Potential new genera of cyanobacterial strains isolated from thermal springs of western Sichuan, China

Cyanobacteria have shown great potential for energy and environmental applications. Cyanobacterial resources, however, are still largely unexplored. Here, forty-nine out of one hundred thirty-two cyanobacterial isolates recovered from thermal springs of western Sichuan, China, were characterized. The phylogenetic analysis of 16S rRNA gene sequences categorized the isolates into three genera, Thermosynechococcus (63.3%), Leptolyngbya (34.7%) and Stanieria (2.0%). Based on sequence similarity, five phylotypes were identified as either putative new species of genus Leptolyngbya or possibly completely new genera. Temperature test showed that all isolates were thermotolerant and twenty-five isolates were capable of growth at temperature of 60 °C, suggesting that these isolates may have strong biotechnological potential. Additionally, three isolates exhibited NaHCO3 tolerance as high as 1 M, indicating that the isolates are promising candidates for bicarbonate-based cyanobacteria production system. Overall, this research laid solid basis for taxonomy and future exploration of extremophilic cyanobacteria for biotechnological and environmental applications.