Whole Genome Sequence and Experimental Proteome of Candidatus 'Phormidium Alkaliphilum', an Abundant and Widespread Cyanobacterium With Applications in Biotechnology

Cyanobacteria encompass a diverse group of photoautotrophic bacteria with important roles in nature and biotechnology. Here we introduce Candidatus “Phormidium alkaliphilum”, an abundant member of alkaline soda lake microbial communities across the globe. Multiple, independent studies have reported successful colonization of photobioreactors for biotechnology applications by Ca. “P. alkaliphilum” and closely related cyanobacteria. The complete, circular whole genome sequence of Ca. “P. alkaliphilum” was obtained using combined Nanopore and Illumina sequencing of a consortium abundant in Ca. “P. alkaliphilum”. Strain heterogeneity of the Ca. “P. alkaliphilum” population was shown to contribute to photobioreactor robustness under different operational conditions. Comparative genomics of closely related Phormidium species showed that adaption to high pH and alkalinity could not be attributed to specific genes. Proteomics showed high pH (11.2) provoked only minimal changes in gene expression in Ca. “P. alkaliphilum”, compared to control cultures at pH 9. Diversity of photosystem antennae proteins, a high affinity terminal oxidase and ecophysiological flexibility contributed to success of Ca. “P. alkaliphilum” in photobioreactors and biotechnology, compared to other soda lake cyanobacteria.