Epoxidation and etherification of alkaline lignin to prepare water-soluble derivatives and its performance in improvement of enzymatic hydrolysis efficiency

Abstract

BackgroundDue to the depletion of fossil resources and their environmental impact, woody biomass has received much attention as an alternative resource. Lignin, as the third most abundant biopolymer from biomass, is now considered as an excellent alternative feedstock for chemicals and materials. The conversion of lignin to the value-added products is a key process to achieve an integrated biorefinery of woody biomass. Among these value-added products, lignin-based derivatives with good surface activity can be applied to enhance the conversion of cellulose into fermentable sugars, which not only decrease the cost of bioethanol production, but also reduce the environmental pollution and green house effect resulting from the burning of fossil resources.ResultsWater-soluble alkaline lignin was synthesized by the reaction between polyethylene glycols (PEG600 and PEG1000) and epoxy lignin. FT-IR and NMR analyses indicated that PEGs were successively introduced into epoxy alkaline lignin using potassium persulfate as a catalyst. Emulsification and surface activity tests indicated that the surface tension of the prepared lignin derivative solution was 43.30 mN/m at the critical micelle concentration (1.03 %). A stable emulsions layer was formed with hexanes and the emulsion particle diameter in the emulsion phase for all products was observed at 10–50 μm. The results of enzymatic hydrolysis indicated that the products derived from PEG1000-grafted lignin resulted in the highest increasing rate of 18.6 % of glucose yield during the enzymatic hydrolysis of hardwood bleached pulp. The results of fermentation experiments suggested that the product had no toxicity for fermentation micro-organisms.ConclusionWater-soluble alkaline lignin derivatives were prepared through epoxidation and etherification, which are promising feedstocks for detergents, emulsifier, and additive to enhance enzymatic hydrolysis efficiency and ethanol fermentation.Electronic supplementary materialThe online version of this article (doi:10.1186/s13068-016-0499-9) contains supplementary material, which is available to authorized users.

A Solvent‐Resistant and Biocompatible Self‐Healing Supramolecular Elastomer with Tunable Mechanical Properties

“…In the first step, DETA‐terminated amide chains were branched on the lignin by reacting sebacic acid and lignin with DETA. The fourier transform infrared (FTIR) and X‐ray photoelectron spectroscopy (XPS) spectra of lignin in Figures S1 and S2 in the Supporting Information exhibit that lignin has carboxyl and hydroxyl groups, which agrees with previous report . The carboxyl groups of lignin can react with amine groups of DETA to form amide, which has been confirmed by XPS spectra in Figure S2 in the Supporting Information.…”

Choosing the Right Lignin to Fully Replace Bisphenol A in Epoxy Resin Formulation

“…Lignin can be incorporated into epoxy resin via three different methods: 1) blending with petroleum‐based epoxy resin, [24,25] 2) modification of lignin followed by epoxidation, [23,26–30] and 3) epoxidation of unmodified lignin [16,31,32] . Although many studies have focused on utilizing lignin in epoxy resin, [23,27,33,34] they mostly used modified lignin (fractionated or lignin monomers) [23,27,29] . For instance, several studies used small compounds obtained from lignin, including syringaresinol, [35] isosorbide diferulate, [36,37] bisguaiacol, [22] diphenolic acid, [38] and ferulic acid [39–41] to synthesize epoxy resins.…”

Lignin as an Active Biomaterial: A Review

“…High-temperature sulfonation, sulfomethylation, oxidation sulfonation, oxidation nitration (Huang et al 2018;Konduri and Fatehi, 2018) Amphoteric surfactant Amination of lignosulfonate (Cai et al 2017;Lou et al 2019;Tian et al 2014) Nonionic surfactant Hydroxyl ammonium reaction, etherification, epoxidation (Chen et al 2016;Huang et al 2019) Fig. 3.…”

“…It was applied in the enzymatic hydrolysis of hardwood bleached pulp, and the result showed an increased glucose yield rate of as much as 18%. Moreover, observation of the fermentation experiment showed that the product was not toxic for fermentation yeast (Chen et al 2016). Cai et al (2017) synthesized lignin amphoteric surfactant (SLQA) by reacting lignin lignosulfonate with (3-Chloro-2-hydroxypropyl)trimethylammonium Chloride (CHPTAC).…”