Cationic polyelectrolytes (chitosan, poly-l-lysine (PLL), polyethyleneimine (PEI) and trimethylam... more Cationic polyelectrolytes (chitosan, poly-l-lysine (PLL), polyethyleneimine (PEI) and trimethylammonium glycol chitosan iodide (TGCI)) were used to entrap anoxygenic phototrophic bacteria in order to prevent the inhibitory effect of NH4+ on hydrogen production. When combined with agar gel, chitosan and PLL demonstrated no obvious repressive effect on hydrogen production by Rhodobacter sphaeroides under light-anaerobic conditions with lactate and glutamate as the
International Journal of Biological Macromolecules, 1999
Regulatory mechanism in PHB [poly-(hydroxybutyrate)] accumulation by cyanobacteria, especially by... more Regulatory mechanism in PHB [poly-(hydroxybutyrate)] accumulation by cyanobacteria, especially by a thermophilic isolate, Synechococcus MA19 was reviewed in comparison with a genetically engineered strain. The strain, MA19 accumulates PHB under nitrogen starved and photoautotrophic conditions (MA19-N). Little PHB synthase activity was detected in crude extracts from the cells grown in nitrogen sufficient conditions (MA19+N). The activity was detected exclusively in
Effect of pH of culture media on intracellular accumulation of poly-(hydroxybutyrate) (PHB) by a ... more Effect of pH of culture media on intracellular accumulation of poly-(hydroxybutyrate) (PHB) by a non-sulfur photosynthetic bacterium, Rhodobacter sphaeroides strain RV was studied in pH-stat cultures. Sub-optimal pH for growth, 8.0 or 8.5 gave the higher content of PHB rather than optimal pH 7.5 for growth. These results show that growth and PHB accumulation of the bacteria can be controlled
Biochimica Et Biophysica Acta-gene Structure and Expression, 2000
The Clostridium pasteurianum hydrogenase I has been expressed in the cyanobacterium Synechococcus... more The Clostridium pasteurianum hydrogenase I has been expressed in the cyanobacterium Synechococcus PCC7942. The Shine–Dalgarno sequence of the structural gene encoding hydrogenase I from C. pasteurianum was changed to that of the cat (chloramphenicol acetyltransferase) gene. The hydrogenase gene was cloned downstream of a strong promoter, isolated from Synechococcus PCC7942, with the cat gene as a reporter gene. Expression of
Clostridial hydrogenase was introduced into a cyanobacterium, Synechococcus elongatus, by direct ... more Clostridial hydrogenase was introduced into a cyanobacterium, Synechococcus elongatus, by direct electroporation. The introduced hydrogenase activity was 11 nmol H evolved with reduced Methyl Viologen per mg chlorophyll. The cells with clostridial hydrogenase showed simultaneous light-dependent evolution of H and O . This method will be applicable to assess a variety of hydrogenases for hydrogen production coupled with cyanobacterial photo-synthesis.
A method for improving the adsorption of bacteria on glass surfaces was developed. The modificati... more A method for improving the adsorption of bacteria on glass surfaces was developed. The modification of a glass surface by LS-2480 greatly increased the number of bacteria that were immobilized. The conditions for bacteria immobilization on the modified glass surface were optimized.
A thermophilic cyanobacterium strain MA19 that photoautotrophically accumulates a high amount of ... more A thermophilic cyanobacterium strain MA19 that photoautotrophically accumulates a high amount of poly-β-hydroxybutyrate (PHB) was isolated and identified as Synechococcus sp. This strain accumulated PHB at more than 20% of the dry cell weight after the cells were cultivated in a nitrogen-free inorganic medium aerated with 2% CO2. The PHB content was the highest in all the photoautotrophic organisms. PHB
Hydrogen production with glucose by using co-immobilized cultures of a lactic acid bacterium, Lac... more Hydrogen production with glucose by using co-immobilized cultures of a lactic acid bacterium, Lactobacillus delbrueckii NBRC13953, and a photosynthetic bacterium, Rhodobacter sphaeroides RV, in agar gels was studied. Glucose was converted to hydrogen gas in a yield of 7.1mol of hydrogen per mole of glucose at a maximum under illuminated conditions.
