Chemical and morphological characterization of sugarcane bagasse submitted to delignification process for enhanced enzymatic digestibility

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Background:
In the recent years, biorefining of lignocellulosic biomass to produce multi-products such as ethanol and other biomaterials has become a dynamic research area. Pretreatment technologies that fractionate sugarcane bagasse are essential for the successful use of this feedstock in ethanol production. In this paper, we investigate modifications in morphology and chemical composition of sugarcane bagasse, submitted to a two-step treatment using diluted acid, followed by a delignification process with increasing sodium hydroxide concentrations. Detailed chemical and morphological characterization of the samples after each pretreatment condition, studied by HPLC, solid-state NMR, DRIFT and SEM, is reported, together with sample crystallinity and enzymatic digestibility.
Results:
Chemical composition analysis performed on samples obtained after different pretreatment conditions showed that up to 96% and 85% of hemicellulose and lignin fractions, respectively, were removed by this two-step method, when sodium hydroxide concentrations of 1% (m/v) or higher were used. The efficient lignin removal resulted in an enhanced hydrolysis yield reaching values around 100%. Considering the cellulose loss due to the pretreatment (maximum of 30%, depending on the process), the total cellulose conversion increases significantly from 22.0% (value for the untreated bagasse) to 72.4%. The delignification process, with consequent increase in the cellulose/lignin ratio, is also clearly observed by NMR and DRIFT experiments. We also demonstrated that the morphological changes contributing to this remarkable improvement occur as a consequence of lignin removal from the sample. Bagasse unstructuring is favored by the loss of cohesion between neighboring cell walls, as well as by the changes in the inner cell wall structure, such as damaging, hole formation and loss of mechanical resistance, facilitating liquid and enzyme access to crystalline cellulose.
Conclusions:
The results presented herewith show the efficiency of the proposed method for improving the enzymatic digestibility of sugarcane bagasse and provide understanding of the pretreatment action mechanism. Combining the different techniques applied in this work warranted thorough information about the undergoing morphological and chemical changes and was an efficient approach to understand the morphological effects resulting from sample delignification and its influence on the enhanced hydrolysis results.Source:
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Composition and hydrothermal pretreatment and enzymatic saccharification performance of grasses and legumes from a mixed species prairie

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Background:
Mixtures of prairie species (mixed prairie species; MPS) have been proposed to offer important advantages as a feedstock for sustainable production of fuels and chemicals. Therefore, understanding the performance in hydrothermal pretreatment and enzymatic hydrolysis of select species harvested from a mixed prairie is valuable in selecting these components for such applications. This study examined composition and sugar release from the most abundant components of a plot of MPS: a C3 grass (Poa pratensis), a C4 grass (Schizachyrium scoparium), and a legume (Lupinus perennis). Results from this study provide a platform to evaluate differences between grass and leguminous species, and the factors controlling their recalcitrance to pretreatment and enzymatic hydrolysis.
Results:
Significant differences were found between the grass and leguminous species, and between the individual anatomical components that influence the recalcitrance of MPS. We found that both grasses contained higher levels of sugars than did the legume, and also exhibited higher sugar yields as a percentage of the maximum possible from combined pretreatment and enzymatic hydrolysis. Furthermore, particle size, acid-insoluble residue (AcIR), and xylose removal were not found to have a direct significant effect on glucan digestibility for any of the species tested, whereas anatomical composition was a key factor in both grass and legume recalcitrance, with the stems consistently exhibiting higher recalcitrance than the other anatomical fractions.
Conclusions:
The prairie species tested in this study responded well to hydrothermal pretreatment and enzymatic saccharification. Information from this study supports recommendations as to which plant types and species are more desirable for biological conversion in a mixture of prairie species, in addition to identifying fractions of the plants that would most benefit from genetic modification or targeted growth.Source:
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Pretreatment of microcrystalline cellulose in organic electrolyte solutions for enzymatic hydrolysis

