INTERACTION OF TRANSPORT RESISTANCES WITH BIOCHEMICAL REACTION IN PACKED-BED SOLID-STATE FERMENTORS - EFFECT OF TEMPERATURE-GRADIENTS

In solid-state fermentation, the interaction of transport phenomena wi th biochemical reactions has a consider able effect on the productivit y of the bioreactor. Previous work on solid-state fermentation in tray fermentors in our laboratory indicated that heat transfer resistance results in steep temperature gradients within the solid substrate bed, which in turn adversely affect the biochemical reaction and enzyme ac tivity. This problem of heat accumulation during the course of ferment ation has been alleviated to a considerable extent using a packed-colu mn bioreactor with forced aeration in the present work. Experimental s tudies were conducted in a packed-column bioreactor utilizing wheat br an a substrate and the fungus Aspergillus niger CFTRI 1105 for the pro duction of the enzyme amyloglucosidase. The enzyme activities were est imated and temperatures were recorded at different bed heights, for di fferent air flow rates during the course of fermentation. The results indicated that the temperature gradients caused by heat transfer resis tances were reduced considerably with corresponding increases in enzym e activity.