Microbial polysaccharides are multifunctional and can be divided into intracellular polysaccharides, structural polysaccharides and extracellular polysaccharides or exopolysaccharides (EPS). Extracellular polymeric substances (EPS), produced by both prokaryotes (eubacteria and archaebacteria) and eukaryotes (phytoplankton, fungi, and algae), have been of topical research interest. Newer approaches are carried out today to replace the traditionally used plant gums by their bacterial counterparts. The bacterial exopolysaccharides represent a wide range of chemical structures, but have not yet acquired appreciable significance. Chemically, EPS are rich in high molecular weight polysaccharides (10 to 30 kDa) and have heteropolymeric composition. They have new-fangled applications due to the unique properties they possess. Owing to this, exopolysaccharides have found multifarious applications in the food, pharmaceutical and other industries. Hence, the present article converges on bacterial exopolysaccharides.

Planococcus maitriensis Anita I (NCBI GenBank Accession number EF467308) was tested for its biosurfactant/bioemulsifying efficacy. The crude extracellular polymeric substance (EPS) produced by this bacterium contained carbohydrate (12.06%), protein (24.44%), uronic acid (11%) and sulfate (3.03%). The oil spreading potential of this EPS was comparable to Triton X100 and Tween 80. This exopolymer emulsified xylene more efficiently as compared to few standard gums. It also formed stable emulsions (E (1,080)=100) with jatropha, paraffin and silicone oils. The cell free supernatant of this bacterium successfully reduced the surface tension (from 72 to 46.07 mN m(-1)). It also decreased interfacial tension of hexane and xylene. Based on the emulsifying and tensiometric properties, this bacterium or its exopolymer could be used for bioremediation, enhanced oil recovery and in cosmetics.

The present investigation involves the use of green marine macroalgae, U. pertusa, as a tool for bioassay of heavy metals (silver, arsenic, cadmium, cobalt, chromium, copper, iron, mercury, manganese, nickel, lead and zinc) prevalent in most industrial wastewaters. This is the first report of its kind wherein both, sporulation as well as spore release, is investigated synchronously. The EC 10 and EC 50 values obtained were also compared with toxicity norms of waste water quality criteria in Korea and global permissible limits. Based on variability it could be stated that the sporulation test was more reliable than the spore release test. The cosmopolitan presence of Ulva spp. makes the applicability of both these tests prominent as effective diagnostic tools for detecting pollution in metal polluted waters.

Pollutants have a dramatic ecological impact on aquatic environment and in particular the dwelling flora and fauna. This study focused on use of a new effortless approach to detect water pollution viz. Ulva growth bioassay. Several different water samples including a) wastewater obtained from a plating industry; b) stream water from five streams in Incheon viz. Gongchon, Jangsu, Hagik, Gulpo and Gyesan stream were investigated for their toxicity to the green marine macroalga, Ulva pertusa. Growth of U. pertusa showed concentration-dependent response to plating effluents, proving to be a suitable end point for estimating the wastewater toxicity. Comparison of the results obtained using conventional chemical assays and the Ulva bioassay coincided with each other in identifying the most polluted stream water out of the five streams tested.