US3958364A
Expired / Lapsed
US
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Production of algal bio-polymers
Assignee: American Bioculture Inc
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Filing: 1975-05-05
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Granted: 1976-05-25
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Expires: 1995-05-05
Abstract
Abstract Cultivation of algae to produce long chain polymers having flocculating properties is disclosed. Algae are cultivated in an aqueous nutrient medium until relatively high culture densities are achieved and thereafter under conditions in which the cells become deficient in nitrogen thereby causing the cells to shift from a growth phase in which protein production predominates to a growth phase in which extracellular polymer production predominates. An adequate supply of other nutrients as well as CO2 and light are maintained in the culture medium during the latter phase to insure that a change in cell metabolism is produced by a deficiency in nitrogen. The algae then produce high molecular weight polymers exhibiting strong flocculating activity.
Inventors
- 👤 Paula Schenck
- 👤 Patricia L. Foster
- 👤 William W. Walker, Jr.
- 👤 Samuel Fogel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 08:59
CPC Classifications
C; C12; C12N; C12N1/00; C12N1/12; A; A01; A01G; A01G33/00; C02; C02F; C02F1/00; C02F1/52; C02F1/5236; C02F1/5263; C02F3/00; C02F3/32; C09; C09K; C09K23/00; C09K23/56; Y; Y02; Y02A; Y02A40/00; Y02A40/80; Y02W; Y02W10/00; Y02W10/30; Y02W10/37; Y02W10/40; Y10; Y10S; Y10S47/00; Y10S47/10
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
91 words
A method of producing biopolymers exhibiting flocculating activity comprising; cultivating algae in the presence of light and carbon dioxide in a nutrient medium suitable for expodential growth to a predetermined population density, thereafter restricting the available nitrogen and continuing to cultivate the algae while maintaining a supply of available phosphorus and other plant nutrients in the culture medium as required so that the nitrogen content of the cells drops to below about 5%, and after the cellular nitrogen is below 5% by weight, withdrawing active flocculating agent from the culture medium.
Claim 2
Independent Claim
91 words
A method of producing biopolymers exhibiting flocculating activity comprising; cultivating algae in the presence of light and carbon dioxide in a nutrient medium suitable for expodential growth to a predetermined population density, thereafter restricting the available nitrogen and continuing to cultivate the algae while maintaining a supply of available phosphorus and other plant nutrients in the culture medium as required so that the nitrogen content of the cells drops to below about 5%, and after the cellular nitrogen is below 5% by weight, withdrawing active flocculating agent from the culture medium.
Claim 3
Dependent Claim
23 words
A method according to claim 1 wherein the algae are selected from the group consisting of unicellular green and non-nitrogen fixing blue-green algae.
Claim 4
Dependent Claim
14 words
A method according to claim 2 wherein the algae is of the genus Chlorella.
Claim 5
Dependent Claim
16 words
A method according to claim 3, wherein the cellular phosphorus level is maintained above about 0.5%.
Claim 6
Dependent Claim
14 words
A method according to claim 2 wherein the algae is of the genus Chlamydomonas.
Claim 7
Dependent Claim
15 words
The method according to claim 5 wherein the algae is of the species Chlamydomonas mexicana.
Claim 8
Dependent Claim
23 words
A method according to claim 1 wherein the exposure to light is continuous when the algae are grown in the nitrogen restricted medium.
Claim 9
Independent Claim
97 words
A method of producing polymeric material having flocculating activity from algae, comprising the steps of culturing algae in a nutrient medium under conditions promoting optimum growth for a first period of time until a predetermined cell density is reached, thereafter culturing the algae for a second period of time, depriving the algae of available nitrogen during the second period of time to reduce the cellular nitrogen content to below about 5% by weight and maintaining light, CO 2 and plant nutrients other than nitrogen in quantities which are not growth limiting during the second period of time.
Claim 10
Independent Claim
97 words
A method of producing polymeric material having flocculating activity from algae, comprising the steps of culturing algae in a nutrient medium under conditions promoting optimum growth for a first period of time until a predetermined cell density is reached, thereafter culturing the algae for a second period of time, depriving the algae of available nitrogen during the second period of time to reduce the cellular nitrogen content to below about 5% by weight and maintaining light, CO 2 and plant nutrients other than nitrogen in quantities which are not growth limiting during the second period of time.
