Starch membranes polarization

Electron microscopy of radish radicle. Details of columella cells from 16 h-control seed (a) and seed treated with 1/14-diluted reverse osmosis fraction (b-d). (a) Columella cells in the control are distinctly polarized and contain large amyloplasts (arrows). Nucleus (N). (b) Columella cells in treated roots are not polarized and contain no amyloplasts. The numerous electron-transparent vesicles are swollen mitochondria (M). (c) Detail showing swollen mitochondria (M) and starch-less plastids (P). (d) High magnification of swollen mitochondria showing the two-membrane envelope (arrows). 

The hydrolysis of starch in a membrane reactor has been shown to suffer from disadvantageous formation of a concentrated gel layer at the membrane surface caused by the effect of concentration polarization and to some extent by the ageing of the starch solution. It was demonstrated that glucoamylase, from Aspergillus niger, reduces the formation of a gel layer and gives higher and more-stable performances of the membrane reactor. 

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