Molecular diversity of bacteria in commercially available "Spirulina" food supplements

Elisabeth Vardaka; Konstantinos A Kormas; Matina Katsiapi; Savvas Genitsaris; Maria Moustaka-Gouni

doi:10.7717/peerj.1610

Molecular diversity of bacteria in commercially available "Spirulina" food supplements

PeerJ. 2016 Jan 21:4:e1610. doi: 10.7717/peerj.1610. eCollection 2016.

Authors

Elisabeth Vardaka¹, Konstantinos A Kormas², Matina Katsiapi³, Savvas Genitsaris⁴, Maria Moustaka-Gouni⁴

Affiliations

¹ Department of Nutrition and Dietetics, Alexander Technological Educational Institute of Thessaloniki , Thessaloniki , Greece.
² Department of Ichthyology and Aquatic Environment, University of Thessaly , Volos , Greece.
³ Department of Nutrition and Dietetics, Alexander Technological Educational Institute of Thessaloniki, Thessaloniki, Greece; School of Biology, Aristotle University of Thessaloniki, Thessaloniki, Greece.
⁴ School of Biology, Aristotle University of Thessaloniki , Thessaloniki , Greece.

Abstract

The cyanobacterium Arthrospira is among the most well-known food supplements worldwide known as "Spirulina." While it is a widely recognized health-promoting natural product, there are no reports on the molecular diversity of commercially available brands of "Spirulina" supplements and the occurrence of other cyanobacterial and heterotrophic bacterial microorganisms in these products. In this study, 454-pyrosequencing analysis of the total bacterial occurrence in 31 brands of "Spirulina" dietary supplements from the Greek market was applied for the first time. In all samples, operational taxonomic units (OTUs) of Arthrospira platensis were the predominant cyanobacteria. Some products contained additional cyanobacterial OTUs including a few known potentially toxic taxa. Moreover, 469 OTUs were detected in all 31 products collectively, with most of them being related to the Proteobacteria, Firmicutes, Bacteroidetes, Actinobacteria and Verrucomicrobia. All samples included heterotrophic bacterial OTUs, ranging from 9-157 per product. Among the most common OTUs were ones closely related to taxa known for causing health issues (i.e., Pseudomonas, Flavobacterium, Vibrio, Aeromonas, Clostridium, Bacillus, Fusobacterium, Enterococcus). The observed high cyanobacterial and heterotrophic bacterial OTUs richness in the final product is a point for further research on the growth and processing of Arthrospira biomass for commercial purposes.

Keywords: Arthrospira; Bacteria; Cyanobacteria; Food supplements; Pyrosequencing; Spirulina.

Grants and funding

This project was implemented through the Operational Program “Education and Lifelong Learning” and is co-financed by the European Union (European Social Fund) and Greek National Funds (National Strategic Reference Framework: Archimides III). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.