ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 21 (1979), S. 1031-1042 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Chemical and physical treatments of cotton cellulose have been studied in order to elucidate the relationship between the degree of crystallinity of cellulose and the susceptibility of cellulose to cellulase. Cotton cellulose powder was treated with the following solvents: 60% H2SO4, Cadoxen, and DMSO-p -formaldehyde. The dissolved celluloses were recovered at high yield of over 97% by addition of nine volumes of cold acetone. X-ray diffraction for measurements of relative crystallinity showed that the crystalline structure of cellulose declined in quantity and perfection by the dissolving treatment and changed to an amorphous form that is highly susceptible to enzymatic hydrolysis. These reprecipitated celluloses were hydrolyzed almost completely within 48 hr by Aspergillus niger cellulase containing mainly 1,4-β-glucan glucanohydrolase (EC 3.2.1.4), without action of 1,4-β-glucan cellobiohydrolase (EC 3.2.1. 91). On the other hand, cryo-milled cellulose (below 250 mesh) still had a crystalline structure, was resistant to cellulase, and gave a low percentage of saccharification. These results indicate that in pure cellulose there are good correlations between x-ray diffractograms and susceptibility to microbial cellulase.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Fresenius' Zeitschrift für analytische Chemie 286 (1977), S. 212-213 
    ISSN: 1618-2650
    Keywords: Best. von Phosphat ; Elektroden, ionenselektive ; bleiselektive Elektrode
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Summary A lead ion-sensitive electrode responds to phosphate ion, and is successfully used for the determination of the ion in the concentration range of 10−5–10−1 M at a pH of 7–9 in the presence of 0.1 M sodium perchlorate and 5×10−2 M ammonium sulphate-ammonium hydroxide as ionic strength adjuster and pH buffer, respectively. The slope of the calibration curves is about −19 mV per decade of the concentration. The response reaches equilibrium within several min after immersing the electrode in the phosphate solution. Common anions, as F−, Cl−, Br−, NO 3 − , NO 2 − and HCO 3 s- , have little effect on the determination of phosphate ion, but OH−, HAsO 4 2− and I− affect it.
    Notes: Zusammenfassung Die Phosphatbestimmung kann im Bereich 10−5 bis 10−1 M bei pH 7–9 in Gegenwart von 0,1 M Natriumperchlorat und 5×10−2 M Ammoniumsulfat/ Ammoniumhydroxid zur Einstellung der Ionenstärke und als Puffer durchgeführt werden. Die Neigung der Eichkurve beträgt etwa −19 mV je Zehnerpotenz der Phosphatkonzentration. Wenige Minuten nach Eintauchen der Elektrode wird eine konstante Anzeige erreicht. Übliche Ionen, wie F−, Cl−, Br−, NO 3 − , NO 2 − und HCO 3 − , haben nur einen geringen Einfluß auf die Bestimmung, während OH−, HAsO 4 2− und J− stören.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...