The study of biological hydrogen production by using photosynthetic bacteria and cyanobacteria is... more The study of biological hydrogen production by using photosynthetic bacteria and cyanobacteria is described based on a national R&D project in Japan. We describe here the subjects examined in the research for photosynthetic bacteria: analysis of the relationship between the penetration of light to photobioreactor and hydrogen production, genetic engineering of photosynthetic bacteria to control the pigment content for making
Our efforts have been aimed at the technological basis of photosynthetic-microbial production of ... more Our efforts have been aimed at the technological basis of photosynthetic-microbial production of materials and an energy carrier. We report here accumulation of poly-(3-hydroxybutyrate) (PHB), a raw material of biodegradable plastics and for production of hydrogen gas, and a renewable energy carrier by photosynthetic microorganisms (tentatively defined as cyanobacteria plus photosynthetic bateria, in this report). A thermophilic cyanobacterium,Synechococcus sp. MA19 that accumulates PHB at more than 20% of cell dry wt under nitrogen-starved conditions was isolated and microbiologically identified. The mechanism of PHB accumulation was studied. A mesophilicSynechococcus PCC7942 was transformed with the genes encoding PHB-synthesizing enzymes fromAlcaligenes eutrophus. The transformant accumulated PHB under nitrogen-starved conditions. The optimal conditions for PHB accumulation by a photosynthetic bacterium grown on acetate were studied. Hydrogen production by photosynthetic microorganisms was studied. Cyanobacteria can produce hydrogen gas by nitrogenase or hydrogenase. Hydrogen production mediated by native hydrogenase in cyanobacteria was revealed to be in the dark anaerobic degradation of intracellular glycogen. A new system for light-dependent hydrogen production was targeted.In vitro andin vivo coupling of cyanobacterial ferredoxin with a heterologous hydrogenase was shown to produce hydrogen under light conditions. A trial for genetic trasformation ofSynechococcus PCC7942 with the hydrogenase gene fromClostridium pasteurianum is going on. The strong hydrogen producers among photosynthetic bacteria were isolated and characterized. Co-culture ofRhodobacter andClostriumdium was applied to produce hydrogen from glucose. Conversely in the case of cyanobacteria, genetic regulation of photosynthetic proteins was intended to improve conversion efficiency in hydrogen production by the photosynthetic bacterium,Rhodobacter sphaeroides RV. A mutant acquired by UV irradiation will be characterized for the mutation and for hydrogen productivity in comparison with the wild type strain. Some basic studies to develop photobioreactors are also introduced.
Hydrogen evolution by a nitrogen-fixing cyanobacterium, Anabaena sp. strain N-7363, was tested in... more Hydrogen evolution by a nitrogen-fixing cyanobacterium, Anabaena sp. strain N-7363, was tested in order to develop a water biophotolysis system under aerobic conditions. A culture of the strain supplemented with carbon dioxide under an air atmosphere evolved hydrogen and oxygen gas, which reached final concentrations of 9.7 and 69.8%, respectively, after 12 days of incubation. Hydrogen uptake activity was not
ABSTRACT In order to use photosynthetic bacteria for efficient hydrogen production after anaerobi... more ABSTRACT In order to use photosynthetic bacteria for efficient hydrogen production after anaerobic hydrogen and acetate fermentation, hydrogen-producing activity from acetate by agar-immobilized photosynthetic bacteria was evaluated under light-illuminated conditions. Among the tested 5 strains, Rhodobacter sphaeroides RV gave similar rate of hydrogen production as the case of lactate, and the yield was as high as 2.65–2.81 mol of hydrogen per mol of acetate consumed. R. sphaeroides IL106 gave the highest yield of 3.03 mol of hydrogen per acetate when acetate concentration was low.
