Effects of growth conditions on exopolysaccharide production by Cyanospira capsulata

✍ Scribed by R. De Philippis; C. Sili; G. Tassinato; M. Vincenzini; R. Materassi

• Publisher: Elsevier Science
• Year: 1991
• Tongue: English
• Weight: 362 KB
• Volume: 38
• Category: Article
• ISSN: 0960-8524
• DOI: 10.1016/0960-8524(91)90138-a

✦ Synopsis

Batch cultures of Cyanospira capsulata, a hetero-O'stous cyanobacterium possessing a thick polysaccharidic capsule, were characterized /)3, increasing viscosity owing to the continuous release Of" a soluble polysaccharide (EPS) into the culture medium. Both capsulated trichomes and solubili::ed El'5" contributed to the flow properties of whole cultures. A typical pseudoplastic behaviour, the more marked the more aged were the cultures, was evidenced.

The production of EPS was investigated under d(fferenl growth conditions by changing some nutritional and physical parameters known to affect the synthesis of exopolysaccharides in algae and c3'anobacteria. Among the factors tested (Ca -~÷, Mg :+ or PO~-deficiencies, salinity and pH) only Mg 2+ shortage caused a significant enhancement of the Et'5 production. Under continuous illumination in open ponds, the EPS productivity of batch cultures on standard mineral medium was about 5.8 g m -: day-t whereas under Mg 2+ deficiency values off about 6"8 gm-: day -I were obtained, with a c, msequent increase o[ the cultures 'viscosio,.