Chemical composition and biological origin of ‘dirty sea’ mucilages

Abstract

The carbohydrate composition of the extracellular exudates of the native algae cells floating in the Adriatic sea during the summer have been determined. These results were then compared with similar analyses performed on the excreted organic matter produced by in vitro cultures of Amphora coffeaeformis and Cylindrotheca fusiformis, both of which have been isolated in the past in the same areas of the Adriatic sea. Separation of the jelly-like polymeric components of the mucilages is described. The insoluble fraction presents a monomer distribution similar to that of C. fusiformis, while the unprecipitable fraction is similar to that of A. coffeaeformis. Native mucilages appear to be an intimate mixture of the extracellular exudates produced by the in vivo metabolism of the two diatoms.