Inactivation of uptake hydrogenase leads to enhanced and sustained hydrogen production with high nitrogenase activity under high light exposure in the cyanobacterium Anabaena siamensis TISTR 8012

AbstractThe response of net photosynthesis, dark respiration and acetylene reduction to temperature, moisture and light intensity were examined for Stereocaulon virgatum growing in the cloud/shroud zone on the tropical volcano La Soufrière, Guadeloupe, French West Indies. Rates for both acetylene reduction and net photosynthesis were maximal at saturating water contents, a pattern attributed to the finely branched nature of the phyllocladoid branchlets and the exposed position of spherical cephalodia, both of which minimize the formation of surface and interhyphal water films. Under conditions typical of those during cloud/shroud periods (13–16°C), thalli of S. virgatum exhibit many characteristics seen in other shade-tolerant lichen species. Net photosynthesis was light saturated at 300 μmol m−2 s−1 PAR, while the photocompensation point was less than 25 µmol m−2 s−1 PAR. Net photosynthetic uptake of carbon dioxide was optimal at 27–34°C, at which point light saturation was near 700 µmol m−2 s−1 PAR and the photocompensation point between 50 and 100 µmol m−2 s−1 PAR. Thalli of S. virgatin exhibited temperature-dependent sensitivity to high insolation. Only at 20°C were thalli able to tolerate high light exposure without reduction of apparent quantum yield. Exposure to high light intensity at 40°C inhibited the apparent quantum yield by almost 40% and acetylene reduction by 95%. This suggests brief periods of insolation shock may exert an influence disproportionately higher than either their frequency or duration. Thalli are normally exposed to cloud/shroud conditions but net photosynthetic uptake was maximal only during periods of elevated thallus temperature experienced at the onset of an insolation shock. However, with prolonged high insolation exposure and further elevation of thallus temperatures and thallus desiccation, severe impairment of subsequent photosynthetic activity ensues. S. virgatum may be characterized as a shade-tolerant species but its physiology is more adapted in some respects to conditions experienced during rare periods of full insolation.

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Bioenergetics of lactate vs. acetate outside TCA enhanced the hydrogen evolution levels in two newly isolated strains of the photosynthetic bacterium Rhodopseudomonas

Zeitschrift für Naturforschung C ◽

10.1515/znc-2016-0070 ◽

2017 ◽

Vol 72 (3-4) ◽

pp. 99-105

Author(s):

Amal W. Danial ◽

Ahmed M. Abdel Wahab ◽

Houssam H. Arafat ◽

Refat Abdel-Basset

Keyword(s):

Hydrogen Production ◽

Hydrogen Evolution ◽

Immobilized Cells ◽

Nitrogenase Activity ◽

Photosynthetic Bacterium ◽

Free Cell ◽

Dairy Wastewater ◽

Purple Nonsulfur Bacteria ◽

Uptake Hydrogenase ◽

Production Growth

Abstract Two local hydrogen-evolving strains of purple nonsulfur bacteria have been isolated, characterized, and identified as Rhodopseudomonas sp. TUT (strains Rh1 and Rh2). Lactate followed by succinate and malate supported the highest amounts of H2 production, growth (O.D.660nm, proteins and bacteriochlorphyll contents), nitrogenase activity, and uptake hydrogenase; the least of which was acetate. Alginate-immobilized cells evolved higher hydrogen amounts than free cell counterparts. Rh1 was more productive than Rh2 at all circumstances. Lactate-dependent hydrogen evolution was more than twice that of acetate, due to ATP productivity (2/–1, respectively), which is limiting to the nitrogenase activity. The preference of lactate over other acids indicates the feasibility of using these two strains in hydrogen production from dairy wastewater.

