A method of preparing ammonium sulfate includes feeding biosulfur and ammonia produced during anaerobic fermentation into a sulfur-oxidizing microbial reactor to cause sulfur-oxidizing microorganisms to produce sulfuric acid through oxidation of the biosulfur and reacting the produced sulfuric acid with ammonia to produce the ammonium sulfate. A culture medium containing the produced ammonium sulfate and microorganisms can be used as fertilizers.

The present invention relates to a monomeric polypeptide including a single subunit comprising the active site of a [NiFe]-hydrogenase-like protein, said monomeric polypeptide having hydrogenase activity.

The invention pertains to a method for synthesizing a product of interest by culturing a microalgal cell producing the product of interest in the dark in a culture medium comprising an organic acid as a fixed carbon source, wherein the microalgal cell is a facultative heterotroph. The product of interest can be a microalgal biomass, a pigment, terpene, recombinant molecule, biogas, or a precursor thereof. In an embodiment, the culture medium comprises urea as a primary source of nitrogen. In one embodiment, the microalgal cell belongs to the order Chlamydomonadales. A method of identifying and isolating a microalgal cell having a preferred characteristic that is suitable for synthesis of a product of interest is also provided, the method comprising identifying and isolating a non-mutagenized or recombinant microalgal cell from a microalgal culture using a fluorescence activated cell sorting technique and/or a phototaxic response.

The invention pertains to a method for synthesizing a product of interest by culturing a microalgal cell producing the product of interest in the dark in a culture medium comprising an organic acid as a fixed carbon source, wherein the microalgal cell is a facultative heterotroph. The product of interest can be a microalgal biomass, a pigment, terpene, recombinant molecule, biogas, or a precursor thereof. In an embodiment, the culture medium comprises urea as a primary source of nitrogen. In one embodiment, the microalgal cell belongs to the order Chlamydomonadales. A method of identifying and isolating a microalgal cell having a preferred characteristic that is suitable for synthesis of a product of interest is also provided, the method comprising identifying and isolating a non-mutagenized or recombinant microalgal cell from a microalgal culture using a fluorescence activated cell sorting technique and/or a phototaxic response.

Provided are a biomineralogical method for removing cesium ions. The method for removing cesium ions, the method comprising: adding metal-reducing bacteria, an iron source, and a sulfur source into a solution containing the cesium ions to convert the cesium ions into a solid mineral incorporating cesium. The method for removing cesium ions according to the present invention has advantages in that the cesium ions may be removed with high efficiency and small volume even in the case in which competing ions are present at a high concentration like sea water.

Provided are a biomineralogical method for removing cesium ions. The method for removing cesium ions, the method comprising: adding metal-reducing bacteria, an iron source, and a sulfur source into a solution containing the cesium ions to convert the cesium ions into a solid mineral incorporating cesium. The method for removing cesium ions according to the present invention has advantages in that the cesium ions may be removed with high efficiency and small volume even in the case in which competing ions are present at a high concentration like sea water.

A method for producing metal chalcogenide nanoparticles, the method comprising: (i) producing hydrogen chalcogenide-containing vapor from a microbial source, wherein said microbial source comprises: (a) chalcogen-reducing microbes capable of producing hydrogen chalcogenide vapor from a chalcogen-containing source; (b) a culture medium suitable for sustaining said chalcogen-reducing microbes; (c) at least one chalcogen-containing compound that can be converted to hydrogen chalcogenide vapor by said chalcogen-reducing microbes; and (d) at least one nutritive compound that provides donatable electrons to said chalcogen-reducing microbes during consumption of the nutritive compound by said chalcogen-reducing microbes; and (ii) directing said hydrogen chalcogenide-containing vapor into a metal-containing solution comprising a metal salt dissolved in a solvent to produce metal chalcogenide nanoparticles in said solution, wherein said chalcogen is sulfur or selenium, and said chalcogenide is sulfide or selenide, respectively. The invention is also directed to metal chalcogenide nanoparticle compositions produced as above and having distinctive properties.

A method for producing metal chalcogenide nanoparticles, the method comprising: (i) producing hydrogen chalcogenide-containing vapor from a microbial source, wherein said microbial source comprises: (a) chalcogen-reducing microbes capable of producing hydrogen chalcogenide vapor from a chalcogen-containing source; (b) a culture medium suitable for sustaining said chalcogen-reducing microbes; (c) at least one chalcogen-containing compound that can be converted to hydrogen chalcogenide vapor by said chalcogen-reducing microbes; and (d) at least one nutritive compound that provides donatable electrons to said chalcogen-reducing microbes during consumption of the nutritive compound by said chalcogen-reducing microbes; and (ii) directing said hydrogen chalcogenide-containing vapor into a metal-containing solution comprising a metal salt dissolved in a solvent to produce metal chalcogenide nanoparticles in said solution, wherein said chalcogen is sulfur or selenium, and said chalcogenide is sulfide or selenide, respectively. The invention is also directed to metal chalcogenide nanoparticle compositions produced as above and having distinctive properties.

A process for the biological production of hydrogen and/or methane by absorption and biological conversion of carbon dioxide, includes the steps of being performed by co-culture of one or more hydrogen-producing bacteria in at least one first reactor, and one or more acetogenic bacteria in at least one second reactor, and/or one or more methanogenic microorganisms in at least one third reactor.

A process for the biological production of hydrogen and/or methane by absorption and biological conversion of carbon dioxide, includes the steps of being performed by co-culture of one or more hydrogen-producing bacteria in at least one first reactor, and one or more acetogenic bacteria in at least one second reactor, and/or one or more methanogenic microorganisms in at least one third reactor.