# US 4,394,451 A · Culture medium and conditions for growth of magnetic bacteria > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 4,394,451 A - Document ID: US4394451A - Status: Granted - Kind: A - Application number: 06/202,160 - Filed: 1980-10-30 - Granted: 1983-07-19 - Earliest claimed: 1980-10-30 - Assignees: BioMagnetech Corp. - Inventors: Richard P. Blakemore; Ralph S. Wolfe - Web page: https://patentgrep.com/patent/US4394451A ## CPC - C12N 1/20: Bacteria; Culture media therefor - C12P 3/00: Preparation of elements or inorganic compounds except carbon dioxide {(recovery of carbon dioxides as by-products C12F3/02)} - Y10S 435/822: using bacteria or actinomycetales - C12N: MICROORGANISMS OR ENZYMES; COMPOSITIONS THEREOF; PROPAGATING, PRESERVING, OR MAINTAINING MICROORGANISMS; MUTATION OR GENETIC ENGINEERING; CULTURE MEDIA (microbiological testing media C12Q1/00) - C12P: FERMENTATION OR ENZYME-USING PROCESSES TO SYNTHESISE A DESIRED CHEMICAL COMPOUND OR COMPOSITION OR TO SEPARATE OPTICAL ISOMERS FROM A RACEMIC MIXTURE {(brewing of beer C12C; producing vinegar C12J; producing specific peptides or proteins C07K; producing enzymes C12N9/00; DNA or RNA concerning genetic engineering, vectors, e.g. plasmids, or their isolation, preparation or purification C12N15/00; measuring or testing processes involving enzymes or microorganisms C12Q; measuring or testing processes involving nucleic acid amplification reactions C12Q1/6844; fermentation processes to form a food composition, A21 or A23; compounds in general, see the relevant compound class, e.g. C01, C07)} - Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS ## Abstract A biologically pure culture of a bacterium of the genus Aquaspirillum, designated MS-1, has been found to contain chains (so-called magnetosomes) of single domain magnetite particles. The magnetite particles are roughly cubic and are about 500 A on a side. Each of the chains contains approximately 20 magnetite particles. These magnetite particles can be recovered from the bacterium and usefully employed in magnetic recording devices and the like. The biologically pure culture of the magnetic bacterium may be grown in a low oxygen environment and on a nutrient medium containing ferric quinate. ## Claims ### Claim 1 An aqueous culture medium for the growth of a biologically pure culture of magnetic bacteria, comprising, per 100 ml, about 2-30 .mu.M of ferric quinate, about 10-1000 mg of an organic compound selected from the group consisting of fumaric acid, tartaric acid, malic acid, succinic acid, lactic acid, pyruvic acid, oxaloacetic acid, malonic acid, .beta.-hydroxybutyric acid, maleic acid, galactose, rhamnose, melibiose, acetic acid, adipic acid, and glutaric acid, a vitamin source, a mineral source, a nitrogen source, an acetate source, and a pH buffer, said pH buffer resulting in a pH of said aqueous culture medium of about 5.2-7.5. ### Claim 2 (depends on 1) An aqueous culture medium in accordance with claim 1 wherein said vitamin source comprises about 0.25-2 ml of a vitamin elixir. ### Claim 3 (depends on 1) An aqueous culture medium in accordance with claim 1 wherein said mineral source comprises about 0.25-2 ml of a mineral elixir. ### Claim 4 (depends on 1) An aqueous culture medium in accordance with claim 1 wherein said nitrogen source comprises about 1-100 mg of an ammonium ion or nitrate ion source. ### Claim 5 (depends on 1) An aqueous culture medium in accordance with claim 1 wherein said acetate source comprises about 2-100 mg of acetic acid or a salt of acetic acid. ### Claim 6 (depends on 1) An aqueous culture medium in accordance with claim 1 wherein said pH buffer comprises about 0.1-5 mM of a phosphate buffer. ### Claim 7 (depends on 1) An aqueous culture medium in accordance with claim 1 also containing a reducing agent. ### Claim 8 (depends on 7) An aqueous culture medium in accordance with claim 7 wherein said reducing agent comprises about 2.5-50 mg of sodium thioglycolate. ### Claim 9 An aqueous culture medium for the growth of a biologically pure culture of magnetic bacteria, comprising, per 100 ml, about 2-30 .mu.M of ferric quinate, about 10-1000 mg of an organic acid selected from the group consisting of fumaric acid, tartaric acid, malic acid, succinic acid, lactic acid, pyruvic acid, oxaloacetic acid, malonic acid, .beta.