Post-storage viability and metabolic stability of immobilized cyanobacteria
Choudhary, Kaushal K.
The exploitation of cyanobacteria for bioactive compounds requires uniformly applicable techniques that can maintain wild type characteristics of the organisms during storage. In this study, two heterocystous cyanobacteria viz. Rivularia aquatica and Gloeotrichia echinulata were entrapped in sodium alginate and stored at 28, 4 and −20°C for one year to test the suitability of immobilization technique for storage. The pre and post storage analysis of chlorophyll a retention (viability index) by the beads of different origin revealed the maximum viability of 92 and 91% for the beads stored at 4°C followed by 71 and 73% for 28°C and 47 and 49% for −20°C during storage for R. aquatica and G. echinulata, respectively. Moreover, growth profile of stored beads in the nutrient medium showed maximum accumulation of cells inside beads and release of cells into the nutrient medium with beads stored at 4°C followed by 28 and −20°C. The findings of close relatedness between standard culture and cells escaped from beads stored at 4°C for Acetylene Reduction Assay indicated stability in wild character during storage. In conclusion, preservation of cyanobacteria at 4°C in immobilized state was most effective with respect to cost, ease of dissemination, reduced contamination risk with optimal viability and biochemical stability.