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Nucleotide sequencing and transcriptional analysis of uptake hydrogenase genes in the filamentous N2-fixing cyanobacterium Anabaena siamensis

Journal of Applied Phycology ◽

10.1007/s10811-006-9077-z ◽

2006 ◽

Vol 18 (6) ◽

pp. 713-722 ◽

Cited By ~ 5

Author(s):

Saranya Phunpruch ◽

Wipawee Baebprasert ◽

Chamaporn Thongpeng ◽

Aran Incharoensakdi

Keyword(s):

Transcriptional Analysis ◽

Nucleotide Sequencing ◽

Uptake Hydrogenase ◽

Cyanobacterium Anabaena ◽

Anabaena Siamensis

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Increase and Stabilization of Photoproduction of Hydrogen in Nostoc muscorum by Photosynthetic Electron Transport Inhibitors

Zeitschrift für Naturforschung C ◽

10.1515/znc-1978-7-815 ◽

1978 ◽

Vol 33 (7-8) ◽

pp. 541-547 ◽

Cited By ~ 28

Author(s):

Hartmut Spiller ◽

Anneliese Ernst ◽

Wolfgang Kerfin ◽

Peter Böger

Keyword(s):

Electron Transport ◽

Hydrogen Production ◽

Partial Pressure ◽

Packed Cell Volume ◽

Nitrogenase Activity ◽

Photosynthetic Electron Transport ◽

Nostoc Muscorum ◽

Uptake Hydrogenase ◽

Partial Pressure Of Oxygen ◽

Transport Inhibitors

Abstract Nittrogen-fixing cells of Nostoc muscorum grown under nitrogen or in the presence of nitrate exhibit substantial light-induced hydrogen production for over 15 hours in the presence of electron transport inhibitors. Rates attain levels of 12 μmol H2 evolved/ml packed cell volume and hour. The ATP-dependent nitrogenase, not a hydrogenase, is responsible for hydrogen production. This is indicated by poor sensitivity to CO and inhibition of the reaction by uncouplers, acetylene, and N2 . An active uptake hydrogenase minimizes light-induced H2 production. Although nitrogenase activity is somewhat decreased by several photosynthetic electron transport inhibitors, hydrogen production is markedly increased. This is due to lowering the partial pressure of oxygen in the cell, preventing oxidative hydrogen consumption.

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Azotobacter vinelandiiNitrogenase Activity, Hydrogen Production, and Response to Oxygen Exposure

Applied and Environmental Microbiology ◽

10.1128/aem.01208-18 ◽

2018 ◽

Vol 84 (16) ◽

Cited By ~ 4

Author(s):

Jace Natzke ◽

Jesse Noar ◽

José M. Bruno-Bárcena

Keyword(s):

Hydrogen Production ◽

Nitrogenase Activity ◽

Hydrogen Gas ◽

Uptake Hydrogenase ◽

Exposure Limits ◽

Activity Data ◽

Content Type ◽

Oxygen Exposure

ABSTRACTAzotobacter vinelandiiselectively utilizes three types of nitrogenase (molybdenum, vanadium, and iron only) to fix N2, with their expression regulated by the presence or absence of different metal cofactors in its environment. Each alternative nitrogenase isoenzyme is predicted to have different electron flux requirements based onin vitromeasurements, with the molybdenum nitrogenase requiring the lowest flux and the iron-only nitrogenase requiring the highest. Here, prior characterized strains, derepressed in nitrogenase synthesis and also deficient in uptake hydrogenase, were further modified to generate new mutants lacking the ability to produce poly-β-hydroxybutyrate (PHB). PHB is a storage polymer generated under oxygen-limiting conditions and can represent up to 70% of the cells' dry weight. The absence of such granules facilitated the study of relationships between catalytic biomass and product molar yields across different adaptive respiration conditions. The released hydrogen gas observed during growth, due to the inability of the mutants to recapture hydrogen, allowed for direct monitoring ofin vivonitrogenase activity for each isoenzyme. The data presented here show that increasing oxygen exposure limits equally thein vivoactivities of all nitrogenase isoenzymes, while under comparative conditions, the Mo nitrogenase enzyme evolves more hydrogen per unit of biomass than the alternative isoenzymes.IMPORTANCEA. vinelandiihas been a focus of intense research for over 100 years. It has been investigated for a variety of functions, including agricultural fertilization and hydrogen production. All of these endeavors are centered aroundA. vinelandii's ability to fix nitrogen aerobically using three nitrogenase isoenzymes. The majority of research up to this point has targetedin vitromeasurements of the molybdenum nitrogenase, and robust data contrasting how oxygen impacts thein vivoactivity of each nitrogenase isoenzyme are lacking. This article aims to providein vivonitrogenase activity data using a real-time evaluation of hydrogen gas released by derepressed nitrogenase mutants lacking an uptake hydrogenase and PHB accumulation.

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