TECHNOLOGY FOCUS - BIOLOGY - Preferred Method: The level of carbonic acid in the carbonic acid-enriched growth medium is maintained at a steady level. The growth medium is enriched with carbonic acid by a step comprising feeding the photosynthetic plant or algal cell suspension culture with a carbonic acid solution, a solid or liquid precursor, or a gaseous mixture of atmospheric air and carbon dioxide. The carbonic acid is provided by feeding the photosynthetic plant or algal cell suspension culture with a gaseous mixture carbon dioxide and one or more other gases, having a carbon dioxide concentration of greater than 10%, preferably at or greater than 40%, e.g. up to 50%, 45% or 40%, where the carbon dioxide concentration is 30-45%, 35-45%, preferably 40% greater than or equal to 4, 3, 2 or 1%. The photosynthetic plant or algal cell suspension culture is fed with bubbles of a gaseous mixture of carbon dioxide and one or more other gases, where the size of the bubbles, path length of the bubbles though the growth medium and pressure of the growth medium are enrich the growth medium with carbonic acid, preferably to a concentration of carbonic acid. The carbonic acid is provided by feeding the photosynthetic plant or algal cell suspension culture with a gaseous mixture of carbon dioxide and one or more other gases, and the efficiency of absorption of the carbon dioxide component of the gaseous mixture by the photosynthetic plant or algal cell suspension culture is greater than 40%, preferably greater than 95% or more. The culture medium is maintained at a pH of less than 7, preferably 4.5-5.5, or up to 6.4. The carbonic acid is provided by feeding a gaseous mixture of atmospheric air and carbon dioxide to the photosynthetic plant or algal cell suspension culture medium, and the photosynthetic plant or algal cell suspension culture is maintained at an atmospheric pressure of at least, or greater than 1, preferably 3. In the method, at least 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% or substantially 100% of the photosynthetic product that is produced by photosynthetic plant or algal cell suspension culture, which is obtained from the enzymatic conversion of aqueous carbonic acid to the photosynthetic product. The culture is maintained in the presence of light comprising light at photosynthetically active radiation wavelengths of 450-750 nm, preferably 650 nm. The culture is maintained in the presence of substantially constant light. The pH of the photosynthetic plant or algal cell suspension culture is maintained at the selected pH using a buffering system. The method includes providing a carbonic acid-enriched growth medium. The method comprises the step of extracting or recovering the photosynthetic product from the photosynthetic plant or algal cell suspension culture medium. The step of extracting or recovering the photosynthetic product is a continuous process. The step of extracting the photosynthetic product prevents the level of the photosynthetic product accumulating in the medium of the photosynthetic plant or algal cell culture to a level that reduces or inhibits the production of further photosynthetic product, preferably such that the level of the photosynthetic product is prevented from accumulating above the level of 600 g/l, 500 g/l, 400 g/l, 300 g/l, 200 g/l, 100 g/l, 50 g/l or less. The method is used to provide a photosynthetic product in place of the use of the first cell suspension culture of photosynthetic plant cells in WO 2009/133351. The biological product is synthesized by the cells of the second cell culture. The cells of the first cell suspension culture and the cells of the second cell culture are mixed together and cultured in the same medium. The cells of the first cell suspension culture and the cells of the second suspension culture are cultured in separate culture vessels that are connected in fluid communication. The method-1 comprises the step of recovering or extracting photosynthetic product (such as sugar), or growth medium enriched with the photosynthetic product, from the culture medium of the first cell suspension culture and the further step of feeding the recovered or extracted photosynthetic product, or product-enriched growth medium, into the second cell culture. The step of recovering or extracting photosynthetic product (such as sugar) from the culture medium of the first cell suspension culture comprises separating the photosynthetic product-containing medium of the first cell culture from the cells present in it, e.g. by allowing the cells of the culture to settle to the bottom of the culture tank and then removing at least a portion of the photosynthetic product-containing growth medium from the tank. The step of recovering or extracting photosynthetic product (such as sugar) from the culture medium of the first cell suspension culture comprises separating the photosynthetic product-containing medium of the first cell culture from the