Dataset Information

Acidic pretreatment of wheat straw in decanol for the production of surfactant, lignin and glucose.

ABSTRACT: Wheat straw is an abundant residue of agriculture which is increasingly being considered as feedstock for the production of fuels, energy and chemicals. The acidic decanol-based pre-treatment of wheat straw has been investigated in this work. Wheat straw hemicellulose has been efficiently converted during a single step operation into decyl pentoside surfactants and the remaining material has been preserved keeping all its promises as potential feedstock for fuels or value added platform chemicals such as hydroxymethylfurfural (HMF). The enzymatic digestibility of the cellulose contained in the straw residue has been evaluated and the lignin prepared from the material characterized. Wheat-based surfactants thus obtained have exhibited superior surface properties compared to fossil-based polyethoxylates decyl alcohol or alkyl oligoglucosides, some of which are largely used surfactants. In view of the growing importance of renewable resource-based molecules in the chemical industry, this approach may open a new avenue for the conversion of wheat straw into various chemicals.

SUBMITTER: Marinkovic S

PROVIDER: S-EPMC3269690 | biostudies-literature | 2012

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Acidic pretreatment of wheat straw in decanol for the production of surfactant, lignin and glucose.

Marinkovic Sinisa S Le Bras Jean J Nardello-Rataj Véronique V Agach Mickaël M Estrine Boris B

International journal of molecular sciences 20111228 1

Wheat straw is an abundant residue of agriculture which is increasingly being considered as feedstock for the production of fuels, energy and chemicals. The acidic decanol-based pre-treatment of wheat straw has been investigated in this work. Wheat straw hemicellulose has been efficiently converted during a single step operation into decyl pentoside surfactants and the remaining material has been preserved keeping all its promises as potential feedstock for fuels or value added platform chemical ...[more]

PMID: 22312256

Similar Datasets

Project description:BackgroundIn this study, the dilute maleic acid pretreatment of wheat straw is optimized, using pretreatment time, temperature and maleic acid concentration as design variables. A central composite design was applied to the experimental set up. The response factors used in this study are: (1) glucose benefits from improved enzymatic digestibility of wheat straw solids; (2) xylose benefits from the solubilization of xylan to the liquid phase during the pretreatment; (3) maleic acid replenishment costs; (4) neutralization costs of pretreated material; (5) costs due to furfural production; and (6) heating costs of the input materials. For each response factor, experimental data were fitted mathematically. After data translation to euro/Mg dry straw, determining the relative contribution of each response factor, an economic optimization was calculated within the limits of the design variables.ResultsWhen costs are disregarded, an almost complete glucan conversion to glucose can be reached (90% from solids, 7%-10% in liquid), after enzymatic hydrolysis. During the pretreatment, up to 90% of all xylan is converted to monomeric xylose. Taking cost factors into account, the optimal process conditions are: 50 min at 170 degrees C, with 46 mM maleic acid, resulting in a yield of 65 euro/Mg (megagram = metric ton) dry straw, consisting of 68 euro/Mg glucose benefits (from solids: 85% of all glucan), 17 euro/Mg xylose benefits (from liquid: 80% of all xylan), 17 euro/Mg maleic acid costs, 2.0 euro/Mg heating costs and 0.68 euro/Mg NaOH costs. In all but the most severe of the studied conditions, furfural formation was so limited that associated costs are considered negligible.ConclusionsAfter the dilute maleic acid pretreatment and subsequent enzymatic hydrolysis, almost complete conversion of wheat straw glucan and xylan is possible. Taking maleic acid replenishment, heating, neutralization and furfural formation into account, the optimum in the dilute maleic acid pretreatment of wheat straw in this study is 65 euro/Mg dry feedstock. This is reached when process conditions are: 50 min at 170 degrees C, with a maleic acid concentration of 46 mM. Maleic acid replenishment is the most important of the studied cost factors.

