In some embodiments, the present invention provides a recombinant protein comprising an affinity tag configured to attach the recombinant protein to a silicate surface, fused to a hydrogen sulfide scavenging enzyme.

The present disclosure identifies pathways, mechanisms, systems and methods to confer chemoautotrophic production of carbon-based products of interest, such as sugars, alcohols, chemicals, amino acids, polymers, fatty acids and their derivatives, hydrocarbons, isoprenoids, and intermediates thereof, in organisms such that these organisms efficiently convert inorganic carbon to organic carbon-based products of interest using inorganic energy, such as formate, and in particular the use of organisms for the commercial production of various carbon-based products of interest.

Cysteine synthase enzymes (e.g. O-Acetyl-L-Serine Sulfhydrylase enzymes) may be used in combination with sulfide quinone reductase enzymes in additive compositions, fluid compositions, and methods for decreasing or removing hydrogen sulfide from recovered downhole fluids and/or the subterranean reservoir wellbore from which the downhole fluid was recovered. The fluid composition may include at least one cysteine synthase enzyme with at least one sulfide quinone reductase, and a base fluid, such as a water-based fluid, an organic-based fluid, and combinations thereof.

The present disclosure identifies pathways, mechanisms, systems and methods to confer chemoautotrophic production of carbon-based products of interest, such as sugars, alcohols, chemicals, amino acids, polymers, fatty acids and their derivatives, hydrocarbons, isoprenoids, and intermediates thereof, in organisms such that these organisms efficiently convert inorganic carbon to organic carbon-based products of interest using inorganic energy, such as formate, and in particular the use of organisms for the commercial production of various carbon-based products of interest.

The present disclosure identifies pathways, mechanisms, systems and methods to confer chemoautotrophic production of carbon-based products of interest, such as sugars, alcohols, chemicals, amino acids, polymers, fatty acids and their derivatives, hydrocarbons, isoprenoids, and intermediates thereof, in organisms such that these organisms efficiently convert inorganic carbon to organic carbon-based products of interest using inorganic energy, such as formate, and in particular the use of organisms for the commercial production of various carbon-based products of interest.

In some embodiments, the present invention provides a recombinant protein comprising an affinity tag configured to attach the recombinant protein to a silicate surface, fused to a hydrogen sulfide scavenging enzyme.

In some embodiments, the present invention provides a recombinant protein comprising an affinity tag configured to attach the recombinant protein to a silicate surface, fused to a hydrogen sulfide scavenging enzyme.

This disclosure provides a method for scavenging hydrogen sulfide (H.sub.2S) from a fluid containing H.sub.2S and metal ions by introducing into the fluid at least one metal chelant in an amount effective to chelate metal ions in the fluid to form at least one metal-chelate complex; and removing at least a portion of the H.sub.2S from the fluid with an effective amount of the at least one metal-chelate complex. The method may further comprise the step of introducing at least one enzyme having an ability to scavenge H.sub.2S into the fluid in an amount effective to scavenge H.sub.2S from the fluid, where the amount of the at least one metal-chelate complex is effective to influence the ability of the at least one enzyme to scavenge H.sub.2S.

A method of reducing an amount of a sulfur-containing compound in a reservoir fluid includes contacting a treatment fluid comprising an aqueous medium and an enzymatic scavenger with a precipitating fluid to precipitate the enzymatic scavenger; contacting the precipitated enzymatic scavenger with the reservoir fluid comprising the sulfur-containing compound; and reducing a number of the sulfur-containing compound in the reservoir fluid.

A method of reducing an amount of a sulfur-containing compound in a reservoir fluid includes contacting a treatment fluid comprising an aqueous medium and an enzymatic scavenger with a precipitating fluid to precipitate the enzymatic scavenger; contacting the precipitated enzymatic scavenger with the reservoir fluid comprising the sulfur-containing compound; and reducing a number of the sulfur-containing compound in the reservoir fluid.