Enzymatic hydrolysis of xylan in raw alkaline lignin by xylanase from Trichoderma reesei was studied. The optimal hydrolysis conditions were determined as follows:pH value 4.8,temperature 45 ℃,hydrolysis time 4 h.
The gross products are deproteined by trichloroacetic acid and twice enzymic hydrolysis. The purified product solution is then precipitated in succession with ethanol(42% and 80%) to get acidic mucopolysaccharide fractions Ⅰand Ⅱ,of which the contents of total sugar are 71.6% and 80.4% while the contents of protein are 1.52% and 1.38%,respectively.
The enzymatic hydrolysis of 6,4', 1" ,6"-tetrachloro-6,4', 1", 6"-tetradeoxy-raffinose (TCR)was discussed in detail. And the enzymatic synthesis of raffinose was studied briefly.
With the increasing of hydrolysis time, the average hydrodynamic radius ofhydrolyzed SPI aggregates deceased from 160nm to 110nm, the distribution ofhydrodynamic radius of SPI broadened, and the ζ-potential of SPI decreased from-24mv to about -37mv.
The complexation reaction between Al (Ⅲ) ion and α-glycerophosph oric acid and the hydrolysis of aluminum α-glycerophosphate were studied by means of pH-potentiometric titration at 23.0°±0.1° and ionic strength 0.10 (potassium nitrate).
The phenol hydroxyl groups of gallic acid were protected by benzylation which was cleaved subsequently by 10% palladised charcoal, and the four hydroxyl groups (1,2,4,6) of glucose shielded by isopropylation followed with acid hydrolysis.
On the basis of total acid hydrolysis, methylation analysis, periodate oxidation and NMR studies (1H and 13C) the structure of the repeating unit of the polysaccharide was assigned and indicated only α-(1→4) linked Glucan.
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The structural information of the glucan was achieved by chemical (hydrolysis, methylation, periodate oxidation) and spectroscopic (1H and 13C) analyses, indicated a repeating unit built up of (1→6)-linked D-glucose.
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Subsequent hydrolysis of the esters afforded the corresponding carboxylic acids (3a-l) (86-93%) and (5a-c) in high yield (80-93%).
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Glutaric dialdehyde was prepared by the addition-hydrolysis reaction of benzimidazolium salt with saturated dihalide as the di-Grignard reagent.
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Enzymatic hydrolysis of protein: Mechanism and kinetic model
This paper deals with the synthesis of 3-[o-dichloro (or monochloro-) acetamino-p-nitro-plenyl]-propanol (Ⅱ or Ⅱa),structurally varying from chloramphenicol on the one hand by shif-ting the dichloroacetamino group from the aliphatic side-chain to aromatic ring and replacing thesecondary hydroxyl group by hydrogen on the other,for the purpose of investigating the relationbetween biological action and chemical constitution of the antibiotic.The resulting compoundsshowed no inhibiting effect against E.coli,S.t...
Two new crystalline glucosides have been isolated from the Chinese drug Chiu-pi-ying, which is identified as Ilex spp. and popularly used for curing malaria fever in Kwangsi province. They are provisionally named ilexanin A and ilexanin B respectively. The ilexanin A has the emperical formula, C_(19)H_(28)O_(10), m.p. 194°[α]_D~(31)—24°, and a crystalline acetyl derivative, C_(19)H_(22)O_(10)(CH_3CO)_6, has been prepared. It contains two methoxy groups. When hydrolysed with 5% sulphuric acid, it gives amorp...
The recovery of phenols from the waste tar-water of low-temperature coal carbonization with butyl acetate has been investigated.97% of the total phenols is recovered by 4-stage countercurrent extraction of the tar-water with 15% by volume of butyl acetate.The extraction efficiency and the hydrolysis loss of the solvent are greatly effected by the pH value of the water.A pH around 7 is found to be particularly advantageous.The phenol content of recycle solvent should not exceed 1% in order to obtain ef...