Project description:BackgroundThe use of the enzymatic hydrolysis of lignocellulose with subsequent fermentation to ethanol provides a green alternative for the production of transportation fuels. Because of its recalcitrant nature, the lignocellulosic biomass must be pretreated before enzymatic hydrolysis. However, the pretreatment often results in the formation of compounds that are inhibitory for the enzymes or fermenting organism. Although well recognized, little quantitative information on the inhibition of individual cellulase components by identified inhibitors is available.ResultsStrong cellulase inhibitors were separated from the liquid fraction of the hydrothermal pretreatment of wheat straw. HPLC and mass-spectroscopy analyses confirmed that the inhibitors were oligosaccharides (inhibitory oligosaccharides, IOS) with a degree of polymerization from 7 to 16. The IOS are composed of a mixture of xylo- (XOS) and gluco-oligosaccharides (GOS). We propose that XOS and GOS are the fragments of the xylan backbone and mixed-linkage β-glucans, respectively. The IOS were approximately 100 times stronger inhibitors for Trichoderma reesei cellobiohydrolases (CBHs) than cellobiose, which is one of the strongest inhibitors of these enzymes reported to date. Inhibition of endoglucanases (EGs) by IOS was weaker than that of CBHs. Most of the tested cellulases and hemicellulases were able to slowly degrade IOS and reduce the inhibitory power of the liquid fraction to some extent. The most efficient single enzyme component here was T. reesei EG TrCel7B. Although reduced by the enzyme treatment, the residual inhibitory power of IOS and the liquid fraction was strong enough to silence the major component of the T. reesei cellulase system, CBH TrCel7A.ConclusionsThe cellulase inhibitors described here may be responsible for the poor yields from the enzymatic conversion of the whole slurries from lignocellulose pretreatment under conditions that do not favor complete degradation of hemicellulose. Identification of the inhibitory compounds helps to design better enzyme mixtures for their degradation and to optimize the pretreatment regimes to minimize their formation.

Project description:BackgroundFatty acid-derived products such as fatty alcohols (FAL) find growing application in cosmetic products, lubricants, or biofuels. So far, FAL are primarily produced petrochemically or through chemical conversion of bio-based feedstock. Besides the well-known negative environmental impact of using fossil resources, utilization of bio-based first-generation feedstock such as palm oil is known to contribute to the loss of habitat and biodiversity. Thus, the microbial production of industrially relevant chemicals such as FAL from second-generation feedstock is desirable.ResultsTo engineer Corynebacterium glutamicum for FAL production, we deregulated fatty acid biosynthesis by deleting the transcriptional regulator gene fasR, overexpressing a fatty acyl-CoA reductase (FAR) gene of Marinobacter hydrocarbonoclasticus VT8 and attenuating the native thioesterase expression by exchange of the ATG to a weaker TTG start codon. C. glutamicum ∆fasR cg2692TTG (pEKEx2-maqu2220) produced in shaking flasks 0.54 ± 0.02 gFAL L-1 from 20 g glucose L-1 with a product yield of 0.054 ± 0.001 Cmol Cmol-1. To enable xylose utilization, we integrated xylA encoding the xylose isomerase from Xanthomonas campestris and xylB encoding the native xylulose kinase into the locus of actA. This approach enabled growth on xylose. However, adaptive laboratory evolution (ALE) was required to improve the growth rate threefold to 0.11 ± 0.00 h-1. The genome of the evolved strain C. glutamicum gX was re-sequenced, and the evolved genetic module was introduced into C. glutamicum ∆fasR cg2692TTG (pEKEx2-maqu2220) which allowed efficient growth and FAL production on wheat straw hydrolysate. FAL biosynthesis was further optimized by overexpression of the pntAB genes encoding the membrane-bound transhydrogenase of E. coli. The best-performing strain C. glutamicum ∆fasR cg2692TTG CgLP12::(Ptac-pntAB-TrrnB) gX (pEKEx2-maqu2220) produced 2.45 ± 0.09 gFAL L-1 with a product yield of 0.054 ± 0.005 Cmol Cmol-1 and a volumetric productivity of 0.109 ± 0.005 gFAL L-1 h-1 in a pulsed fed-batch cultivation using wheat straw hydrolysate.ConclusionThe combination of targeted metabolic engineering and ALE enabled efficient FAL production in C. glutamicum from wheat straw hydrolysate for the first time. Therefore, this study provides useful metabolic engineering principles to tailor this bacterium for other products from this second-generation feedstock.

Dataset Information

Acidic pretreatment of wheat straw in decanol for the production of surfactant, lignin and glucose.

Publications

Acidic pretreatment of wheat straw in decanol for the production of surfactant, lignin and glucose.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets