Evolutionary Relationships Between Low Potential Ferredoxin and Flavodoxin Electron Carriers

Campbell, Ian; Bennett, George N.; Silberg, Jonathan J.

doi:10.3389/fenrg.2019.00079

Cited by 46 publications

(64 citation statements)

References 103 publications

(158 reference statements)

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“…Oedegonium, one of the principle species in these experiments, has high productivities [59] and is composed of a high proportion of carbon [60]. This rich organic composition improves potential for conversion of the algae into biogas using anaerobic biodigestion, particularly if mixed with sewage solids [61]. The economic feasibility of filamentous wastewater treatment systems is greatly improved when the biomass can be effectively converted to energy rich biofuels [17].…”

Section: Discussionmentioning

confidence: 99%

Carbon limitation in hypereutrophic, periphytic algal wastewater treatment systems

Furnish

Keller

2020

PLoS ONE

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Global eutrophication degrades water quality in freshwater ecosystems and limits the availability of freshwater for human consumption. While current wastewater treatment facilities (WWTF) remove pathogens and pollutants, many US WWTF continue to discharge nutrients that contribute to eutrophication. Traditional nutrient removal technologies can effectively reduce eutrophication risk, but can have unintended negative consequences on human and environmental health. Alternatives, such as algae-based treatment systems, improve the sustainability of the nutrient recovery process by producing biomass that can be converted to biofuel. However, research is needed to increase the productivity of algal treatment systems to improve their economic viability. Because algae in wastewater treatment systems are grown in wastewater rich in nutrients, the algae could become limited by dissolved inorganic carbon. This hypothesis was tested in 1.2 m long recirculating floways (n = 8 for each treatment/control) by quantifying algal dry mass and wastewater nutrient concentrations in 3 independent experiments: (1) carbon dioxide gas infused vs air infused control; (2) hydrochloric acid acidified vs neutralized solution control vs no chemical addition control; and (3) sodium bicarbonate addition vs no chemical control. Results showed increases in algal biomass after 18 days in wastewater augmented with dissolved inorganic carbon (carbon dioxide or sodium bicarbonate). In contrast, maintaining wastewater at near neutral pH with hydrochloric acid reduced algal productivity relative to controls. Nutrient reductions generally paralleled algal biomass increases except in the bicarbonate addition experiment. These findings provide evidence for the importance of carbon limitation in algal wastewater treatment floways. These results could help explain why carbon dioxide infusions stimulate algae in treatment systems. Furthermore, these results suggest that algae in nutrient enriched, sun-exposed streams (e.g., agricultural ditches or urbanized streams) may become carbon limited during peak periods of productivity. These findings could have important implications for ecosystems undergoing eutrophication as atmospheric carbon dioxide concentrations continue to rise.

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Section: Discussionmentioning

confidence: 99%

Carbon limitation in hypereutrophic, periphytic algal wastewater treatment systems

Furnish

Keller

2020

PLoS ONE

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“…We compared the primary structures of the viral Fds with 807 cyanobacterial Fds obtained from a recent genome mining effort (36). Zea mays Fd (zm-Fd1) was included as a frame of reference because this protein has been intensively studied (37,38).…”

Section: Cyanophage and Host Fds: Evolutionary Linksmentioning

confidence: 99%

Prochlorococcusphage ferredoxin: structural characterization and electron transfer to cyanobacterial sulfite reductases

