Methods and fluid compositions are provided for decreasing an amount of sulfur-containing compounds in downhole fluids and/or subterranean reservoir wellbores by including at least one enzyme destabilizer in a fluid composition. The fluid composition may then be circulated into a subterranean reservoir wellbore. The fluid composition may further include a base fluid and at least one sulfur producing enzyme. The base fluid may be or include, but is not limited to, drilling fluids, servicing fluids, production fluids, completion fluids, injection fluids, refinery fluids, and combinations thereof. The enzyme destabilizer(s) may be destabilize the sulfur producing enzymes and thereby decrease an amount of sulfur-containing compounds produced vis-à-vis the sulfur producing enzyme(s).

The present invention discloses a Streptomyces sp. strain and a method for preparing a sulfide oxidase preparation from the same. This strain is a Streptomyces sp. strain DS021-Z.sub.5D.sub.2 which is a mutant having a high yield of sulfide oxidase obtained by taking a Streptomyces sp. strain DS021 as a starting strain and performing strain mutation by means of compound mutation of ultraviolet light and diethyl sulfate, and the preservation number is CGMCC No. 12808. This strain has the advantages of quick growth speed, high enzymatic productivity and the like. When this strain is fermented by a high-density fermentation method, this strain can produce sulfide oxidase preparations at a high yield. This strain has the advantages of inexpensive and easily-available culture substrates, high enzymatic productivity, short fermentation period, low production and use cost, and the like.

The present invention discloses a Streptomyces sp. strain and a method for preparing a sulfide oxidase preparation from the same. This strain is a Streptomyces sp. strain DS021-Z.sub.5D.sub.2 which is a mutant having a high yield of sulfide oxidase obtained by taking a Streptomyces sp. strain DS021 as a starting strain and performing strain mutation by means of compound mutation of ultraviolet light and diethyl sulfate, and the preservation number is CGMCC No. 12808. This strain has the advantages of quick growth speed, high enzymatic productivity and the like. When this strain is fermented by a high-density fermentation method, this strain can produce sulfide oxidase preparations at a high yield. This strain has the advantages of inexpensive and easily-available culture substrates, high enzymatic productivity, short fermentation period, low production and use cost, and the like.