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Li X.,University of Georgia | Li X.,Nanjing Forestry University | Li X.,Jiangsu Key Laboratory of Biomass Based Green Fuels and Chemicals | Huang Y.,University of Georgia | Whitman W.B.,University of Georgia
Antonie van Leeuwenhoek, International Journal of General and Molecular Microbiology | Year: 2015

In the original proposal of Wayne et al. (Int J Syst Bacteriol 37:463–464, 1987), two measures of genetic relatedness were proposed to set the boundary for prokaryotic species. The first was the change in the melting temperature (ΔTm) of heteroduplex DNA and the second was the extent of DNA–DNA hybridization (DDH). While this approach was justified given the experimental error inherent in these methods, genomic sequencing has the potential to measure both parameters with great precision. The average nucleotide identity (ANIb), a surrogate for the ΔTm, and the calculated DDH (cDDH) were determined from the complete genomes of representatives of 17 genera of prokaryotes. When the ANIb was >75 %, the ratio (100-cDDH)/(100-ANIb) was 3.69 ± 0.93 (± SD) and varied from about 2.35 to 4.59 between genera. The differences among genera was highly significant (p < 0.001) but not correlated with specific phylogenetic or physiological groups. Moreover, the ANIm was a poor measure of ANIb when ANIb was <75 %. Because the ANIb and cDDH provide different measures of relatedness, it is no longer appropiate to consider both when delineating species. For these reasons, measures of relatedness based upon sequence identity should be used for delineating species in the future. © 2014, Springer International Publishing Switzerland. Source


Ouyang J.,Jiangsu Key Laboratory of Biomass Based Green Fuels and Chemicals | Liu B.,Nanjing Forestry University | Zhang M.,Nanjing Forestry University | Zheng Z.,Nanjing Forestry University | Yu H.,Nanjing Forestry University
Bioresource Technology | Year: 2013

The high costs of enzymatic hydrolysis along with the high enzyme dosage are often considered as the major bottlenecks in lignocellulosic bioconversion. This study investigated the hydrolysis efficiency, cellulase adsorption and enzyme recycling during the hydrolysis of bagasse sulfite pulp (BSP). After 48. h of hydrolysis, more than 70% of the cellulose was hydrolyzed, while the protein concentration and cellulase activity in solution remained 31% and 17% of the initial value, respectively. The cellulase adsorption on the fresh BSP was better fitted by a Sips model, suggesting the occurrence of a multilayer adsorption at low cellulase concentration and monolayer adsorption at high concentration on the BSP surfaces. Desorption profile studies showed that the optimum desorption condition was at pH 4.8 and 40. °C. Moreover, considering the limited ability to desorption, directly empolying the bound enzyme with residual substrate is more effective method to recover cellulase during the hydrolysis of BSP. © 2013 . Source


Wang X.,Nanjing Forestry University | Xu Y.,Nanjing Forestry University | Xu Y.,Jiangsu Key Laboratory of Biomass Based Green Fuels and Chemicals | Lian Z.,Nanjing Forestry University | And 2 more authors.
Journal of Wood Chemistry and Technology | Year: 2014

Interest in biomass biorefineries and especially their aldonic acid products has been growing in recent years. However, the analytical methods for aldonic acids have only rarely been explored. In this study, a simple one-step method was developed using high-performance anion-exchange chromatography coupled with pulsed amperometric detection (HPAEC-PAD).With this method, five wood monosaccharides and their corresponding aldonic acids, including arabinose, galactose, glucose, xylose, mannose, arabonic acid, galactonic acid, gluconic acid, xylonic acid, and mannonic acid, were simultaneously separated and quantitatively determined. The separation was performed on a CarboPac™ PA-10 column (250 mm × 2 mm) with a gradient elution using NaOH solution as the mobile phase. The calibration curves showed good linearity (R2 ≥ 0.9993) for the five monosaccharides and the corresponding aldonic acids in the range of 0.1 to 10.0 mg/L. The spiked recoveries of the 10 components ranged from 93.92% to 104.15%, with relative standard deviations (RSDs) (n = 3) of 0.49% to 3.95%. The established method was applied successfully to determine the quantitative variation of monosaccharide and aldonic acid contents in products from a biomass biorefinery. Copyright © Taylor & Francis Group, LLC. Source


Wang X.,Nanjing Forestry University | Xu Y.,Nanjing Forestry University | Xu Y.,Jiangsu Key Laboratory of Biomass Based Green Fuels and Chemicals | Fan L.,Nanjing Forestry University | And 2 more authors.
BioResources | Year: 2012

A method for simultaneous separation and quantitative determination of arabinose, galactose, glucose, xylose, xylonic acid, gluconic acid, galacturonic acid, and glucuronic acid was developed by using high performance anion-exchange chromatography coupled with pulsed amperometric detection (HPAEC-PAD). The separation was performed on a CarboPac™ PA-10 column (250 mm × 2 mm) with a various gradient elution of NaOH-NaOAc solution as the mobile phase. The calibration curves showed good linearity (R2 ≥ 0.9993) for the monosaccharides, uronic acids, and aldonic acids in the range of 0.1 to 12.5 mg/L. The detection limits (LODs) and the quantification limits (LOQs) were 4.91 to 18.75 μg/L and 16.36 to 62.50 μg/L, respectively. Relative standard deviations (RSDs) of the retention times and peak areas for the seven consecutive determinations of an unknown amount of mixture were 0.15% to 0.44% and 0.22% to 2.31%, respectively. The established method was used to separate and determine four monosaccharides, two uronic acids, and two aldonic acids in the prehydrolysate from dilute acid steam-exploded corn stover within 21 min. The spiked recoveries of monosaccharides, uronic acids, and aldonic acids ranged from 91.25% to 108.81%, with RSDs (n=3) of 0.04% ~ 6.07%. This method was applied to evaluate the quantitative variation of sugar and sugar acid content in biomass prehydrolysates. Source


Du L.,Nanjing Forestry University | Yang S.,Nanjing Forestry University | Xu L.,Nanjing Forestry University | Xu L.,Jiangsu Key Laboratory of Biomass Based Green Fuels and Chemicals | And 2 more authors.
CrystEngComm | Year: 2014

A microporous acylamide-functionalized metal-organic framework with a kgm-pillared structure, [Cu(NAIP2-)]n, has been designed by self-assembling [Cu2(COO)4] paddlewheel SBUs and a novel trigonal heterofunctional ligand with a linking acylamide group. [Cu(NAIP2-)]n exhibits a moderate BET surface area of 1060 m2 g-1, high CO2 uptake (4.5 wt% at 0.15 bar and 298 K; 201.8 cm3 g-1 at 20 bar and 298 K) and high selectivity for CO2 over CH4 (8.34) and N2 (38.3) at 273 K. © the Partner Organisations 2014. Source

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