Cyanobacterial emulsifiers
Halophilic cyanobacteria produce large amounts of exopolysaccharides (EPS), which can be relevant to oil recovery by decreasing its surface tension and increasing its solubility and mobility. EPS, when gelated under alkaline conditions, was employed to remove dyes from textile effluent. The halophilic cyanobacterium Aphanocapsa halophytica was used for the production of EPS and its yield was increased to tenfold by immobilizing the cells on light-diffusing optical fibres (Matsunaga et al. 1996). The cyanobacterium Cyanothece sp. ATCC 51142 had a maximum EPS production at 4·5% (w/v) NaCl and pH 7 (Shah et al. 1999). Other EPS-producing cyanobacteria are the halotolerant Anabaena sp. ATCC 33047 (Moreno et al. 1998) and Synechococcus sp. (Matsunaga et al. 1991). It should be pointed out that it is necessary in future research to investigate the potential of additional cyanobacteria in EPS production.