Aims: Cyanobacteria have been used as sustainable bioresource producers for foods, feeds and other valuable natural products. However, selection of a new species (other than Arthrospira), with advantageous properties for alimentary purposes, continues to be a challenge due to potential toxicity and low biomass productivity. In this study, we report a valuable filamentous cyanobacterium isolated from Korea. Methods and Results: Morphological and phylogenetic analyses demonstrated that the isolate belongs to the genus Leptolyngbya, and consequently designated Leptolyngbya sp. KIOST-1. Interestingly, Leptolyngbya sp. KIOST-1 possessed numerous advantageous characteristics for biomass production, similar to Arthrospira. The isolate readily propagated in SOT medium with efficient biomass productivity, and its optimum growth was observed at 30 degrees C under alkaline and saline conditions. Moreover, more than half of the cellular components in Leptolyngbya sp. KIOST-1 were composed of protein, with approx. 40% of essential amino acids. Most importantly, no significant cytotoxicity was detected in the isolate. Conclusions: Leptolyngbya sp. KIOST-1 has a number of advantageous characteristics for alimentary purposes due to its efficient productivity, high protein content and lack of potential cytotoxicity. Significance and Impact of the Study: Leptolyngbya sp. KIOST-1 may be considered a potential candidate for industrial biomass production, similar to Arthrospira.