A STUDY OF A POLYSULFONE MEMBRANE FOR USE IN AN IN-SITU TUNABLE MICRODIALYSIS PROBE DURING MONITORING OF STARCH ENZYMATIC HYDROLYSATES

We report a study made on a 5 kDa molecular weight cut-off (MWCO) poly sulfone membrane (SPS 4005) for use in microdialysis sampling of starc h enzymatic hydrolysates on-line coupled to column liquid chromatograp hy with integrated pulsed electrochemical detection. Membrane characte ristics were evaluated by examining both the membrane and membrane sup port layer using a scanning electron microscope (SEM). This study was made so as to elucidate the mechanism or mode by which a membrane expo sed to different bioprocess conditions is either fouled or destroyed. The correlation of extraction fraction data with SEM was a confirmator y test for the observed change in the membrane characteristics. Examin ations were made after keeping the membrane in pure water for 5, 10 an d 30 min at room temperature or after perfusing the membrane with pure water continuously at room temperature, 60 and 90 degrees C for 24 h. Extraction fractions were evaluated at these temperatures to see appl icability of the SPS 4005 membrane to high temperature bioprocesses. S canning electron microscopy studies were also made on membranes used f or sampling and sample clean-up during on-line monitoring of the hydro lysis of soluble starch (according to Zulkowsky) for 32 h, and the hyd rolysis of wheat starch at room temperature, 60 and 90 degrees C for 6 h. Non-specific/directed protein-membrane interactions were evaluated by sampling maltoheptaose with a microdialysis probe fitted with a 10 mm SPS 4005 membrane, before and after treatment with an enzyme solut ion of Termamyl (endo-1,4-alpha-D-glucan glucanohydrolase EC 3.2.1.78) .