VTI Institute for Wood Technology and Wood Biology

Hamburg, Germany

VTI Institute for Wood Technology and Wood Biology

Hamburg, Germany
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Rocha G.J.M.,CTBE - Brazilian Bioethanol Science and Technology Laboratory | Silva V.F.N.,CTBE - Brazilian Bioethanol Science and Technology Laboratory | Silva V.F.N.,University of Sao Paulo | Martin C.,University of Matanzas | And 4 more authors.
Sugar Tech | Year: 2013

This work was aimed to evaluate the effect of the removal of hemicellulose and lignin, by hydrothermal pretreatment, carried out at four different temperatures, namely 180, 185, 190 and 195 °C, for 10 min in a 20-L reactor, and alkaline delignification with 1.0 % (w/v) NaOH, at 100 °C for 1 h, on the enzymatic saccharification of sugarcane bagasse cellulose. For the material pretreated under the most severe conditions (1.0 % (w/v) NaOH, 100 °C, 1 h and 195 °C, 10 min), 95.8 % of the hemicellulosic fraction and 80.9 % of lignin were solubilised upon pretreatment and delignification respectively. The enzymatic conversion of the material obtained under those conditions reached 89.2 % of the initial cellulose, whereas it was 69.2 % for the pretreated but non-delignified material and only 6.0 % for raw bagasse. Models describing the effect of hemicellulose and lignin content on the enzymatic hydrolysis were developed. The statistical analysis of the results emphasized the significance of removal of the hemicellulose and lignin for improving the enzymatic hydrolysis of cellulose. © 2013 Society for Sugar Research & Promotion.


Martin C.,University of Matanzas | Martin C.,VTI Institute for Wood Technology and Wood Biology | De Moraes Rocha G.J.,CTBE - Brazilian Bioethanol Science and Technology Laboratory | Dos Santos J.R.A.,Federal University of Pernambuco | And 2 more authors.
Quimica Nova | Year: 2012

The enzymatic hydrolysis of steam-pretreated sugarcane bagasse, either delignified or non-delignified, was studied as a function of enzyme loading. Hydrolysis experiments were carried out using five enzyme loadings (2.5 to 20 FPU/g cellulose) and the concentration of solids was 2% for both materials. Alkaline delignification improved cellulose hydrolysis by increasing surface area. For both materials, glucose concentrations increased with enzyme loading. On the other hand, enzyme loadings higher than 15 FPU/g did not result in any increase in the initial rate, since the excess of enzyme adsorbed onto the substrate restricted the diffusion process through the structure.


Wanderley M.C.D.A.,Federal University of Pernambuco | Martin C.,University of Matanzas | Martin C.,VTI Institute for Wood Technology and Wood Biology | Rocha G.J.D.M.,CTBE - Brazilian Bioethanol Science and Technology Laboratory | Gouveia E.R.,Federal University of Pernambuco
Bioresource Technology | Year: 2013

Enzymatic hydrolysis of pretreated sugarcane bagasse was performed to investigate the production of ethanol. The sugarcane bagasse was pretreated in a process combining steam explosion and alkaline delignification. The lignin content decreased to 83%. Fed-batch enzymatic hydrolyses was initiated with 8% (w/v) solids loading, and 10. FPU/g cellulose. Then, 1% solids were fed at 12, 24 or 48. h intervals. After 120. h, the hydrolysates were fermented with Saccharomyces cerevisiae UFPEDA 1238, and a fourfold increase in ethanol production was reached when fed-batch hydrolysis with a 12-h addition period was used for the steam pretreated and delignified bagasse. © 2012 Elsevier Ltd.


Oliveira F.M.V.,University of Sao Paulo | Pinheiro I.O.,University of Pernambuco | Souto-Maior A.M.,Federal University of Pernambuco | Martin C.,University of Matanzas | And 3 more authors.
Bioresource Technology | Year: 2013

Steam explosion at 180, 190 and 200°C for 15min was applied to sugarcane straw in an industrial sugar/ethanol reactor (2.5m3). The pretreated straw was delignificated by sodium hydroxide and hydrolyzed with cellulases, or submitted directly to enzymatic hydrolysis after the pretreatment. The pretreatments led to remarkable hemicellulose solubilization, with the maximum (92.7%) for pretreatment performed at 200°C. Alkaline treatment of the pretreated materials led to lignin solubilization of 86.7% at 180°C, and only to 81.3% in the material pretreated at 200°C. All pretreatment conditions led to high hydrolysis conversion of cellulose, with the maximum (80.0%) achieved at 200°C. Delignification increase the enzymatic conversion (from 58.8% in the cellulignin to 85.1% in the delignificated pulp) of the material pretreated at 180°C, but for the material pretreated at 190°C, the improvement was less remarkable, while for the pretreated at 200°C the hydrolysis conversion decreased after the alkaline treatment. © 2012 Elsevier Ltd.


