Selection and ultrastructure and RAPD analysis of a new Spirulina platensis strain with high-efficiency dehydration performance

Abstract:

[Objective] Breeding a new Spirulina strain with high-efficiency dehydration performance, and effectively reducing the energy consumption of dry powder production. [Methods] The spheroplasts of Spirulina platensis strain ZJU0115 that is widely used in large-scale cultivation, were prepared by tissue homogenate breaking and centrifugal sedimentation. They were treated by 0.6% EMS for 30 min and 2.4 kGy ⁶⁰Co gamma rays, and then screened by Zarrouk's medium containing 0.02% xanthan gum, cultured by the single filament separating, detected of water-holding rate in algae sludge and extracellular polysaccharide (EPS) content in filtrate. [Results] A mutant named ZJU0115(HD) was obtained. The yield and contents of protein and polysaccharide in ZJU0115(HD) were similar to that in ZJU0115, but the sludge water-holding rate and EPS content of ZJU0115(HD) decreased by 5.9% and 29.7% respectively. Ultrastructure analysis showed that the filament surface of ZJU0115(HD) was smoother and had fewer milky-white adhesives considered acidic polysaccharides than that of ZJU0115. And the polyphosphate granules in ZJU0115(HD) cells were significantly smaller and more dispersed. Moreover, RAPD (randomly amplified polymorphic DNA) analysis indicated that the amplifcation bands of primers S₉₀ revealed significant polymorphisms between ZJU0115(HD) and ZJU0115. [Conclusion] ZJU0115(HD) has good production traits and stable high-efficiency dehydration performance in industrial cultivation. In particular, nearly 50% of the energy consumption of its sludge drying could be saved. The new strain will help promote the current Spirulina industry to a new stage of high efficiency, energy saving, green and environmental protection.