The First Report to Evaluate Safety of Cyanobacterium Leptolyngbya sp. KIOST-1 for Use as a Food Ingredient: Oral Acute Toxicity and Genotoxicity Study

Abstract

Leptolyngbya sp. KIOST-1 (LK1) is a newly isolated cyanobacterium that shows no obvious cytotoxicity and contains high protein content for both human and animal diets. However, only limited information is available on its toxic effects. The purpose of this study was to validate the safety of LK1 powder. Following Organisation for Economic Co-operation and Development (OECD) guidelines, a single-dose oral toxicity test in Sprague Dawley rats was performed. Genotoxicity was assessed using a bacterial reverse mutation test with Salmonella typhimurium (strains TA98, TA100, TA1535, and TA1537) and Escherichia coli WP2 uvrA , an in vitro mammalian chromosome aberration test using Chinese hamster lung cells, and an in vivo mammalian erythrocyte micronucleus test using Hsd:ICR (CD-1) SPF mouse bone marrow. After LK1 administration (2,500 mg/kg), there were no LK1-related body weight changes or necropsy findings. The reverse mutation test showed no increased reverse mutation upon exposure to 5,000 μg/plate of the LK1 powder, the maximum tested amount. The chromosome aberration test and micronucleus assay demonstrated no chromosomal abnormalities and genotoxicity, respectively, in the presence of the LK1 powder. The absence of physiological findings and genetic abnormalities suggests that LK1 powder is appropriate as a candidate biomass to be used as a safe food ingredient.

Optimization of Industrial-Scale Cultivation Conditions to Enhance the Nutritional Composition of Nontoxic Cyanobacterium Leptolyngbya sp. KIOST-1

“…This strain demonstrated biomass productivity, a high protein content, and an amino acid composition comparable to A. maxima, with no observed cytotoxicity [12]. Moreover, subsequent research identified no putative cyanotoxin genes, and the dried biomass did not exhibit acute toxicity in experimental animals [13,14]. These results suggest that Leptolyngbya sp.…”

“…Previous studies have reported that Leptolyngbya sp. KIOST-1 has a high protein content and no cytotoxicity, cyanotoxin-related genes, or acute toxicity, suggesting that it may be a potential protein source candidate [12][13][14]. In this study, we attempted to determine the fundamental physiological characteristics of this species necessary for its cultivation to produce biomass.…”