Preservation methods of Tolypothrix tenuis for use as a cyanobacterial fertilizer

摘要

The suitability of the cyanobacterium Tolypothrix tenuis as a potential biofertilizer was evaluated by measuring cell viability in stored samples preserved by various methods, including freezing at ?20°C, freeze-drying, desiccation as flakes and immobilization in alginate beads. The viability recovery and the retained viability index (RVI10) were used as indicators of cell survival after 3 and 15 months storage. The highest recovery level (85%) was obtained by freeze-drying using skimmed milk as the resuspension solution for long-term storage. Dried alginate beads showed a better cell survival (RVI10 0.25) than air-dried flakes (RVI10 ?0.63) after 15 months storage. However, desiccated flakes previously treated with Ca2+ and Mg2+ ions improved cell survival capacity at the longest period assayed (RVI10 0.08), extending cell viability by 9 months compared to dried-powder material.