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Xiaoming Huang, Jiadong Zhu, Tamás I Korányi, Michael D Boot, Emiel J M Hensen
Adding value to lignin, the most complex and recalcitrant fraction in lignocellulosic biomass, is highly relevant to costefficient operation of biorefineries. We report the use of homogeneous metal triflates to rapidly release lignin from biomass. Combined with metal-catalyzed hydrogenolysis, the process separates woody biomass into few lignin-derived alkylmethoxyphenols and cellulose under mild conditions. Model compound studies show the unique catalytic properties of metal triflates in cleaving lignin-carbohydrate interlinkages...
October 21, 2016: ChemSusChem
J T Oberlerchner, P Vejdovszky, T Zweckmair, A Kindler, S Koch, T Rosenau, A Potthast
Degraded celluloses are becoming increasingly important as part of product streams coming from various biorefinery scenarios. Analysis of the molar mass distribution of such fractions is a challenge, since neither established methods for mono- or disaccharides nor common methods for polysaccharide characterization cover the intermediate oligomer range appropriately. Size exclusion chromatography (SEC) with multi-angle laser light scattering (MALLS), the standard approach for celluloses, suffers from decreased scattering intensities in the lower-molar mass range...
October 8, 2016: Journal of Chromatography. A
Jean-Paul Lange
When investigating a new catalytic reaction, scientists may wonder if the crude reaction product can be easily separated and purified. We present here a new concept-distillation resistance-to assess the potential of distillation as a purification technique and to guide catalyst formulation or operation at the very early stage of the research. Distillation resistance, which has been developed from the analysis of 15 industrial distillation trains, can be quickly calculated with knowledge of only the product composition and atmospheric boiling points of the components...
October 20, 2016: ChemSusChem
S Raposo, A Constantino, F Rodrigues, B Rodrigues, M E Lima-Costa
Nowadays, bioethanol production is one of the most important technologies by the necessity to identify alternative energy resources, principally when based on inexpensive renewable resources. However, the costs of 2nd-generation bioethanol production using current biotechnologies are still high compared to fossil fuels. The feasibility of bioethanol production, by obtaining high yields and concentrations of ethanol, using low-cost medium, is the primary goal, leading the research done today. Batch Saccharomyces cerevisiae fermentation of high-density sugar from carob residues with different organic (yeast extract, peptone, urea) and inorganic nitrogen sources (ammonium sulfate, ammonium nitrate) was performed for evaluating a cost-effective ethanol production, with high ethanol yield and productivity...
October 19, 2016: Applied Biochemistry and Biotechnology
Katrin Ochsenreither, Claudia Glück, Timo Stressler, Lutz Fischer, Christoph Syldatk
Polyunsaturated fatty acids (PUFAs) of the ω-3 and ω-6 class (e.g., α-linolenic acid, linoleic acid) are essential for maintaining biofunctions in mammalians like humans. Due to the fact that humans cannot synthesize these essential fatty acids, they must be taken up from different food sources. Classical sources for these fatty acids are porcine liver and fish oil. However, microbial lipids or single cell oils, produced by oleaginous microorganisms such as algae, fungi and bacteria, are a promising source as well...
2016: Frontiers in Microbiology
Toshio Mori, Hiroko Kako, Tomoki Sumiya, Hirokazu Kawagishi, Hirofumi Hirai
A lactic acid (LA)-producing strain of the hyper-lignin-degrading fungus Phanerochaete sordida YK-624 with the lactate dehydrogenase-encoding gene from Bifidobacterium longum (Blldh) was constructed. When the endogenous pyruvate decarboxylase gene-knocked down and Blldh-expressing transformant was cultured with beech wood meal, the transformant was able to successively delignify and ferment the substrate. Supplementation of calcium carbonate into the culture medium, significantly increased the level of LA accumulation...
October 13, 2016: Journal of Biotechnology
Philippe Jacques, Max Béchet, Muriel Bigan, Delphine Caly, Gabrielle Chataigné, François Coutte, Christophe Flahaut, Egon Heuson, Valérie Leclère, Didier Lecouturier, Vincent Phalip, Rozenn Ravallec, Pascal Dhulster, Rénato Froidevaux
Innovations in novel enzyme discoveries impact upon a wide range of industries for which biocatalysis and biotransformations represent a great challenge, i.e., food industry, polymers and chemical industry. Key tools and technologies, such as bioinformatics tools to guide mutant library design, molecular biology tools to create mutants library, microfluidics/microplates, parallel miniscale bioreactors and mass spectrometry technologies to create high-throughput screening methods and experimental design tools for screening and optimization, allow to evolve the discovery, development and implementation of enzymes and whole cells in (bio)processes...
