Browsing by Author "Fockink, Douglas, H."
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- Contribution to the production and use of biomass-derived solvents : a reviewPublication . Kochepka, Débora Merediane; Dill, Laís Pastre; Fockink, Douglas, H.; Lukasik, Rafal M.ABSTRACT: In this review key processes for the synthesis of greener or more sustainable solvents derived from renewable sources (saccharides, lignocellulose and triglycerides) are discussed. It is shown that a series of platform chemicals such as glycerol, levulinic acid and furans can be converted into a variety of solvents through catalytic transformations that include hydrolysis, esterification, reduction and etherification reactions. It was also considered several aspects of each class of solvent regarding performance within the context of the reactions or extractions for which it is employed.
- Insight into the high-pressure CO2 pre-treatment of sugarcane bagasse for a delivery of upgradable sugarsPublication . Fockink, Douglas, H.; Morais, Ana Rita C.; Ramos, Luiz Pereira; Lukasik, Rafal M.ABSTRACT: This work provides an insight into sugarcane bagasse pre-treatment carried out with greener and more sustainable CO2/H2O system. Temperatures and residence times at a fixed initial CO2 pressure were studied to verify their effects on pre-treatment efficiency with regard to the chemical composition of both water-soluble and water-insoluble fractions as well as to the susceptibility of the latter to enzymatic hydrolysis at high total solids. Also, trends in enzymatic hydrolysis were analysed in function of biomass crystallinity. This work provides an integrated approach in the analysis of upgradable sugars that are released as a result of pre-treatment and enzymatic hydrolysis. At optimal pre-treatment conditions, 17.2 g.L-1 sugars were released in the water-soluble fraction mainly as pentoses in monomeric and oligomeric forms. The enzymatic hydrolysis of solids produced at these pre-treatment conditions gave 76.8 g.L-1 glucose in the substrate hydrolysate. The overall sugar yield delivered in both pre-treatment and enzymatic hydrolysis was 73,9 mol%. These results were compared to the chemical effect of hydrothermal and/or physico-chemical effects of N-2-aided hydrothermal processes and showed that the greener processing of biomass pre-treatment with CO2 is advantageous for the integrated valorisation of industrial residues and delivery of upgradable sugars within the biorefinery concept.
- Pretreatment of cotton spinning residues for optimal enzymatic hydrolysis: a case study using green solventsPublication . Fockink, Douglas, H.; Andreaus, Jurgen; Ramos, Luiz Pereira; Lukasik, Rafal M.ABSTRACT: The effectiveness of imidazole and ionic liquid pretreatments for the conversion of cotton spinning residues (dirty cotton residue - DCR and cotton filter powder - CFP) into soluble sugars was investigated. DCR was pretreated with imidazole using temperatures and reaction times that were arranged in a 2(2) factorial design and pretreatment performance was evaluated by enzymatic hydrolysis. High glucan to glucose and xylan to xylose yields (78.0 and 94.9 mol %) were obtained from the solids produced at 140 degrees C and 2h (center point), which provided delignification levels of 45.5% (w.v(-1)). The same pretreatment condition was applied to CFP yielding only 16.0% (w.v(-1)) of delignification, but 75.8 mol % of glucan and 95.7 mol % of xylan were converted as their corresponding monomeric sugars after enzymatic hydrolysis. Both pretreated materials were subjected to a central composite design to find the best enzymatic hydrolysis conditions regarding substrate total solids (TS) and enzyme loading. More than 40 g.L-1 glucose was obtained from both pretreated materials at 13.7% w.w(-1) TS and 20 FPU.g(-1) glucan after 96 h of hydrolysis. Ionic liquid pretreatment of the same cotton spinning residues showed moderate delignification levels, accompanied by a change in biomass crystallinity from cellulose 1 beta to cellulose II. This turned to be very important to improve enzymatic hydrolysis yields. Therefore, biomass delignification and crystallinity confirmed to be key factors governing the enzymatic saccharification of cotton spinning residues.
- The green biorefinery concept for the valorisation of pistachio shell by high-pressure CO2/H2O systemPublication . Özbek, Hatice Neval; Fockink, Douglas, H.; Yanik, Derya Koçak; Gögüs, Fahrettin; Lukasik, Rafal M.ABSTRACT: The use of high-pressure CO2/H2O in valorisation of pistachio shell to produce hemicellulose-derived, oligomeric and monomeric sugars and their further transformation to furfural as well as enzymatic transformation of cellulose-rich solids is presented in this work. Different pre-treatment conditions i.e. temperature ranged from 160 to 200 degrees C; reaction time varied between 0 and 30 min and liquid to solid mass ratio between 4 and 8 with constant initial pressure of CO2 of 50 bars were examined. At the optimal pre-treatment conditions, the concentrations of xylose and xylo-oligosaccharide were of 1.7 and 35.5 g/L. Furthermore, this work demonstrates the high-pressure CO2 catalysed production of furfural in an aqueous/tetrahydrofuran system. For model solution containing a mixture of xylose and acetic acid, the optimised furfural yield was as high as 53.3 mol%, while for real sample of hemicellulose hydrolysate, the furfural yield of 39.6 mol% and the selectivity of 40.0 mol% were obtained. Additionally, quantitative glucan to glucose conversion by enzymatic hydrolysis of pre-treated cellulose-rich biomasses was achieved.