ABSTRACT
The EPS-producing bacteria have been isolated from different zones of the marine environment, such as surface water, sediments, mangroves, hydrothermal vents, and deep sea (Poli et al. 2010, 2011). Many marine bacteria from genera Halomonas, Bacillus, Pseudomonas, Pseudoalteromonas, Marinobacter, Alteromonas, Alcanivorax,
17.1 Introduction ................................................................................................................................................................... 235 17.2 Functional diversity of EPSs ....................................................................................................................................... 236
17.2.1 Structural polysaccharides .............................................................................................................................. 236 17.2.2 Capsular polysaccharides ................................................................................................................................ 238 17.2.3 Biolm-associated polysaccharides................................................................................................................ 238
17.3 Biosynthesis and genetic regulation of EPSs ............................................................................................................ 241 17.4 Distribution of EPS-producing marine bacteria....................................................................................................... 242
17.4.1 Hydrothermal vents ......................................................................................................................................... 242 17.4.2 Mangroves ......................................................................................................................................................... 244 17.4.3 Hypersaline marine environment .................................................................................................................. 244 17.4.4 Cold marine environment ............................................................................................................................... 245 17.4.5 Sediments and surface water .......................................................................................................................... 245
17.5 Environmental applications ........................................................................................................................................ 246 17.5.1 Hydrocarbon remediation ............................................................................................................................... 246 17.5.2 Metal remediation............................................................................................................................................. 247 17.5.3 Biofouling control ............................................................................................................................................. 247
17.6 Summary ........................................................................................................................................................................ 248 Acknowledgments ................................................................................................................................................................. 248 References ................................................................................................................................................................................ 248
and Rhodococcus are known to produce EPS (Calvo et al. 2002; Bhaskar and Bhosle 2006; Iyer et al. 2006; Dash et al. 2014; Mangwani et al. 2014). EPSs from bacteria have a very prospective role in bioremediation of hydrocarbons and heavy metals in the marine environment. Chemically, EPSs from marine bacteria are polyionic and rich in uronic acid. Ionic nature assists in the binding with cations (metal cations), whereas uronic acid interfaces with hydrophobic organic compounds such as hydrocarbons (Iyer et al. 2006). A modest quantity of amino acids and peptides are also present in EPS, which confer amphiphilic properties to the EPS. EPSs have been reported to emulsify hydrocarbons, crude oil, and rened petroleum products (Abbasi and Amiri 2008; Abari et al. 2012). Apart from that, EPSs produced by some marine bacteria are also helpful in controlling biofouling (Kim et al. 2011). Bacterial EPSs serve diverse roles in the marine environment. It acts as a source of carbon, provides protection, helps in trace metal entrapment, cell immobilization, formation of mixed communities, and degradation of pollutants (Poli et al. 2010). This chapter illustrates the diverse aspects of bacterial EPS, their structural and functional diversity, genetic regulations, and environmental applications.