October 13, 2016: Bioprocess and Biosystems Engineering
Zhen Chen, Dehua Liu
As an inevitable by-product of the biofuel industry, glycerol is becoming an attractive feedstock for biorefinery due to its abundance, low price and high degree of reduction. Converting crude glycerol into value-added products is important to increase the economic viability of the biofuel industry. Metabolic engineering of industrial strains to improve its performance and to enlarge the product spectrum of glycerol biotransformation process is highly important toward glycerol biorefinery. This review focuses on recent metabolic engineering efforts as well as challenges involved in the utilization of glycerol as feedstock for the production of fuels and chemicals, especially for the production of diols, organic acids and biofuels...
2016: Biotechnology for Biofuels
Hugo Roume, Jan B A Arends, Camar P Ameril, Sunil A Patil, Korneel Rabaey
Given the large amount of crude glycerol formed as a by-product in the biodiesel industries and the concomitant decrease in its overall market price, there is a need to add extra value to this biorefinery side stream. Upgrading can be achieved by new biotechnologies dealing with recovery and conversion of glycerol present in wastewaters into value-added products, aiming at a zero-waste policy and developing an economically viable process. In microbial bioelectrochemical systems (BESs), the mixed microbial community growing on the cathode can convert glycerol reductively to 1,3-propanediol (1,3-PDO)...
2016: Frontiers in Bioengineering and Biotechnology
Omar Y Abdelaziz, Daniel P Brink, Jens Prothmann, Krithika Ravi, Mingzhe Sun, Javier García-Hidalgo, Margareta Sandahl, Christian P Hulteberg, Charlotta Turner, Gunnar Lidén, Marie F Gorwa-Grauslund
Lignin is a major component of lignocellulosic biomass and as such, it is processed in enormous amounts in the pulp and paper industry worldwide. In such industry it mainly serves the purpose of a fuel to provide process steam and electricity, and to a minor extent to provide low grade heat for external purposes. Also from other biorefinery concepts, including 2nd generation ethanol, increasing amounts of lignin will be generated. Other uses for lignin - apart from fuel production - are of increasing interest not least in these new biorefinery concepts...
October 6, 2016: Biotechnology Advances
Ailton Cesar Lemes, Gabriel Teixeira Álvares, Mariana Buranelo Egea, Adriano Brandelli, Susana Juliano Kalil
The use of processes for simultaneous production of bioproducts as enzymes and bioactive compounds is an interesting alternative to reduce environmental impacts. Thus, the aim of this study was to produce simultaneously, using the biorefinery concept, both proteases and bioactive compounds with antioxidant activity from Bacillus sp. P45 cultivation by using different by-products. The integrated process developed in this study enabled to obtain enzymes with proteolytic and keratinolytic properties in a process with alternate substrates from agro-industrial by-products (feather meal, residual feather meal and biomass), thus, creating an interesting alternative to managing them...
October 3, 2016: Bioresource Technology
Han-Yin Li, Chen-Zhou Wang, Xue Chen, Xue-Fei Cao, Shao-Ni Sun, Run-Cang Sun
An integrated process based on ionic liquids ([Bmim]Cl and [Bmim]OAc) pretreatment and successive alkali post-treatments (0.5, 2.0, and 4.0% NaOH at 90°C for 2h) was performed to isolate lignins from Eucalyptus. The structural features and spatial distribution of lignin in the Eucalyptus cell wall were investigated thoroughly. Results revealed that the ionic liquids pretreatment promoted the isolation of alkaline lignin from the pretreated samples without obvious structural changes. Additionally, the integrated process resulted in syringyl-rich lignin macromolecules with more β-O-4' linkages and less phenolic hydroxyl groups...
September 29, 2016: Bioresource Technology
Laura Capolupo, Vincenza Faraco
Lignocellulosic biomass is the most abundant, low-cost, bio-renewable resource that holds enormous importance as alternative source for production of biofuels and other biochemicals that can be utilized as building blocks for production of new materials. Enzymatic hydrolysis is an essential step involved in the bioconversion of lignocellulose to produce fermentable monosaccharides. However, to allow the enzymatic hydrolysis, a pretreatment step is needed in order to remove the lignin barrier and break down the crystalline structure of cellulose...
