Production of cyclodextrin glycosyltransferase by batch and chemostat culture of Bacillus macerans in chemically defined medium

Colorimetric determination of beta-cyclodextrin: two assay modifications based on molecular complexation of phenolphtalein

The decolorization of phenolphtalein upon complexation to cyclodextrins was studied to measure beta-cyclodextrin concentrations. Several factors possibly affecting the self-life of the dye were tested. By making the assays in 0.1 M NaCO3 solution beta-cyclodextrin concentrations down to 6 microM (SNR = 2) could be determined while the practical assay range reached up to 0.06 mM. In this form the method was unaffected by acyclic oligosaccharides and directly applicable to cyclodextrin assays in complex starch hydrolyzates. The method was further modified to be used in a flow-injection analyzator and the results were comparable to those obtained by HPLC analyses after prepurification of the samples.

The production of alpha-amylase in batch and chemostat culture by Bacillus stearothermophilus

The production of alpha-amylase (alpha-1,4-glucan 4-glucanohydrolase; EC 3.2.1.1) by a strain of Bacillus stearothermophilus isolated from leaf litter was investigated in a tryptone-maltose medium at 55 degrees C in batch and chemostat culture. Amylase production was growth-limited and restricted to the exponential phase in batch culture. The enzyme yield was reduced by 40% when the culture pH was maintained at pH 7.2. Amylase production in chemostat culture was influenced by the growth rate throughout the dilution rate range used.