Campbell

Olmos

et al. 2020

Preprint

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Marine cyanobacteria are infected by phage whose genomes encode ferredoxin (Fd) electron carriers. While these Fds are thought to redirect the energy harvested from light to phage-encoded oxidoreductases that enhance viral fitness, it is not clear how the biochemical and biophysical properties of phage Fds relate to those in photosynthetic organisms. Bioinformatic analysis using a sequence similarity network revealed that phage Fds are most closely related to cyanobacterial Fds that transfer electrons from photosystems to oxidoreductases involved in nutrient assimilation. Structural analysis of myovirus P-SSM2 Fd (pssm2-Fd), which infects Prochlorococcus marinus, revealed high similarity to cyanobacterial Fds (≤0.5 Å RMSD). Additionally, pssm2-Fd exhibits a low midpoint reduction potential (-336 mV vs. SHE) similar to other photosynthetic Fds, albeit lower thermostability (Tm = 28°C) than many Fds. When expressed in an Escherichia coli strain with a sulfite assimilation defect, pssm2-Fd complemented growth when coexpressed with a Prochlorococcus marinus sulfite reductase, revealing that pssm2-Fd can transfer electrons to a host protein involved in nutrient assimilation. The high structural similarity with cyanobacterial Fds and reactivity with a host sulfite reductase suggests that phage Fds evolved to transfer electrons to both phage-and cyanobacterial-encoded oxidoreductases.

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“…The bioethanol production is based on the fermentation of sugarcane juice or mixtures of broth and molasses by the yeast Saccharomyces cerevisiae achieving a concentration of 7–10% (v/v) ethanol after 6–10 h, when its own metabolite becomes toxic to the yeast and compromises the process viability (Santos et al, 2020 ). Yeast cells are collected at the end of fermentation cycle and a liquid-rich byproduct is obtained, sugarcane vinasse, which is an acid suspension with high COD values and accounts 10–15 L for each liter of produced ethanol (Christofoletti et al, 2013 ; Reis and Hu, 2017 ).…”

Section: Introductionmentioning

confidence: 99%

Polyhydroxyalkanoate Synthesis by Burkholderia glumae into a Sustainable Sugarcane Biorefinery Concept

Paula

Paula-Elias

Rodrigues

et al. 2021

Front. Bioeng. Biotechnol.

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Polyhydroxyalkanoate (PHA) bioplastic was synthesized by Burkholderia glumae MA13 from carbon sources and industrial byproducts related to sugarcane biorefineries: sucrose, xylose, molasses, vinasse, bagasse hydrolysate, yeast extract, yeast autolysate, and inactivated dry yeast besides different inorganic nitrogen sources. Sugarcane molasses free of pre-treatment was the best carbon source, even compared to pure sucrose, with intracellular polymer accumulation values of 41.1–46.6% cell dry weight. Whereas, xylose and bagasse hydrolysate were poor inducers of microbial growth and polymer synthesis, the addition of 25% (v/v) sugarcane vinasse to the culture media containing molasses was not deleterious and resulted in a statistically similar maximum polymer content of 44.8% and a maximum PHA yield of 0.18 g/g, at 34°C and initial pH of 6.5, which is economic and ecologically interesting to save water required for the industrial processes and especially to offer a fermentative recycling for this final byproduct from bioethanol industry, as an alternative to its inappropriate disposal in water bodies and soil contamination. Ammonium sulfate was better even than tested organic nitrogen sources to trigger the PHA synthesis with polymer content ranging from 29.7 to 44.8%. GC-MS analysis showed a biopolymer constituted mainly of poly(3-hydroxybutyrate) although low fractions of 3-hydroxyvalerate monomer were achieved, which were not higher than 1.5 mol% free of copolymer precursors. B. glumae MA13 has been demonstrated to be adapted to synthesize bioplastics from different sugarcane feedstocks and corroborates to support a biorefinery concept with value-added green chemicals for the sugarcane productive chain with additional ecologic benefits into a sustainable model.

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Evolutionary Relationships Between Low Potential Ferredoxin and Flavodoxin Electron Carriers

Cited by 46 publications

References 103 publications

Carbon limitation in hypereutrophic, periphytic algal wastewater treatment systems

Carbon limitation in hypereutrophic, periphytic algal wastewater treatment systems

Prochlorococcusphage ferredoxin: structural characterization and electron transfer to cyanobacterial sulfite reductases

Polyhydroxyalkanoate Synthesis by Burkholderia glumae into a Sustainable Sugarcane Biorefinery Concept

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