A stable mutant of the photosynthetic bacterium Rhodobacter sphaeroides with an altered light-har... more A stable mutant of the photosynthetic bacterium Rhodobacter sphaeroides with an altered light-harvesting (LH) system (P3 mutant) was obtained by UV irradiation and characterized. The mutant exhibited a 2.7-fold decrease in the core antennal (LH1) content and 1.6-fold increase in peripheral antennal (LH2) content compared to the wild-type strain. The H2 evolution rates in the P3 mutant under 800- and
The principles and recent progress in the research and development of photobiological hydrogen pr... more The principles and recent progress in the research and development of photobiological hydrogen production are reviewed. Cyanobacteria produce hydrogen gas using nitrogenase and/or hydrogenase. Hydrogen production mediated by native hydrogenases in cyanobacteria occurs under in the dark under anaerobic conditions by degradation of intracellular glycogen. In vitro and in vivo coupling of the cyanobacterial photosynthetic system with a clostridial hydrogenase
Cationic polyelectrolytes (chitosan, poly-l-lysine (PLL), polyethyleneimine (PEI) and trimethylam... more Cationic polyelectrolytes (chitosan, poly-l-lysine (PLL), polyethyleneimine (PEI) and trimethylammonium glycol chitosan iodide (TGCI)) were used to entrap anoxygenic phototrophic bacteria in order to prevent the inhibitory effect of NH4+ on hydrogen production. When combined with agar gel, chitosan and PLL demonstrated no obvious repressive effect on hydrogen production by Rhodobacter sphaeroides under light-anaerobic conditions with lactate and glutamate as the
International Journal of Biological Macromolecules, 1999
Regulatory mechanism in PHB [poly-(hydroxybutyrate)] accumulation by cyanobacteria, especially by... more Regulatory mechanism in PHB [poly-(hydroxybutyrate)] accumulation by cyanobacteria, especially by a thermophilic isolate, Synechococcus MA19 was reviewed in comparison with a genetically engineered strain. The strain, MA19 accumulates PHB under nitrogen starved and photoautotrophic conditions (MA19-N). Little PHB synthase activity was detected in crude extracts from the cells grown in nitrogen sufficient conditions (MA19+N). The activity was detected exclusively in
Effect of pH of culture media on intracellular accumulation of poly-(hydroxybutyrate) (PHB) by a ... more Effect of pH of culture media on intracellular accumulation of poly-(hydroxybutyrate) (PHB) by a non-sulfur photosynthetic bacterium, Rhodobacter sphaeroides strain RV was studied in pH-stat cultures. Sub-optimal pH for growth, 8.0 or 8.5 gave the higher content of PHB rather than optimal pH 7.5 for growth. These results show that growth and PHB accumulation of the bacteria can be controlled
Biochimica Et Biophysica Acta-gene Structure and Expression, 2000
The Clostridium pasteurianum hydrogenase I has been expressed in the cyanobacterium Synechococcus... more The Clostridium pasteurianum hydrogenase I has been expressed in the cyanobacterium Synechococcus PCC7942. The Shine–Dalgarno sequence of the structural gene encoding hydrogenase I from C. pasteurianum was changed to that of the cat (chloramphenicol acetyltransferase) gene. The hydrogenase gene was cloned downstream of a strong promoter, isolated from Synechococcus PCC7942, with the cat gene as a reporter gene. Expression of
Clostridial hydrogenase was introduced into a cyanobacterium, Synechococcus elongatus, by direct ... more Clostridial hydrogenase was introduced into a cyanobacterium, Synechococcus elongatus, by direct electroporation. The introduced hydrogenase activity was 11 nmol H evolved with reduced Methyl Viologen per mg chlorophyll. The cells with clostridial hydrogenase showed simultaneous light-dependent evolution of H and O . This method will be applicable to assess a variety of hydrogenases for hydrogen production coupled with cyanobacterial photo-synthesis.
A method for improving the adsorption of bacteria on glass surfaces was developed. The modificati... more A method for improving the adsorption of bacteria on glass surfaces was developed. The modification of a glass surface by LS-2480 greatly increased the number of bacteria that were immobilized. The conditions for bacteria immobilization on the modified glass surface were optimized.
A thermophilic cyanobacterium strain MA19 that photoautotrophically accumulates a high amount of ... more A thermophilic cyanobacterium strain MA19 that photoautotrophically accumulates a high amount of poly-β-hydroxybutyrate (PHB) was isolated and identified as Synechococcus sp. This strain accumulated PHB at more than 20% of the dry cell weight after the cells were cultivated in a nitrogen-free inorganic medium aerated with 2% CO2. The PHB content was the highest in all the photoautotrophic organisms. PHB
Hydrogen production with glucose by using co-immobilized cultures of a lactic acid bacterium, Lac... more Hydrogen production with glucose by using co-immobilized cultures of a lactic acid bacterium, Lactobacillus delbrueckii NBRC13953, and a photosynthetic bacterium, Rhodobacter sphaeroides RV, in agar gels was studied. Glucose was converted to hydrogen gas in a yield of 7.1mol of hydrogen per mole of glucose at a maximum under illuminated conditions.
