PT  - JOURNAL ARTICLE
AU  - Travis C. Korosh
AU  - Andrew Dutcher
AU  - Brian F. Pfleger
AU  - Katherine D. McMahon
TI  - Cyanobacterial Growth on Municipal Wastewater Requires Low Temperatures
AID  - 10.1101/161166
DP  - 2017 Jan 01
TA  - bioRxiv
PG  - 161166
4099  - http://biorxiv.org/content/early/2017/07/08/161166.short
4100  - http://biorxiv.org/content/early/2017/07/08/161166.full
AB  - Side-streams in wastewater treatment plants can serve as concentrated sources of nutrients (i.e. nitrogen and phosphorus) to support the growth of photosynthetic organisms that ultimately serve as feedstock for production of fuels and chemicals. However, other chemical characteristics of these streams may inhibit growth in unanticipated ways. Here, we evaluated the use of liquid recovered from municipal anaerobic digesters via gravity belt filtration as a nutrient source for growing the cyanobacterium Synechococcus sp. strain PCC 7002. The gravity belt filtrate (GBF) contained high levels of complex dissolved organic matter (DOM), which seemed to negatively influence cells. We investigated the impact of GBF on physiological parameters such as growth rate, membrane integrity, membrane composition, photosystem composition, and oxygen evolution from photosystem II. At 37°C, we observed an inverse correlation between GBF concentration and membrane integrity. Radical production was also detected upon exposure to GBF at 37°C. However, at 27°C the dose dependent relationship between GBF concentration and lack of membrane integrity was abolished. Immediate resuspension of strains in high doses of GBF showed markedly reduced oxygen evolution rates relative to the control. Together, this suggests that one mechanism responsible for GBF toxicity to Synechococcus is the interruption of photosynthetic electron flow and subsequent phenomena. We hypothesize this is likely due to the presence of a phenolic compounds within the DOM.