Assessment of Synechococcus elongatus PCC 7942 as an option for sustainable wastewater treatment

Abstract

Industrial wastewaters are recognized as a valuable resource, however their disposal without proper treatment can result in environmental deterioration. The associated environmental/operational cost of wastewater treatment necessitates upgrade of applied processes towards the goals of sustainability and mitigation of climate change. The implementation of cyanobacteria-based processes can contribute to these goals via resources recovery, production of high-value products, carbon fixation and green-energy production. The present study evaluates the cyanobacterium Synechococcus elongatus PCC 7942 (S7942) as a biological component for novel and sustainable alternatives to typical biological nutrient removal processes. Valuable results regarding cultivation temperature boundaries, applied disinfection techniques and analytical methods, as well as regarding relations between parameters expressing S7942 biomass concentration are presented. The results show that at typical industrial wastewater temperatures, S7942 efficiently grew and removed nitrates from treated snack-industry's wastewater. Moreover, in cultures with treated and relatively saline dairy wastewater, its growth rate slightly decreased, but nevertheless nitrates removal rate remained efficiently high. A comparison between typical denitrification processes and the proposed nutrient removal process indicated that a S7942-based system may constitute an alternative or a supplementary to denitrification process. Thus, Synechococcus elongatus PCC 7942 proved to be a potent candidate towards sustainable industrial wastewater treatment applications.

Pleiotropic effects of PipX, PipY, or RelQ overexpression on growth, cell size, photosynthesis, and polyphosphate accumulation in the cyanobacterium Synechococcus elongatus PCC7942

“…These strategies, most of them carried out in E. coli , dealt with increasing the levels of polyP kinase (PPK), encapsulating it, or increasing phosphate transport ( Kato et al, 1993 ; Keasling et al, 1998 ; Liang et al, 2017 ). However, massive polyP accumulation in a cyanobacterium is of greatest biotechnological interest and, in this context, S. elongatus has been shown to be an option for sustainable wastewater treatment ( Samiotis et al, 2021 ).…”

Co‐production of bioethanol and commercially important exopolysaccharides from the marine cyanobacterium Synechococcus elongatus BDU 10144 in a novel low‐cost seawater‐fertilizer‐based medium

“…A concentration range of 10 to 100 μmol m −2 s −1 was also shown to be apposite for the growth of M. aeruginosa 63 . Recently, Samiotis et al 64 reported that S. elongatus 7942 productivity was significantly reduced at light intensities between 5 and 30 μmol m −2 s −1 , and temperatures between 30 and 32°C were optimal for S. elongatus 7942 growth, demonstrating the critical role of temperature and light in cyanobacterial cultivation.…”

A Cryo-CMOS PLL for Quantum Computing Applications

“…The average C assimilation rate was 35.03 mg/(g-MLVSS•d) during the last 12 days (Table 2). To estimate the contribution of phototrophs to C fixation in the algal-bacterial AGS, an empirically stoichiometric formula of CH 1.78 O 0.36 N 0.12 P 0.01 (Boelee et al, 2014) for phototrophs and a ratio of 56.31 mg-MLVSS/mg-Chl-a (Samiotis et al, 2021) were used. As shown in Table 2, the contribution of phototrophic organisms to C sequestration was about 23.28 mg/(g-MLVSS•d), with a CO 2 fixation capacity of 85.36 mg-CO 2 /(g-MLVSS•d), which accounted for about 66% of total C assimilation by the algal-bacterial AGS.…”