Viscometry of Curdlan, a Linear (1→3)-β-D-Glucan, in DMSO or Alkaline Solutions

A simple method to obtain the molecular weight of curdlan was found by viscometry in its alkaline or DMSO solution. DMSO was found to be the most appropriate solvent for measuring Mv of curdlan. Based on two Sakurada-Houvink equations, [η]=KM(a), which have been obtained so far in alkaline solutions, two sets of parameters of the equation in the DMSO solution, that is, K=3.5×10(-4), a=0.65 and K=1.6×10(-4), a=0.74 were introduced, respectively. Both parameter sets seemed to serve practically to measure the molecular weight of curdlan. In addition, using the equation obtained with several NaOH concentrations, the previous speculation that curdlan conformation changes from a rigid rod to random coil with alkaline concentration was confirmed.