Oligosaccharide Mass Profiling (OLIMP) allows a fast and sensitive assessment of cell wall polymer structure when coupled with Matrix Assisted Laser Desorption Ionisation Time Of Flight Mass Spectrometry (MALDI-TOF MS). The short time required for sample preparation and analysis makes possible the study of a wide range of plant organs, revealing a high degree of heterogeneity in the substitution pattern of wall polymers such as the cross-linking glycan xyloglucan and the pectic polysaccharide homogalacturonan. The high sensitivity of MALDI-TOF allows the use of small amounts of samples, thus making it possible to investigate the wall structure of single cell types when material is collected by such methods as laser micro-dissection. As an example, the analysis of the xyloglucan structure in the leaf cell types outer epidermis layer, entire epidermis cell layer, palisade mesophyll cells, and vascular bundles were investigated. OLIMP is amenable to in situ wall analysis, where wall polymers are analyzed on unprepared plant tissue itself without first isolating cell walls. In addition, OLIMP enables analysis of wall polymers in Golgi-enriched fractions, the location of nascent matrix polysaccharide biosynthesis, enabling separation of the processes of wall biosynthesis versus post-deposition apoplastic metabolism. These new tools will make possible a semi-quantitative analysis of the cell wall at an unprecedented level.

BackgroundBiomass use for the production of bioethanol or platform chemicals requires efficient breakdown of biomass to fermentable monosaccharides. Lignocellulosic feedstocks often require physicochemical pretreatment before enzymatic hydrolysis can begin. The optimal pretreatment can be different for different feedstocks, and should not lead to biomass destruction or formation of toxic products.MethodsWe examined the influence of six mild sulfuric acid or water pretreatments at different temperatures on the enzymatic degradability of sugar-beet pulp (SBP).ResultsWe found that optimal pretreatment at 140°C of 15 minutes in water was able to solubilize 60% w/w of the total carbohydrates present, mainly pectins. More severe treatments led to the destruction of the solubilized sugars, and the subsequent production of the sugar-degradation products furfural, hydroxymethylfurfural, acetic acid and formic acid. The pretreated samples were successfully degraded enzymatically with an experimental cellulase preparation.ConclusionsIn this study, we found that pretreatment of SBP greatly facilitated the subsequent enzymatic degradation within economically feasible time ranges and enzyme levels. In addition, pretreatment of SBP can be useful to fractionate functional ingredients such as arabinans and pectins from cellulose. We found that the optimal combined severity factor to enhance the enzymatic degradation of SBP was between log R'0 = -2.0 and log R'0 = -1.5. The optimal pretreatment and enzyme treatment solubilized up to 80% of all sugars present in the SBP, including ≥90% of the cellulose.

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Na[Ag(CN)2], Mr = 182-90, monoclinic, C2/c, a = 6-572 (1), b = 3-710 (1), c = 17.346 (2)/~, fl = 92.05 (1) °, V = 422.66/~3, Z=4, Dx = 2.874 Mg m -3, A(Mo Kte) = 0.71073/~, /x = 4.527 mm-1, F(000) = 336. The structure was refined to R=0.072, wR=0.052 for 293 absorptioncorrected observed reflections. The Ag atoms of linear NC--Ag---CN groups are arranged in layers parallel to (001). The Na ions occupy octahedral holes between pseudohexagonal nitrogen layers with the sequence ABAB.Experimental. This very stable compound is easily obtained by reaction of NaCN with AgCN in aqueous suspension. All attempts, however, to grow good-quality single crystals failed up to now, so that only powder diffraction data have been recorded in the literature. We have succeeded in growing single crystals by slow recrystallization from a 1:1 ethanolwater mixture. Unfortunately most of these crystals were also of poor quality, mainly because of intergrowth and a high degree of disorder. After inspection of a large number of crystals by microscopy and film methods a clear crystal fragment (30 x 30 × 60 Ixm) could be isolated, which proved suitable for a structure determination. Gandolfi and Guinier patterns showed the fragment to be the same phase as the other crystals and the bulk material.For data collection, an Enraf-Nonius CAD-4 diffractometer was used (MoKa, A=0.71073A, graphite monochromator). Lattice parameters were refined from 20 values of 25 reflections in the range 4.8-36 °. Intensities measured for 2 _< 0___ 20°; oy-20-scan technique (scan width 0.85 ° + 0.34 ° tan0). Three standard reflections indicated a 2.2% loss of intensity during data collection. Mergin~ of the 1308 collected intensities [(sin0)max/A = 0.481 A; -5 _< h <_ + 5, -5 ___ k ___ + 5, -24 _< l ___ + 24] gave 293 unique reflections (Rin t = 0"031) with F> 3a(F), which were considered as observed and used for all calculations (program system SHELX76; Sheldrick, 1976).