October 6, 2016: Applied Microbiology and Biotechnology
Kentaro Inokuma, Tomohisa Hasunuma, Akihiko Kondo
N-acetyl-D-glucosamine (GlcNAc) is the building block of chitin, which is one of the most abundant renewable resources in nature after cellulose. Therefore, a microorganism that can utilize GlcNAc is necessary for chitin-based biorefinery. In this study, we report on the screening and characterization of yeast strains for bioethanol production from GlcNAc. We demonstrate that Scheffersomyces (Pichia) stipitis strains can use GlcNAc as the sole carbon source and produce ethanol. S. stipitis NBRC1687, 10007, and 10063 strains consumed most of the 50 g/L GlcNAc provided, and produced 14...
December 2016: AMB Express
Ji-Min Woo, Ji-Won Kim, Ji-Won Song, Lars M Blank, Jin-Byung Park
The biosynthesis of carboxylic acids including fatty acids from biomass is central in envisaged biorefinery concepts. The productivities are often, however, low due to product toxicity that hamper whole-cell biocatalyst performance. Here, we have investigated factors that influence the tolerance of Escherichia coli to medium chain carboxylic acid (i.e., n-heptanoic acid)-induced stress. The metabolic and genomic responses of E. coli BL21(DE3) and MG1655 grown in the presence of n-heptanoic acid indicated that the GadA/B-based glutamic acid-dependent acid resistance (GDAR) system might be critical for cellular tolerance...
2016: PloS One
Xingguang Zhang, Karen Wilson, Adam F Lee
Biomass has been long exploited as an anthropogenic energy source; however, the 21st century challenges of energy security and climate change are driving resurgence in its utilization both as a renewable alternative to fossil fuels and as a sustainable carbon feedstock for chemicals production. Deconstruction of cellulose and hemicellulose carbohydrate polymers into their constituent C5 and C6 sugars, and subsequent heterogeneously catalyzed transformations, offer the promise of unlocking diverse oxygenates such as furfural, 5-hydroxymethylfurfural, xylitol, sorbitol, mannitol, and gluconic acid as biorefinery platform chemicals...
October 12, 2016: Chemical Reviews
Ramkumar B Nair, Mohammad J Taherzadeh
The aim of the present work was to study the integration of edible ascomycetes filamentous fungi into the existing sugar- or molasses-to-ethanol processes, to grow on vinasse or stillage and produce ethanol and protein-rich fungal biomass. Two fungal strains, Neurospora intermedia and Aspergillus oryzae were examined in shake flasks and airlift-bioreactors, resulting in reduction of vinasse COD by 34% and viscosity by 21%. Utilization of glycerol and sugars were observed, yielding 202.4 or 222.8g dry fungal biomass of N...
December 2016: Bioresource Technology
Yang Xing, Lingxi Bu, Tianran Zheng, Shijie Liu, Jianxin Jiang
Co-production of glucose, furfural and other green materials based on a lignocellulosic biorefinery is a promising way to realize the commercial application of corncob residues. An effective process was developed for glucose production using low temperature bisulfite pretreatment and high-solids enzymatic hydrolysis. Corncob residues from furfural production (FRs) were pretreated with 0.1g NaHSO3/g dry substrate at 100°C for 3h. Lignin was sulfonated and sulfonic groups were produced during pretreatment, which resulted in decreasing the zeta potential of the samples...
December 2016: Bioresource Technology
Amparo Jiménez-Quero, Eric Pollet, Minjie Zhao, Eric Marchioni, Luc Averous, Vincent Phalip
The production of high-value chemicals from natural resources as alternative of petroleum-based products is currently expanding in parallel with biorefinery. The use of lignocellulosic biomass as raw material is promising to achieve economic and environmental sustainability. Filamentous fungi, particularly Aspergillus species, are already used industrially to produce organic acid as well as many enzymes. The production of lignocellulose degrading enzymes opens the possibility for direct fungal fermentation towards organic acids as itaconic and fumaric acids...
September 23, 2016: Journal of Microbiology and Biotechnology
Sol Choi, Hyun Uk Kim, Tae Yong Kim, Sang Yup Lee
To address climate change and environmental problems, it is becoming increasingly important to establish biorefineries for the production of chemicals from renewable non-food biomass. Here we report the development of Escherichia coli strains capable of overproducing a four-carbon platform chemical 4-hybroxybutyric acid (4-HB). Because 4-HB production is significantly affected by aeration level, genome-scale metabolic model-based engineering strategies were designed under aerobic and microaerobic conditions with emphasis on oxidative/reductive TCA branches and glyoxylate shunt...
September 20, 2016: Metabolic Engineering
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