Claim 11
Independent Claim
131 words
A method of producing a flocculating agent which comprises culturing algae in a tank containing an aqueous nutrient medium having sufficient available nitrogen, other nutrients, and CO 2 in the presence of light, so as to foster exponential growth of the algae, then when a predetermined cell density is reached, transferring a portion of the algae and nutrient medium to a second tank, adding water to the second tank, in an amount proportional to the volume of algae and nutrient medium transferred to thereby reduce the percentage content of nitrogen in the medium, supplementing the second tank with plant nutrients other than nitrogen so that growth of the algae is not limited by such other nutrients and continuing the culturing in the second tank until a predetermined cell density is reached.
Claim 12
Independent Claim
131 words
A method of producing a flocculating agent which comprises culturing algae in a tank containing an aqueous nutrient medium having sufficient available nitrogen, other nutrients, and CO 2 in the presence of light, so as to foster exponential growth of the algae, then when a predetermined cell density is reached, transferring a portion of the algae and nutrient medium to a second tank, adding water to the second tank, in an amount proportional to the volume of algae and nutrient medium transferred to thereby reduce the percentage content of nitrogen in the medium, supplementing the second tank with plant nutrients other than nitrogen so that growth of the algae is not limited by such other nutrients and continuing the culturing in the second tank until a predetermined cell density is reached.
Claim 13
Dependent Claim
20 words
A method according to claim 9 wherein the second tank is substantially continuously exposed to light during the culturing step.
Claim 14
Dependent Claim
15 words
A method according to claim 9 wherein the alga is selected from the genus Chlamydomonas.
Claim 15
Dependent Claim
14 words
A method according to claim 11 wherein the alga is the species Chlamydomonas mexicana.
Claim 16
Independent Claim
73 words
A method of producing a flocculating agent comprising first cultivating algae in the presence of light and CO 2 in a nutrient medium favoring cell multiplication until a predetermined population density is reached, thereafter continuing to cultivate the algae in the presence of light and CO in a nutrient medium deficient in nitrogen but having other plant nutrients available in quantities which are not growth limiting thereby favoring the production of flocculating agent.
Claim 17
Independent Claim
73 words
A method of producing a flocculating agent comprising first cultivating algae in the presence of light and CO 2 in a nutrient medium favoring cell multiplication until a predetermined population density is reached, thereafter continuing to cultivate the algae in the presence of light and CO in a nutrient medium deficient in nitrogen but having other plant nutrients available in quantities which are not growth limiting thereby favoring the production of flocculating agent.
Claim 18
Independent Claim
90 words
A method of producing algal biopolymers having flocculating activity comprising, culturing algae in an aqueous nutrient medium rich in available nitrogen and other required plant nutrients under conditions which favor exponential growth of the algae until the culture reaches a predetermined density, thereafter continuing to culture the algae in a nutrient medium deficient in available nitrogen but having other plant nutrients in sufficient supply so that growth is not limited by the absence of such other nutrients until nitrogen content of the algal cells drops below about 5% by weight.
Claim 19
Independent Claim
90 words
A method of producing algal biopolymers having flocculating activity comprising, culturing algae in an aqueous nutrient medium rich in available nitrogen and other required plant nutrients under conditions which favor exponential growth of the algae until the culture reaches a predetermined density, thereafter continuing to culture the algae in a nutrient medium deficient in available nitrogen but having other plant nutrients in sufficient supply so that growth is not limited by the absence of such other nutrients until nitrogen content of the algal cells drops below about 5% by weight.
References Cited (Backward Citations)
US2732661A
Cited
US2908113A
Cited
US3197309A
Cited
US3546812A
Cited
US3732089A
Cited
US3820281A
Cited
US3879890A
Cited
US3889418A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-05-25 | 1979-11-24 | 1980-05-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-05-25 | 1983-11-24 | 1984-05-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-05-25 | 1987-11-24 | 1988-05-25 | $7700.00 | Window Closed / Lapsed |