Rocha G.J.M.,CTBE - Brazilian Bioethanol Science and Technology Laboratory | Martin C.,University of Matanzas | Martin C.,VTI Institute for Wood Technology and Wood Biology | da Silva V.F.N.,University of Sao Paulo | And 2 more authors.
Bioresource Technology | Year: 2012

Five pilot-scale steam explosion pretreatments of sugarcane bagasse followed by alkaline delignification were explored. The solubilised lignin was precipitated with 98% sulphuric acid. Most of the pentosan (82.6%), and the acetyl group fractions were solubilised during pretreatment, while 90.2% of cellulose and 87.0% lignin were recovered in the solid fraction. Approximately 91% of the lignin and 72.5% of the pentosans contained in the steam-exploded solids were solubilised by delignification, resulting in a pulp with almost 90% of cellulose. The acidification of the black liquors allowed recovery of 48.3% of the lignin contained in the raw material. Around 14% of lignin, 22% of cellulose and 26% of pentosans were lost during the process. In order to increase material recovery, major changes, such as introduction of efficient condensers and the reduction in the number of washing steps, should be done in the process setup. © 2012 Elsevier Ltd.


Martin C.,VTI Institute for Wood Technology and Wood Biology | Martin C.,University of Matanzas | Puls J.,VTI Institute for Wood Technology and Wood Biology | Schreiber A.,Sudan University of Science and Technology | Saake B.,Sudan University of Science and Technology
Holzforschung | Year: 2013

A combined pretreatment of sugarcane bagasse with glycerol and sulfuric acid was investigated based on a central composite rotatable experimental design. The following factors were varied: temperature (150-199 C), time (0.69-2.3 h), H2SO4 concentration (0.0-1.1%), and glycerol concentration (55.4-79.6%). Xylans and lignin were considerably solubilized during pretreatment. Xylan solubilization, ranging between 6% and 94%, increased significantly with the increase of temperature, time, and H2SO 4 concentration and dropped with the increase of glycerol amount. Glycerol restricted the solubilization and full hydrolysis of xylans and the degradation of xylose. Lignin solubilization (20.6-49.4%) increased with the increase of all the experimental factors. Cellulose recovery, which was generally high, increased with the increasing of glycerol concentration and declined at high levels of the other factors. Recoveries above 97% were achieved at low H2SO4 concentration and high glycerol load, whereas the lowest value (83.4%) was achieved in the longest-lasting experiment. The models based on the experimental results predicted the maximal lignin solubilization at 187.7 C, 2.3 h, 79.6% glycerol, and 0.64% H2SO 4, whereas the highest yield of enzymatic hydrolysis can be expected at 194.1 C, 1.67 h, 79.6% glycerol, and 1.1% H2SO4. The optimal conditions were confirmed in control experiments. The synergistic effect of sulfuric acid and glycerol on the enzymatic hydrolysis of cellulose was demonstrated. © 2013 by Walter de Gruyter Berlin Boston 2013.


Wendler F.,Thurlnglan Institute for Textile and Plastics Research | Meister F.,Thurlnglan Institute for Textile and Plastics Research | Wawro D.,Institute of Biopolymers and Chemical Fibres | Wesolowska E.,Institute of Biopolymers and Chemical Fibres | And 5 more authors.
Fibres and Textiles in Eastern Europe | Year: 2010

The aim of the study was to find new structured biopolymer blends bearing adjustable properties able to produce innovative materials. Apart from cellulose and three solvents (NaOH, N-methylmorpholine-N-oxide [NMMO] and 1-ethyl-3-methylimidazolium acetate [EMIMac]), 15 different polysaccharides were chosen to study the interactions ofpolysaccharides or their mixtures in solutions, as well as the solid state after forming. Dissolution screenings yielded promising polysaccharides, which were used for the preparation of cellulose/ polysaccharide solutions and subsequently for the shaping of blends with cellulose. The solubility and miscibility were evaluated by microscopy, DSC, particle analysis and rheology. Polysaccharides with a structure similar to that of cellulose, e.g., xylan, carrageenan or cellulose carbamate were not miscible, showing globular morphologies, whereas high-molar and side chains containing polysaccharides such as xanthan or tragacanth gum form co-continuous morphologies. The forming of blend fibres was nevertheless possible for all three solvents. The textile-physical properties of the blend fibres were slightly decreased compared to those of the unmodified fibre, in which fibres from NMMO and EMIMac had the highest performance. The presence of blended polysaccharides in the fibres produced was verified by residue sugar analysis, in which the highest amounts occurred for EMIMac fibres.


