Applied Microbiology and Biotechnology

, Volume 70, Issue 1, pp 123–129

Biosynthesis of radiolabeled cellodextrins by the Clostridium thermocellum cellobiose and cellodextrin phosphorylases for measurement of intracellular sugars


DOI: 10.1007/s00253-005-0278-1

Cite this article as:
Zhang, Y.H.P. & Lynd, L.R. Appl Microbiol Biotechnol (2006) 70: 123. doi:10.1007/s00253-005-0278-1


The Clostridium thermocellum cellobiose and cellodextrin phosphorylases (glucosyl transferases) in the cell extract were used to synthesize radiolabeled cellodextrins with a degree of polymerization (DP=2–6) from nonradioactive glucose-1-phosphate and radioactive glucose. Chain lengths of synthesized cellodextrin were controlled by the absence or presence of dithiothreitol and by reaction conditions. All cellodextrins have the sole radioactive glucose unit located at the reducing ends. Mixed cellodextrins (G2–G6) were separated efficiently by size-exclusion chromatography or less efficiently by thin-layer chromatography. A new rapid sampling device was developed using disposable syringes containing an ultracold methanol-quenching buffer. It was simple, less costly, and especially convenient for anaerobic fermentation. After an impulse feed of radiolabeled cellobiose, the intracellular sugar levels were measured after a series of operations—sampling, extracting, concentrating, separating, and reading. Results showed that the largest amount of radioactivity was cellobiose with lesser amounts of glucose, cellotriose, and cellotetraose, and an average DP of intracellular cellodextrins was ca. 2.

Copyright information

© Springer-Verlag 2006

Authors and Affiliations

  1. 1.Biological Systems Engineering DepartmentVirginia Polytechnic Institute and State UniversityBlacksburgUSA
  2. 2.Thayer School of Engineering, 8000 Cummings HallDartmouth CollegeHanoverUSA

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