Xu S.,Northeast Forestry University |
Song Z.,CAF Institute of Chemical Industry of Forest Products |
Song Z.,Key and Open Laboratory on Forest Chemical Engineering |
Qian X.,Northeast Forestry University |
Shen J.,Northeast Forestry University
Cellulose | Year: 2013
For more cost-effective and/or value-added utilization of cellulosic fibers in pulp and paper industry, fiber engineering is an important concept. Essentially, fibers can be engineered via various mechanical, chemical, and biological processes. In the current study, the combined use of laccase and TEMPO was applied to introduce carboxyl and aldehyde groups to softwood-derived cellulosic fibers (bleached softwood kraft pulp). The process conditions in preparation of the engineered fibers were optimized. Under the conditions studied, the maximum increases in carboxyl and aldehyde contents were 360 % and 225 %, respectively. The effectiveness of the laccase/TEMPO system could be well explained by the reaction cycles in catalytic oxidation pathways. The findings of the current work may provide useful insights into the enzymatic modification of cellulosic fibers for papermaking applications. © 2013 Springer Science+Business Media Dordrecht.
Li W.,CAF Institute of Chemical Industry of Forest Products |
Li W.,Key and Open Laboratory on Forest Chemical Engineering |
Wang C.,CAF Institute of Chemical Industry of Forest Products |
Wang C.,Key and Open Laboratory on Forest Chemical Engineering |
Wang C.,Beijing Institute of Technology
BioResources | Year: 2015
Pyrogallol, as an important chemical raw material and reagent, has been prepared by the decarboxylation reaction of gallic acid hydrolyzing tannin acid extracted from Chinese gall, but the decarboxylation reaction is known to cause serious environmental pollution. To obtain efficient strains to degrade gallic acid, a screening study was carried out to explore different strains and optimal fermentation conditions of single impact factors, as well as using response surface methodology. The antioxidant bioactivity of products containing pyrogallol in the fermentation medium was also estimated. The results indicated that Enterobacter aerogenes could degrade gallic acid into pyrogallol with 77.86% average yield under the optimal fermentation conditions of an inoculum size of 5%, substrate concentration of 0.32%, incubation period of 60 h, fermentation temperature of 32 °C, content of phosphate buffer at 25%, and an initial pH of 6.0 in fermentation medium. The products contained 66.5% pyrogallol and were tested for their antioxidant capacity. They proved to have stronger antioxidant capacity compared with ABTS, BHT, and even Vc. In conclusion, the study provided a simple, highly efficient method, superior to complex genetic engineering technologies, to degrade gallic acid into pyrogallol, suggesting the possibility of large-scale production in the future.
Tao R.,CAF Institute of Chemical Industry of Forest Products |
Tao R.,National Engineering Laboratory for Biomass Chemical Utilization |
Tao R.,Key and Open Laboratory on Forest Chemical Engineering |
Tao R.,Key Laboratory of Biomass Energy and Material |
And 10 more authors.
Molecules | Year: 2013
Polyprenols separated from lipids are promising new components from Ginkgo biloba L. leaves (GBL). In this paper, ginkgo lipids were isolated by extraction with petroleum ether, saponification, and molecular distillation. Eight known compounds: isophytol (1), nerolidol (2), linalool (3), β-sitosterol acetate (4), β-sitosterol (5), stigmasterol (6), ergosterol (7), β-sitosterol-3-O-β-D-glucopyranoside (8) and Ginkgo biloba polyprenols (GBP) were separated from GBL by chromatography and identified mainly by NMR. The separated and identified compounds 1, 2 and 3 are reported here for the first time in GBL. The 3D-DAD-HPLC-chromatogram (190-232 nm) of GBP was recorded. This study provides new evidence as there are no previous reports on antibacterial/antifungal activities and synergistic interactions between GBP and the compounds separated from GBL lipids against Salmonella enterica, Staphylocococus aureus and Aspergillus niger. Nerolidol (2) showed the highest activity among all the tested samples and of all mixture groups tested the GBP with isophytol (1) mixture had the strongest synergistic effect against Salmonella enterica among the three tested strains. A proportion of isophytol and GBP of 38.19%:61.81% (wt/wt) was determined by mixture design as the optimal proportion for the synergistic effect of GBP with isophytol against Salmonella enterica. © 2013 by the authors.
Bian Y.,Key and Open Laboratory on Forest Chemical Engineering |
Liu S.,Key and Open Laboratory on Forest Chemical Engineering |
Jian X.,Key and Open Laboratory on Forest Chemical Engineering
Taiyangneng Xuebao/Acta Energiae Solaris Sinica | Year: 2015
The distillates of wood tar from 170 ℃ to 220 ℃ were obtained by the distillation method. 32 compounds in the distillates were identified by GC/MS and the weight of these compounds was over 97% of the weight of wood tar, meanwhile, total relative content of phenolic compounds was up to 79.57%. The synthesis of phenol-formaldehyde resin (PF) adhesive used wood tar to replace phenol partly, the orthogonal experiment of wood tar amount, reaction temperature and reaction time was carried out by NaOH catalysis method to confirm the best synthesis condition. The performance of produced PF adhesive satisfied the demands of GB/T 14732-2006 and the bonding strength reached 1.79 MPa. In the experimental conditions, the content of free phenol gradually decreased and content of free formaldehyde increased with the increase of content of wood tar. ©, 2015, Science Press. All right reserved.
Wu G.-M.,CAF Institute of Chemical Industry of Forest Products |
Wu G.-M.,National Engineering Laboratory for Biomass Chemical Utilization |
Wu G.-M.,Key and Open Laboratory on Forest Chemical Engineering |
Kong Z.-W.,CAF Institute of Chemical Industry of Forest Products |
And 8 more authors.
Journal of Applied Polymer Science | Year: 2011
A nonionic epoxy-based polyol (NTP) which can be used in place of the commonly used polyol dispersions to prepare two-component waterborne polyurethanes was synthesized with terpinene-maleic ester-type epoxy resin (TME), polyethylene glycol (PEG), and trimethylopropane (TMP) in the presence of sulfuric acid as catalyst. The synthesis process was tracked with gel permeation chromatography (GPC) and differential scanning calorimetry (DSC) by investigating the changes of molecular weight and glass transition temperature (Tg) of the product. FTIR was used to characterize the chemical structure of NTP. Major technical parameters of NTP were as follows: hydroxyl value 100 mg/g, hydroxyl group content 3.04%, Tg 4.03°C, and viscosity 150 mPa s (40% solid content). Effect of molecular weights and dosages of PEG on stability of NTP dispersion was examined by particle size analyses. It was found that stable dispersion was obtained when using PEG6000 as hydrophilic chain and its dosage ≤8% by the weight of TME. The average particle size of the prepared dispersion was about 200 nm from particles size and TEM analyses. The NTP dispersion showed characteristic of shear thinning, which indicated it was a pseudoplastic fluid. © 2010 Wiley Periodicals, Inc.