The study of biological hydrogen production by using photosynthetic bacteria and cyanobacteria is... more The study of biological hydrogen production by using photosynthetic bacteria and cyanobacteria is described based on a national R&D project in Japan. We describe here the subjects examined in the research for photosynthetic bacteria: analysis of the relationship between the penetration of light to photobioreactor and hydrogen production, genetic engineering of photosynthetic bacteria to control the pigment content for making
Our efforts have been aimed at the technological basis of photosynthetic-microbial production of ... more Our efforts have been aimed at the technological basis of photosynthetic-microbial production of materials and an energy carrier. We report here accumulation of poly-(3-hydroxybutyrate) (PHB), a raw material of biodegradable plastics and for production of hydrogen gas, and a renewable energy carrier by photosynthetic microorganisms (tentatively defined as cyanobacteria plus photosynthetic bateria, in this report). A thermophilic cyanobacterium,Synechococcus sp. MA19 that accumulates PHB at more than 20% of cell dry wt under nitrogen-starved conditions was isolated and microbiologically identified. The mechanism of PHB accumulation was studied. A mesophilicSynechococcus PCC7942 was transformed with the genes encoding PHB-synthesizing enzymes fromAlcaligenes eutrophus. The transformant accumulated PHB under nitrogen-starved conditions. The optimal conditions for PHB accumulation by a photosynthetic bacterium grown on acetate were studied. Hydrogen production by photosynthetic microorganisms was studied. Cyanobacteria can produce hydrogen gas by nitrogenase or hydrogenase. Hydrogen production mediated by native hydrogenase in cyanobacteria was revealed to be in the dark anaerobic degradation of intracellular glycogen. A new system for light-dependent hydrogen production was targeted.In vitro andin vivo coupling of cyanobacterial ferredoxin with a heterologous hydrogenase was shown to produce hydrogen under light conditions. A trial for genetic trasformation ofSynechococcus PCC7942 with the hydrogenase gene fromClostridium pasteurianum is going on. The strong hydrogen producers among photosynthetic bacteria were isolated and characterized. Co-culture ofRhodobacter andClostriumdium was applied to produce hydrogen from glucose. Conversely in the case of cyanobacteria, genetic regulation of photosynthetic proteins was intended to improve conversion efficiency in hydrogen production by the photosynthetic bacterium,Rhodobacter sphaeroides RV. A mutant acquired by UV irradiation will be characterized for the mutation and for hydrogen productivity in comparison with the wild type strain. Some basic studies to develop photobioreactors are also introduced.
Hydrogen evolution by a nitrogen-fixing cyanobacterium, Anabaena sp. strain N-7363, was tested in... more Hydrogen evolution by a nitrogen-fixing cyanobacterium, Anabaena sp. strain N-7363, was tested in order to develop a water biophotolysis system under aerobic conditions. A culture of the strain supplemented with carbon dioxide under an air atmosphere evolved hydrogen and oxygen gas, which reached final concentrations of 9.7 and 69.8%, respectively, after 12 days of incubation. Hydrogen uptake activity was not
ABSTRACT In order to use photosynthetic bacteria for efficient hydrogen production after anaerobi... more ABSTRACT In order to use photosynthetic bacteria for efficient hydrogen production after anaerobic hydrogen and acetate fermentation, hydrogen-producing activity from acetate by agar-immobilized photosynthetic bacteria was evaluated under light-illuminated conditions. Among the tested 5 strains, Rhodobacter sphaeroides RV gave similar rate of hydrogen production as the case of lactate, and the yield was as high as 2.65–2.81 mol of hydrogen per mol of acetate consumed. R. sphaeroides IL106 gave the highest yield of 3.03 mol of hydrogen per acetate when acetate concentration was low.
A stable mutant of the photosynthetic bacterium Rhodobacter sphaeroides with an altered light-har... more A stable mutant of the photosynthetic bacterium Rhodobacter sphaeroides with an altered light-harvesting (LH) system (P3 mutant) was obtained by UV irradiation and characterized. The mutant exhibited a 2.7-fold decrease in the core antennal (LH1) content and 1.6-fold increase in peripheral antennal (LH2) content compared to the wild-type strain. The H2 evolution rates in the P3 mutant under 800- and
The principles and recent progress in the research and development of photobiological hydrogen pr... more The principles and recent progress in the research and development of photobiological hydrogen production are reviewed. Cyanobacteria produce hydrogen gas using nitrogenase and/or hydrogenase. Hydrogen production mediated by native hydrogenases in cyanobacteria occurs under in the dark under anaerobic conditions by degradation of intracellular glycogen. In vitro and in vivo coupling of the cyanobacterial photosynthetic system with a clostridial hydrogenase
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