosslinking. This work offers a novel type of fully bio-based binder that consists of non-toxic components and is therefore less hazardous than some conventional binders. 相似文献