ABSTRACT
Microbial polysaccharides are a class of water-soluble polymers that have grown to industrial importance over the past 40 years. These compounds are produced by different types of microorganisms and are recognized to assist microbial communities in their survival. These polymeric compounds, because of their novel and unique properties, are rapidly emerging as materials that can offer a wide range of applications in such diverse elds as food, pharmaceutical, and other industries.1-5 Over the last few decades, there has been an increasing interest in the isolation and identication of microbial extracellular polysaccharides to better understand their functional properties and compare them with those of traditional polysaccharides. This interest has also encouraged efforts to elucidate their composition and structure, evaluate their biosynthetic routes, identify applications of their molecular biology, determine their functionality, develop the technology necessary for their production, and identify potential uses in food, medicine, biotechnology, and other industries.1-6 This chapter discusses extracellular polysaccharides from marine microorganisms and their characteristics. Many related areas, such as biosynthetic pathways, polymer secretion, microbial biolms, genetic engineering, and chemical modications of polysaccharides, are not within the scope of this discussion and can be further studied elsewhere.1-6 In order to understand the production and properties of extracellular polysaccharides from marine microorganisms, it is pertinent to briey present a few examples of polysaccharides from some non-marine microorganisms that are important food additives, including dextran, xanthan, gellan, cellulose, bacterial alginate, and curdlan. This chapter, then, begins with a general discussion on extracellular polysaccharides from non-marine microorganisms before moving on to a discussion of marine polysaccharides and their potential applications.
