Conversion of organosolv pretreated hardwood biomass into 5-hydroxymethylfurfural (HMF) by combining enzymatic hydrolysis and isomerization with homogeneous catalysis

Abstract

Background Over the last few years, valorization of lignocellulosic biomass has been expanded beyond the production of second-generation biofuels to the synthesis of numerous platform chemicals to be used instead of their fossil-based counterparts. One such well-researched example is 5-hydroxymethylfurfural (HMF), which is preferably produced by the dehydration of fructose. Fructose is obtained by the isomerization of glucose, which in turn is derived by the hydrolysis of cellulose. However, to avoid harsh reaction conditions with high environmental impact, an isomerization step towards fructose is necessary, as fructose can be directly dehydrated to HMF under mild conditions. This work presents an optimized process to produce fructose from beechwood biomass hydrolysate and subsequently convert it to HMF by employing homogeneous catalysis. Results The optimal saccharification conditions were identified at 10% wt. solids loading and 15 mg enzyme/gsolids, as determined from preliminary trials on pure cellulose (Avicel® PH-101). Furthermore, since high rate glucose isomerization to fructose requires the addition of sodium tetraborate, the optimum borate to glucose molar ratio was determined to 0.28 and was used in all experiments. Among 20 beechwood solid pulps obtained from different organosolv pretreatment conditions tested, the highest fructose production was obtained with acetone (160 °C, 120 min), reaching 56.8 g/100 g pretreated biomass. A scale-up hydrolysis in high solids (25% wt.) was then conducted. The hydrolysate was subjected to isomerization eventually leading to a high-fructose solution (104.5 g/L). Dehydration of fructose to HMF was tested with 5 different catalysts (HCl, H3PO4, formic acid, maleic acid and H-mordenite). Formic acid was found to be the best one displaying 79.9% sugars conversion with an HMF yield and selectivity of 44.6% and 55.8%, respectively. Conclusions Overall, this work shows the feasibility of coupling bio- and chemo-catalytic processes to produce HMF from lignocellulose in an environmentally friendly manner. Further work for the deployment of biocatalysts for the oxidation of HMF to its derivatives could pave the way for the emergence of an integrated process to effectively produce biobased monomers from lignocellulose.

Roles of Ball Milling Pretreatment and Titanyl Sulfate in the Synthesis of 5-Hydroxymethylfurfural from Cellulose

“…The selective oxidation of HMF delivers 2,5-furandicarboxylic acid (FDCA), a well-documented monomer to displace petroleum-based terephthalic acid to manufacture high-performance biorenewable polymers . Owing to the importance of HMF as multipurpose platform toward high-value products, varied catalytic systems have been studied for the transformation of biomass and its constituent C 6 sugars to HMF. , Obtaining HMF from lignocellulosic biomass necessitates a battery of complicated steps, including pretreatment, saccharification, isomerization, and dehydration. , …”

“…4,9 Obtaining HMF from lignocellulosic biomass necessitates a battery of complicated steps, including pretreatment, saccharification, isomerization, and dehydration. 10,11 The dehydration of fructose, the most facile starting material, to HMF has been investigated extensively for a long time. Although both high yield and selectivity could be acquired from fructose, most catalytic systems depend heavily on the use of certain high boiling point solvents, in particular, dimethyl sulfoxide (DMSO) and ionic liquid.…”

Highly efficient fermentation of 5-keto-d-fructose with Gluconobacter oxydans at different scales

“…A decomposition intermediate of hexoses is 5-hydroxymethylfurfural (HMF) [ 78 ], mainly at pH values below 7 [ 82 ]. HMF is also a by-product of lignocellulosic pre-treatment and a well-known inhibitor of microorganisms [ 51 , 52 , 83 – 86 ]. Using biomass hydrolysates as substrates for the cultivation of G. oxydans showed inhibitory effects, e.g.…”

Integrated chemo‐ and biocatalytic processes: a new fashion toward renewable chemicals production from lignocellulosic biomass

“…One typical one-pot process for this integrated catalytic reaction is to first isomerize glucose into fructose using GIase, followed by fructose dehydration into HMF using chemical catalysts. Dedes et al 27 used organosolv-pretreated beechwood as feedstock and converted the cellulose into fructose via sequential cellulase and GIase treatment. Then, formic acid was added to catalyze the transformation of fructose into HMF, and HMF yield and selectivity of 44.6% and 55.8%, respectively, were achieved.…”

“…One typical one‐pot process for this integrated catalytic reaction is to first isomerize glucose into fructose using GIase, followed by fructose dehydration into HMF using chemical catalysts. Dedes et al 27 . used organosolv‐pretreated beechwood as feedstock and converted the cellulose into fructose via sequential cellulase and GIase treatment.…”