Liquefaction of Yallourn brown coal at low pressures and rapid heating rates

Liquefaction of Yallourn brown coal in solvents at high temperature for short contact times and low pressures has been studied. Very high asphaltene yields are achieved with hydrogen-donating solvents (hydrogenated Ashland pitch A240, hydrogenated anthracene oil, and hydrogenated pyrene). For hydrogenated pyrene, yields of almost 90% were obtained during reaction at 450°C for 10 min or at 510°C for 1 min. The average molecular weight of the asphaltene found was 270, with 40 wt% being accounted for by three-and four-ring polynuclear hydrocarbons. The effect of liquefaction temperature, time, and solvents on the asphaltene yield have been examined to clarify the properties required for the solvent under the present conditions used. The behaviour of the asphaltene during pyrolysis and hydrotreatment has also been studied. Some mechanistic aspects of high-temperature, short contact time liquefaction are discussed with regard to the reactivities of the brown coal and the solvents.     

Fate of coliphage in a wastewater treatment process

The fate of coliphage in a wastewater treatment plant in the central part of Japan was investigated from March to December 2001. A relative abundance of coliphage, 1000-10,000 PFU/ml determined with three different Escherichia coli strains, was detected in the influent. But, no remarkable seasonal change in the phage concentration in the influent was observed during the ten-month test period. Almost ten times higher coliphage concentration was detected by the F+ E. coli strain than by the other two F- strains. The RNA phage was more stable than the DNA phage against aerobic treatment using activated sludge. Most of the phages in the influent and primary settling tank were detected as suspended forms. Anaerobic-aerobic treatment enhanced adsorption of the phage by the solid particles. Almost no phage was detected in the effluent. Aerobic treatment using activated sludge and/or the addition of flocculants such as PAC was effective for the removal of coliphage, an index of enteric viral pollution.     

Structural Change of Potato Starch Granules by Ball-mill Treatment

Molecular change of potato starch granule by ball-mill treatment was investigated. Starch granule still retained its whole figure after 320h, treatment, but its surface changed extremely rough. Water absorption activity extremely increased by 10h treatment. Amylase susceptivity of starch increased according to treatment time. X-ray diffraction pattern lost its peak and enthalpy on DSC decreased 70% after 20h treatment. Iodine color reaction value decreased 30% and λ max shifted hypso-chromic 15nm in the both cases of debranched and non-debranched samples after 20h treatment, and this indicates amylose was also degraded by the treatment. However, the peak of amylose decreased 10% and the peak of amylopectin decreased 10% on each GPC of branched and non-debranched samples after 20h treatment. GPC (Toyopearl HW-65) of 320h treated sample shows only one peak, but its debranched sample shows similar pattern to that of non-treated sample on HPAEC. ¹³C-solid state NMR spectra suggest that total disruption frequency is fairly low after long this treatment.     

Bifidobacterial GH146 β-l-Arabinofuranosidase (Bll4HypBA1) as the Last Enzyme for the Complete Removal of Oligoarabinofuranosides from Hydroxyproline-Rich Glycoproteins

In plant cell walls, the hydroxyproline-rich glycoproteins (HRGPs) such as extensin contain oligoarabinofuranoside linked to a hydroxyproline (Hyp) residue. The mature arabinooligosaccharide was revealed to be a tetrasaccharide (α-l -Araf-(1→3)-β-l -Araf-(1→2)-β-l -Araf-(1→2)-β-l -Araf, l -Araf₄), whose linkages are targets of the bifidobacterial and Xanthomonas arabinooligosaccharide-degrading enzymes. The l -Araf₄ motif was cleaved by GH43 α-l -arabinofuranosidase (Arafase) and converted to an l -Araf₃-linked structure. The latter is then cleaved by GH121 β-l -arabinobiosidase (HypBA2), producing β-l -Araf-(1→2)-l -Ara (β-l -arabinobiose) and mono-β-l -Araf linked to the HRGP backbone. In bifidobacteria, the β-l -arabinobiose is then hydrolyzed by GH127 β-l -Arafase (Bll1HypBA1), a mechanistically unique cysteine glycosidase. We recently identified the distantly related homologue from Xanthomonas euvesicatoria as GH146 β-l -Arafase along with paralogues from Bifidobacterium longum, one of which, Bll4HypBA1 (BLLJ_0089), can degrade l -Araf₁-Hyp in a similar way to that of GH146. As the chemical synthesis of the extensin hydrophilic motif 1 a , which possesses three distinct linkages that connect four oligoAraf residues [Hyp(l -Araf_n) (n=4, 3, 1)], was achieved previously, we precisely monitored the step-wise enzymatic cleavage of 1 a in addition to that of potato lectin. The results unequivocally revealed that this enzyme specifically degrades the Hyp(l -Araf₁) motif.