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Background:
Previous studies have shown that the crystalline structure of cellulose is negatively correlated with enzymatic digestibility, therefore, pretreatment is required to break down the highly ordered crystalline structure in cellulose, and to increase the porosity of its surface. In the present study, an organic electrolyte solution (OES) composed of an ionic liquid (1-allyl-3-methylimidazolium chloride ([AMIM]Cl) and an organic solvent (dimethyl sulfoxide; DMSO) was prepared, and used to pretreat microcrystalline cellulose for subsequent enzymatic hydrolysis; to our knowledge, this is the first time that this method has been used.
Results:
Microcrystalline cellulose (5 wt%) rapidly dispersed and then completely dissolved in an OES with a molar fraction of [AMIM]Cl per OES (chi [AMIM]Cl) of greater than or equal to 0.2 at 110 degrees centigrade within 10 minutes. The cellulose was regenerated from the OES by precipitation with hot water, and enzymatically hydrolyzed. As the chi [AMIM]Cl of the OES increased from 0.1 to 0.9, both the hydrolysis yield and initial hydrolysis rate of the regenerated cellulose also increased gradually. After treatment using OES with chi [AMIM]Cl of 0.7, the glucose yield (54.1%) was 7.2 times that of untreated cellulose. This promotion of hydrolysis yield was mainly due to the decrease in the degree of crystallinity (that is, the crystallinity index of cellulose I).
Conclusions:
An OES of [AMIM]Cl and DMSO with chi [AMIM]Cl of 0.7 was chosen for cellulose pretreatment because it dissolved cellulose rapidly to achieve a high glucose yield (54.1%), which was only slightly lower than the value (59.6%) obtained using pure [AMIM]Cl. OES pretreatment is a cost-effective and environmentally friendly technique for hydrolysis, because it 1) uses the less expensive OES instead of pure ionic liquids, 2) shortens dissolution time, 3) requires lower energy for stirring and transporting, and 4) is recyclable.Source:
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Future of Health Care – medical, health and hospital trends – Biotechnology company keynote 2002 by – Video

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2002 Lecture by Dr Patrick Dixon, ranked as one of the 20 most influential business thinkers alive today (Thinkers 50 2005). Health care trends, future of pharmaceutical industry, biotechnology, stem cells, human cloning, organ regeneration, longevity, ageing, negligible senescence.

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Future of Health Care - medical, health and hospital trends - Biotechnology company keynote 2002 by - Video

Functional characterization and target discovery of Glycoside Hydrolases from Lower Termite Coptotermes gestroi Digestome

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Background:
Lignocellulosic materials have been moved towards the forefront of the biofuel industry as a sustainable resource. However, saccharification and production of bioproducts derived from plant cell wall biomass are complex and entail lengthy processes. The understanding of a termite gut biology and feeding strategies may improve the current state of biomass conversion technology and bioproduct production.
Results:
The study herein shows comprehensive functional characterization of crude body extracts from C. gestroi along with global proteomic analysis of the termite's digestome, targeting the identification of glycoside hydrolases (GH) and accessory proteins responsible for plant biomass conversion. The crude protein extract from C. gestroi was enzymatically efficient over a broad pH range on a series of natural polysaccharides, formed by glucose-, xylose-, mannan- and/or arabinose-containing polymers, linked by various types of glycosydic bonds, as well as ramification types. Our proteomic approach successfully identified a large number of relevant polypeptides in the C. gestroi digestome. A total of 55 different proteins were identified and classified into 29 CAZy families. Based on the total number of peptides identified, the majority of components found in the C. gestroi digestome were cellulose-degrading enzymes. Xylanolytic enzymes, mannan- hydrolytic enzymes, pectinases, and starch-degrading and debranching enzymes were also identified. Our strategy enabled validation of LC-MS/MS recognized proteins, by enzymatic functional assays and following degradation products of specific APTS labeled oligosaccharides through capillary zone electrophoresis.
Conclusions:
Here we describe the first global study about the enzymatic repertoire involved in plant polysaccharide degradation by the lower termite C. gestroi. The biochemical characterization of whole body termite extracts evidenced the ability to cleave all types of glycosidic bonds present in plant polysaccharides. The comprehensive proteomic analysis, revealed a complete collection of hydrolytic enzymes including cellulases (GH1, GH3, GH5, GH7, GH9 and CBM 6), hemicellulases (GH2, 10, 11, 16, 43 and CBM 27) and pectinases (GH28 and GH29).Source:
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High throughput screening of hydrolytic enzymes from termites using a natural substrate derived from sugar cane bagasse

