高沥水性钝顶螺旋藻新品系的选育及超微结构与RAPD分析

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

摘要:

[目的]选育高沥水性的螺旋藻新品系，显著降低藻粉生产中干燥的能耗。[方法]以用于工厂化培植的钝顶螺旋藻ZJU0115为出发品系，用组织匀浆-离心沉降法制得其原生质球，并先以0.6% EMS处理30min再用2.4 kGy的⁶⁰Co γ射线辐照，经含0.02%黄原胶（xanthan gum）的Zarrouk’s培养液筛选、藻丝单体分离培养、藻泥持水率和胞外多糖（EPS）等检测及生产培植试验。[结果]获得了一株产量、蛋白质和多糖含量与ZJU0115相当，而藻泥持水率和EPS含量分别下降5.9%和29.7%的突变体，命名为ZJU0115（HD）。超微结构与随机扩增多态性DNA标记（random amplified polymorphic DNA，RAPD）分析结果显示，与其亲本ZJU0115相比，ZJU0115（HD）藻丝表面更光滑，可能为酸性多糖的乳白状粘附物也更少；ZJU0115（HD）细胞内的多磷酸盐颗粒显著变小且呈弥散状；基因组DNA在随机引物S90的扩增产物中显示出多态性差异。[结论]ZJU0115（HD）在工厂化培植中生产性状好、高沥水性能稳定，藻泥的干燥能耗降低了近50%，它的育成与应用，有助于推进当前螺旋藻产业迈向高效、节能、绿色、环保发展的新阶段。

关键词:钝顶螺旋藻;高沥水性;突变体;育种;超微结构;随机扩增多态性DNA标记

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.

Key words:Spirulina platensis;high-efficiency dehydration performance;mutant;breeding;ultrastructure;RAPD (randomly amplified polymorphic DNA)