Continuous cultivation of Arthrospira platensis for phycocyanin production in large-scale outdoor raceway ponds using microfiltered culture medium.

• Microfiltration could enhance phycocyanin production of Arthrospira platensis. • Microbiological contaminants were identified as bacteria and microzooplanktons. • The detected microbes could grew under salt-alkaline stress conditions. • Strategies for alleviating microalgal contamination were developed. In the present study, the effect of filtrating algal culture medium for reuse by using microfiltration membranes on microalgal growth, microbiological contamination, and phycocyanin production of Arthrospira platensis was investigated. Results showed that microfiltered culture medium affected microalgal growth, microbiological contamination, and phycocyanin production of A. platensis significantly. Microfiltered culture medium could enhance biomass production, photosynthesis, and phycocyanin accumulation and decrease microbiological contamination during continuous cultivation of A. platensis compared to the control. The profile of microbial communities, which contained the 10 phyla of microorganisms including bacteria and microzooplanktons, was identified for the first time for industrial algae systems of A. platensis with extreme conditions (salt-alkaline stress conditions). The application of the established strategy can enhance phycocyanin production of A. platensis while mitigating microbiological contamination. [ABSTRACT FROM AUTHOR]