Photobioreactor cell culture systems, methods for preconditioning photosynthetic organisms, and cultures of photosynthetic organisms produced thereby
Certain embodiments of the invention involve methods and systems for preselecting, adapting, and preconditioning one or more species of photosynthetic organisms, such as algae, to specific environmental and/or operating conditions to which the photosynthetic organisms will subsequently be exposed during utilization in a photobioreactor apparatus of a gas treatment system. Also disclosed are new algal strains and cultures that can be produced by practicing the preselection, adaption, and preconditioning methods.
1. A method comprising acts of:
exposing a liquid medium comprising at least one species of photosynthetic organisms therein to a defined set of growth conditions, which are selected to simulate conditions to which the photosynthetic organisms will subsequently be exposed in a photobioreactor, to precondition the photosynthetic organisms to the defined set of growth conditions, the step of exposing being performed over a period sufficient for the photosynthetic organisms to undergo multiple generational natural selection and adaptation;
harvesting photosynthetic organisms preconditioned in the exposing step; and
inoculating a photobioreactor with at least a portion of the harvested photosynthetic organisms.
2. A method as recited in claim 1 , wherein the exposing act is performed utilizing an automated cell culture and testing system comprising at least one culture chamber comprising a photobioreactor having an internal volume between about 1 microliter and about 1 liter.
3. A method as recited in claim 2 , wherein the automated cell culture and testing system comprises a source of artificial light capable of driving photosynthesis configured and positioned to direct light to an inner volume of the cell culture chamber; and a light source modulator that is constructed and arranged to vary the intensity of the artificial light between a first intensity to a second intensity at a frequency of at least one variation per second.
4. A method as recited in claim 1 , wherein the predetermined set of growth conditions that are selected to simulate conditions to which the photosynthetic organisms will subsequently be exposed in the photobioreactor include at least one of liquid medium composition, liquid medium temperature, liquid medium temperature fluctuation magnitude, frequency, and interval, pH, light intensity, light and dark exposure intervals, feed gas composition, and/or feed gas temperature.
5. A method as recited in claim 4 , wherein in the exposing act, the liquid medium comprising the at least one species of photosynthetic organisms therein is exposed to the defined set of growth conditions that comprises variation of light intensity to cause photomodulation at a light/dark cycling frequency of at least one light/dark transition per minute.
6. A method as recited in claim 5 , wherein in the exposing act, the liquid medium comprising the at least one species of photosynthetic organisms therein is exposed to the defined set of growth conditions that comprises variation of light intensity to cause photomodulation at a light/dark cycling frequency of at least one light/dark transition per 30 seconds.
7. A method as recited in claim 6 , wherein in the exposing act, the liquid medium comprising the at least one species of photosynthetic organisms therein is exposed to the defined set of growth conditions that comprises variation of light intensity to cause photomodulation at a light/dark cycling frequency of at least one light/dark transition per 10 seconds.
8. A method as recited in claim 7 , wherein in the exposing act, the liquid medium comprising the at least one species of photosynthetic organisms therein is exposed to the defined set of growth conditions that comprises variation of light intensity to cause photomodulation at a light/dark cycling frequency of at least one light/dark transition per 5 seconds.
9. A method as recited in claim 8 , wherein in the exposing act, the liquid medium comprising the at least one species of photosynthetic organisms therein is exposed to the defined set of growth conditions that comprises variation of light intensity to cause photomodulation at a light/dark cycling frequency of at least one light/dark transition per second.
10. A method as recited in claim 9 , wherein in the exposing act, the liquid medium comprising the at least one species of photosynthetic organisms therein is exposed to the defined set of growth conditions that comprises variation of light intensity to cause photomodulation at a light/dark cycling frequency of at least one light/dark transition per ½ second.
11. A method as recited in claim 10 , wherein in the exposing act, the liquid medium comprising the at least one species of photosynthetic organisms therein is exposed to the defined set of growth conditions that comprises variation of light intensity to cause photomodulation at a light/dark cycling frequency of at least one light/dark transition per 1/10 second.
12. A method as recited in claim 11 , wherein in the exposing act, the liquid medium comprising the at least one species of photosynthetic organisms therein is exposed to the defined set of growth conditions that comprises variation of light intensity to cause photomodulation at a light/dark cycling frequency of at least one light/dark transition per 1/100 second.
13. A method as recited in claim 12 , wherein in the exposing act, the liquid medium comprising the at least one species of photosynthetic organisms therein is exposed to the defined set of growth conditions that comprises variation of light intensity to cause photomodulation at a light/dark cycling frequency of at least one light/dark transition per millisecond.
14. A method as recited in claim 4 , wherein in the exposing act, the liquid medium comprising the at least one species of photosynthetic organisms therein is exposed to the defined set of growth conditions that comprises exposure of the at least one species of photosynthetic organisms to a source of light capable of driving photosynthesis incident upon at least a portion of the photosynthetic organisms at an intensity at least that known to be capable of causing a reduction in the growth rate of a starter culture via photoinhibition.
15. A method as recited in claim 4 , wherein in the exposing act, the liquid medium comprising the at least one species of photosynthetic organisms therein is exposed to the defined set of growth conditions that comprises exposure of the at least one species of photosynthetic organisms to a source of light capable of driving photosynthesis incident upon at least a portion of the photosynthetic organisms at an intensity at least twice that known to be capable of causing a reduction in the growth rate of an unadapted sample comprising the at least one species of photosynthetic organisms therein via photoinhibition.
16. A method as recited in claim 1 , further comprising exposing the harvested photosynthetic organisms in the photobioreactor to the defined set of growth conditions.
17. A method as recited in claim 1 , further comprising, before exposing the liquid medium to the defined set of growth conditions, successively exposing the liquid medium to growth conditions that increasingly approximate the defined set of growth conditions over multiple doubling times of the at least one species of photosynthetic organism.
18. A method as recited in claim 17 , wherein successively exposing the liquid medium to growth conditions that increasingly approximate the defined set of growth conditions includes only varying one growth condition at a time to approximate the defined set of growth conditions.
19. A method as recited in claim 1 , wherein the period exceeds five doubling times of the at least one species of photosynthetic organism.
20. A method as recited in claim 1 , wherein the period exceeds 100 doubling times of the at least one species of photosynthetic organism.
21. A method as recited in claim 1 , wherein the defined set of growth conditions includes a concentration of NO x .
22. A method as recited in claim 1 , wherein the defined set of growth conditions includes a concentration of SO x .
23. A method as recited in claim 1 , wherein the defined set of growth conditions includes a concentration of a heavy metal.