ABSTRACT
Although various plant and seaweed gums have been used for years to alter the rheological properties of aqueous systems, there are many industrial applications for gums with improved or different functionality. Since microbial gums are produced under controlled conditions, problems of plant and seaweed gums with climatic conditions, collection, supply, and quality can be avoided. There are numerous classes of polysaccharides from microbial sources. Some polysaccharides whose normal commercial sources are plants, animals, or seaweed can be found in various microbial sources. Although microbial polysaccharides can be grouped in many ways, it is convenient to classify them according to the charge they carry, i.e., acidic, basic, or neutral. Acidic polysaccharides, deriving their charge from either uronic acids or acidic acyl substituents, appear to be more common than neutral polysaccharides. Microbes that produce exocellular polysaccharides are nearly ubiquitous. They are found in such places as effluents from paper and sugar mills, soil, and plants.