-hydroxybutyric acid, and maleic acid, a vitamin source, a mineral source, about 1-100 mg of an ammonium ion or nitrate ion source, about 2-100 mg of acetic acid or a salt of acetic acid, about 0.1-5 mM of a phosphate buffer, about 2.5-50 mg of sodium thioglycolate, and the remainder substantially distilled water. ### Claim 10 (depends on 9) An aqueous culture medium in accordance with claim 9 wherein said organic acid is succinic acid. ### Claim 11 (depends on 9) An aqueous culture medium in accordance with claim 9 wherein said vitamin source comprises about 0.25-2 ml of a vitamin elixir. ### Claim 12 (depends on 9) An aqueous culture medium in accordance with claim 9 wherein said mineral source comprises about 0.25-2 ml of a mineral elixir. ### Claim 13 (depends on 9) An aqueous culture medium in accordance with claim 9 wherein said ammonium ion source is ammonium chloride. ### Claim 14 (depends on 9) An aqueous culture medium in accordance with claim 9 wherein said nitrate ion source is sodium nitrate. ### Claim 15 (depends on 9) An aqueous culture medium in accordance with claim 9 wherein said salt of acetic acid is sodium acetate. ### Claim 16 (depends on 9) An aqueous culture medium in accordance with claim 9 wherein said phosphate buffer is potassium dihydrogen phosphate. ### Claim 17 An aqueous culture medium for the growth of a biologically pure culture of magnetic bacteria, comprising, per 100 ml, about 25 .mu.M ferric quinate, about 100 mg of an organic acid selected from the group consisting of fumaric acid, tartaric acid, malic acid, succinic acid, lactic acid, pyruvic acid, oxaloacetic acid, malonic acid, .beta.-hydroxybutyric acid, and maleic acid, a vitamin source, a mineral source, about 10 mg of a nitrate source, about 20 mg of acetic acid or a salt of acetic acid, about 5 mM of a phosphate buffer, about 5 mg of sodium thioglycolate, and the remainder substantially distilled water. ### Claim 18 (depends on 17) An aqueous culture medium in accordance with claim 17 wherein said organic acid is succinic acid. ### Claim 19 (depends on 17) An aqueous culture medium in accordance with claim 17 wherein said vitamin source comprises about 1 ml of a vitamin elixir. ### Claim 20 (depends on 17) An aqueous culture medium in accordance with claim 17 wherein said mineral source comprises about 1 ml of a mineral elixir. ### Claim 21 (depends on 17) An aqueous culture medium in accordance with claim 17 wherein said nitrate source is sodium nitrate. ### Claim 22 (depends on 17) An aqueous culture medium in accordance with claim 17 wherein said salt of acetic acid is sodium acetate. ### Claim 23 (depends on 17) An aqueous culture medium in accordance with claim 17 wherein said phosphate buffer is potassium dihydrogen phosphate. ### Claim 24 (depends on 1, 12) An aqueous culture medium in accordance with claim 1, 12, or 20 also containing agar. ### Claim 25 (depends on 1, 9) A method for preparing a culture medium for the growth of a biologically pure culture of magnetic bacteria, comprising mixing together the ingredients of claim 1, 9, or 17, adjusting the pH of the mixture within the range of about 5.2-7.5, and sterilizing the mixture. ### Claim 26 (depends on 25) A method for preparing a culture medium in accordance with claim 25 wherein the pH is adjusted to about 6.7. ### Claim 27 (depends on 25) A method for preparing a culture medium in accordance with claim 25 wherein the mixture is sterilized by boiling or autoclaving.