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Category Archives: Biotechnology

Elucidating the role of ferrous ion cocatalyst in enhancing dilute acid pretreatment of lignocellulosic biomass

Background:
Recently developed iron co-catalyst enhancement of dilute-acid pretreatment of biomass is a promising approach for enhancing sugar release from recalcitrant lignocellulosic biomass. However, very little is known about the underlying mechanisms of this enhancement. Here, our aim was to identify several essential factors that contribute to ferrous ion-enhanced efficiency during dilute-acid pretreatment of biomass and to initiate the investigation of the mechanisms that result in this enhancement.
Results:
During dilute-acid and ferrous ion co-catalyst pretreatments, we observed concomitant increases in solubilized sugars in the hydrolysate and reducing sugars in the (insoluble) biomass residues. We also observed enhancements in sugar release during subsequent enzymatic saccharification of iron co-catalyst pretreated biomass. Fourier transform Raman spectroscopy showed that major peaks representing the C-O-C and C-H bonds in cellulose are significantly attenuated by iron co-catalyst pretreatment. Imaging by Prussian blue staining indicates that Fe2+ ions associate with both cellulose/xylan and lignin in the untreated as well as dilute-acid/Fe2+ ion pretreated corn stover samples. Analyses by scanning electron microscopy and transmission electron microscopy reveal structural details of biomass after dilute-acid/Fe2+ ion pretreatment, in which the delamination and fibrillation of cell wall were observed.
Conclusions:
Using this multi-modal approach, we have revealed that (1) acid-ferrous ion assisted pretreatment increased solubilization and enzymatic digestion of both cellulose and xylan to monomers, and (2) this pretreatment likely targets multiple chemistries in plant cell wall polymer networks, including those represented by the C-O-C and C-H bonds in cellulose.Source:
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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

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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BIO: Similarities between Australia

James Greenwood, President

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BIO: Similarities between Australia

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CFEDC Presents: MARBIONIC Marine Biotechnology June 23, 2010 1 of 3 – Video

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 1 of 3 - Video

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Breakthrough in Biotechnology with Orange County Schools / BioForum – Video

Panelists: Dr.

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Breakthrough in Biotechnology with Orange County Schools / BioForum - Video

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Biotechnology In India – Video

A snapshot of the biotechnology industry in India

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Biotechnology In India - Video

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