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Background:
The description of new hydrolytic enzymes is an important step in the development of techniques to use lignocellulosic materials as a starting point for fuel production. Sugarcane bagasse, which is subjected to pre-treatment, hydrolysis and fermentation for the production of ethanol in several test refineries, is the most promising source of raw material for the production of 2nd generation renewable fuels in Brazil. One problem when screening hydrolytic activities is that the activity against commercial substrates such as carboxymethylcellulose does not always correspond to the activity against the natural lignocellulosic material. Besides that, the macroscopic characteristics of the raw material such as insolubility and heterogeneity hinder its use for high throughput screenings.
Results:
In this paper, we present the preparation of a colloidal suspension of particles obtained from sugarcane bagasse, with minimal chemical change in the lignocellulosic material, and demonstrate its use for high throughput assays of hydrolases using Brazilian termites as screened organisms.
Conclusions:
Important differences between the use of the natural substrate and commercial cellulase substrates such as CMC or crystalline cellulose were observed, suggesting that wood feeding termites, in contrast to litter feeding ones, might not be the best source for enzymes that degrade sugarcane biomass.Source:
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Future of Biotechnology Panel (Part I) – Video

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A panel discussion on the future of biotechnology, with three leaders in the field: -Stuart Kim, Professor of Developmental Biology and Genetics, Stanford University -Michael Snyder, Professor and Chair of Genetics, Stanford University, Director of the Stanford Center for Genetics and Personalized Medicine -David Haussler, Professor of Biomolecular Engineering and Director of the Center for Biomolecular Science and Engineering at UC Santa Cruz. Filmed at the Executive Program at Singularity University, NASA Ames Research Center, Silicon Valley, CA.

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Future of Biotechnology Panel (Part I) - Video

Pursuing different Immunodrug™ programs/Dr Alexander Link-Cytos Biotechnology-World Vaccine Congre – Video

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Subscribe:www.youtube.com Pursuing in different Immunodrug™ programs • Pursuing in different Immunodrug™ programs addressing important chronic disease indications and clinical proof of concept

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Pursuing different Immunodrug™ programs/Dr Alexander Link-Cytos Biotechnology-World Vaccine Congre - Video

A strain of Saccharomyces cerevisiae evolved for fermentation of lignocellulosic biomass displays improved growth and fermentative ability in high solids concentrations and in the presence of inhibitory compounds

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Background:
Softwoods are the dominant source of lignocellulosic biomass in the Northern hemisphere and have been investigated world-wide as a renewable substrate for cellulosic ethanol production. One challenge to using softwoods, particularly acute with pine, is that the pretreatment process produces inhibitory compounds detrimental to growth and metabolic activity of fermenting organisms. To overcome the challenge of bioconversion in the presence of inhibitory compounds, especially at high solids loading, a strain of Saccharomyces cerevisiae was subjected to evolutionary engineering and adaptation using pretreated pine wood (Pinus taeda).
Results:
An industrial strain of Saccharomyces cerevisiae, XR122N, was evolved using pretreated pine; the resulting daughter strain, AJP50, produced ethanol much more rapidly than its parent in fermentations of pretreated pine. Adaptation by preculturing of the industrial yeast XR122N and the evolved strains in 7% w/v pretreated pine solids prior to inoculation into higher solids concentrations, improved fermentation performance of all strains compared to direct inoculation into high solids. Growth comparisons between XR122N and AJP50 in model hydrolysate media containing inhibitory compounds found in pretreated biomass, revealed AJP50 exited lag phase faster under all conditions tested. This ability is due, in part, to AJP50 rapidly converting furfural and hydroxymethylfurfural to their less toxic alcohol derivatives and recovering from reactive oxygen species damage more quickly than XR122N. Under industrially relevant conditions of 17.5% w/v pretreated pine solids loading, additional evolutionary engineering was required to decrease the pronounced lag phase. Using a combination of adaptation by inoculation first into a solids loading of 7% w/v for 24 h, followed by a 10% v/v inoculum (approximately 1 g/L dry cell wt) into 17.5% w/v solids, the final strain (AJP50) produced ethanol at >80% of the maximum theoretical yield after 72 h of fermentation and reached >90% of the maximum theoretical yield after 120 h of fermentation.
Conclusions:
Our results demonstrate that fermentations of pretreated pine containing liquid and solids, including any inhibitory compounds generated during pretreatment, are possible at higher solids loadings than previously reported in the literature. These fermentations demonstrated reduced inoculum sizes and shortened process times, thereby improving the overall economic viability of a pine-to-ethanol conversion process.Source:
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CFEDC Presents: MARBIONIC Marine Biotechnology June 23, 2010 2 of 3 – Video

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MARBIONC's vision is to "position North Carolina's marine biotechnology industry as a key component in reaching economic and environmental solutions on a global scale." After MARBIONC, Scott Baker from UNCW's Center for Marine Sciences (CMS) and North Carolina Sea Grant spoke about efforts to create community supported seafood projects (CSS).

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CFEDC Presents: MARBIONIC Marine Biotechnology June 23, 2010 2 of 3 - Video