SCLEROGLUCAN

Cultures of filamentous fungi that secrete significant amounts of exop olysaccharides are among the most difficult of fermentation fluids, pr esenting difficulties in the areas of aeration, agitation, mixing, and control that may in turn impact the physiology of the microorganism i n an undesirable manner. The fungus Sclerotium glucanicum, which produ ces a potentially useful exopolysaccharide known as scleroglucan, illu strates many such difficulties. This review discusses in detail the ra nge of physiological studies on the producing microorganism itself, in cluding those concerning formation of ''undesirable'' byproducts, prin cipally oxalate, but also, under certain conditions, other TCA cycle a cids. In addition, the bioreactor technology in use for production of this type of biopolymer is discussed in relation to the difficulties s uch fluid types present. The potential of pneumatically agitated react ors for such production is evaluated, and the lack of fundamental stud ies on such reactors and on the hydrodynamics and mixing behavior of s uch complex fluids is pointed out.