Martin C.,VTI Institute for Wood Technology and Wood Biology | Martin C.,University of Matanzas | Puls J.,VTI Institute for Wood Technology and Wood Biology | Saake B.,Sudan University of Science and Technology | Schreiber A.,Sudan University of Science and Technology
Cellulose Chemistry and Technology | Year: 2011

Sugarcane bagasse was pretreated with glycerol (40-80% (w/w)) either in the presence of NaOH or H 2SO 4, or without any chemicals, at 190 °C, 10% biomass load, for 1 to 4 hours. The pretreatments resulted in cellulose-enriched fibres and different degrees of xylan and lignin solubilisation. Cellulose recovery was higher in pretreatments with NaOH addition and without any chemicals, than in those with H 2SO 4. Xylan solubilisadon was almost complete in all H 2S0 4-assisted treatments whereas, in the other experiments, it decreased with the increase in glycerol concentration and increased with the pretreatment time. Lignin solubilisation increased proportionally with glycerol concentration. Under all conditions applied, the pretreatment improved the enzymatic hydrolysis of cellulose. The highest overall cellulose convertibilities were achieved in the glycerol pretreatments without other chemicals (85-94%). Convertibility decreased with time in acidic pretreatments, and increased slightly for the other ones. Enzymatic conversion of the xylan retained in the fibres was also detected.


Lopez Y.,University of Matanzas | Lopez Y.,University of Vigo | Gullon B.,University of Vigo | Puls J.,VTI Institute for Wood Technology and Wood Biology | And 3 more authors.
Holzforschung | Year: 2011

Rice hulls are potential low-cost feedstocks for fuel ethanol production in many countries. Most of the relevant publications are devoted to homogenous (high quality) hulls generated in industrial mills. On the other hand, small-scale mills give rise to hulls containing grain fragments and bran. In the present work, the dilute-acid pretreatment of such heterogeneous rice hulls was investigated based on a central composite rotatable experimental design. The variables were: temperature (140-210°C), biomass load (5-20%), and sulfuric acid concentration (0.5-1.5% based on reaction mixture). A total of 16 experimental runs were carried out, including a 23-plan, two replicates at the central point and six star points. Low temperatures were found to be favorable for the hydrolysis of xylan and of the easily hydrolyzable glucan fraction. High glucose formation (up to 15.3% of the raw material dry weight), attributable to starch hydrolysis, was detected in the hydrolysates obtained under the least severe pretreatment conditions. Several models were developed for predicting the effect of the operational conditions on the yield of pretreated solids, xylan and glucan conversion upon pretreatment, and on enzymatic convertibility of cellulose. The pretreatment temperature exerted the most significant effect on the conversion of the polysaccharides. Optimum results were predicted for the conversion of easily-hydrolyzable glucan in the material pretreated at 140.7°C, and for the enzymatic saccharification of cellulose in the material pretreated at 169°C. These results are interpreted that a two-step acid hydrolysis may be the best pretreatment strategy for heterogeneous rice hulls produced in small mills. © 2011 by Walter de Gruyter Berlin Boston.


Hernandez E.,University of Vigo | Hernandez E.,University of Matanzas | Garcia A.,University of Matanzas | Lopez M.,University of Matanzas | And 4 more authors.
Industrial Crops and Products | Year: 2013

In this work, dilute sulphuric acid prehydrolysis of residual empty pods of Moringa oleifera fruits was investigated as pretreatment for enzymatic hydrolysis of cellulose. In experiments performed at 130-190°C for 10-30min, corresponding to a severity range between log Ro=1.9 and logRo=4.2, the effect of pretreatment conditions on the recovery of polysaccharides and on the enzymatic convertibility of cellulose was evaluated. Overall cellulose recovery was above 95% in the pretreatments performed at 130 and 160°C, and between 87 and 90% in the pretreatments at 190°C, while xylan recovery in the most severe pretreatments was only 24.7-50.2%. The highest sugar concentration in the acid prehydrolysates (15.0g/L) was obtained in the pretreatment performed at 160°C and 20min. The formation of degradation products was low at mild pretreatment conditions, but it increased with the severity. Furfural concentration reached 4.04g/L at logRo=3.1 and decreased again with a further increase of the pretreatment severity. HMF, formic acid and levulinic acid were formed only in the most severe pretreatments. The pretreatment was effective for improving the enzymatic hydrolysis of cellulose, and the highest conversion (84.3%) was achieved in the material pretreated at mid severity (logRo=3.1). © 2012 Elsevier B.V.

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