cells present in it, e.g. by filtration, or continuously removing photosynthetic product from the cell culture medium of the first cell culture, e.g. by dialysis of the culture medium. The method-1 is a method for the production of at least one fatty acid and/or oil from a plant cell culture, the method comprising maintaining a second cell suspension culture of oil-producing plant cells in the presence of the photosynthetic product (such as sugar) generated by the first cell suspension culture and under conditions such that the cultured oil-producing plant cells produce at least one fatty acid and/or oil. The method-1 further comprises: the step of extracting the biological product from the second cell culture; and purifying and/or processing the thus-extracted biological product. The method-1 comprises the step of extracting the at least one fatty acid and/or oil from the second cell suspension culture of oil-producing plant cells. The steps of maintaining a second cell suspension culture of oil-producing plant cells in the presence of the photosynthetic product (such as sugar) generated by the first cell suspension culture and under conditions such that the cultured oil-producing plant cells produce at least one fatty acid and/or oil, and extracting the at least one fatty acid and/or oil from the second cell suspension culture of oil-producing plant cells, is performed in accordance with the method of WO 2009/133351, and preferably the second cell suspension culture of oil-producing plant cells is maintained at a pH less than pH 7, 6.5, 6 or 5.5, preferably greater than 4.5, or less than 5.5, such that the cultured cells of the second cell suspension culture of oil-producing plant cells synthesize and secrete at least one fatty acid and/or oil into the cell suspension culture medium. The fatty acid and/or oil that is extracted is then further processed to convert it to a biofuel, or is optionally further purified and/or used in a downstream process such as by incorporation into a food product, cosmetic, or lubricant. The first cell suspension culture, and optionally also the second cell culture, is/are maintained at the site of the carbon dioxide-producing process, such as at the site of a power generating facility, or at the site of a biofuel (such as bioethanol or other alcohol) generating facility, that generate carbon dioxide as a by-product. The carbon dioxide that is captured is the by-product of a carbon dioxide-producing process, such as a process of power generation that uses carbon fuels, or a process of biofuel (such as bioethanol or other alcohol) production by microorganisms (such as yeast) that releases carbon dioxide. The carbon dioxide is captured at the site of the carbon dioxide-producing process, such as at the site of a power generating facility, or at the site of a biofuel (such as bioethanol or other alcohol) generating facility, that generates carbon dioxide as a by-product. Preferred Components: The concentration of carbonic acid in the carbonic acid-enriched growth medium is 0.1-10 wt./vol.%. The partial pressure of carbon dioxide is greater than 10-8, preferably greater than 10-7, 10-6, 10-5, 10-4, such as within the 10-5 to 10-4. The amount of light energy (such as number of photons) required to enable the photosynthetic plant or algal cell suspension culture to photosynthetically produce 100 g of the photosynthetic product is less than 50%, 40%, 30%, 20%, 10%, 9%, 8%, 7%, 6%, or 5% of the amount of light energy (such as number of photons) required to enable the same photosynthetic plant or algal cell suspension culture to photosynthetically produce 100 g of the photosynthetic product when supplied with an equivalent volume and rate of atmospheric levels of gaseous carbon dioxide, and maintained at a physiological pH of 6.8-7.5, preferably 7.3. The buffer comprises citric acid and disodium hydrogen orthophosphate, or any other suitable buffering system to the plant or algal cells in culture. The photosynthetic cell suspension culture is a photosynthetic suspension culture of plant cells and contains no, or substantially no, algal cells. The photosynthetic plant cell is a differentiated photosynthetic plant cell, such as a cell that is specialized for photosynthesis, e.g. a cell from the leaf or green tissue of a plant, including a palisade, leaf mesoderm or petiole cell. The photosynthetic plant cell suspension culture is a suspension culture of plant palisade cells. The extracted or recovered photosynthetic product is provided in the form of a syrup, crystals, or solution. The volume of the photosynthetic plant or algal cell suspension culture is at least 10000 l, such as 20000 l, 30000 l, 40000 l, 50000 l, or more. The cells of the first cell suspension culture photosynthesize in the presence of light and carbon dioxide and/or carbonic acid. The cells of the first cell suspension culture and the cells of the second cell culture are in fluid communication with each other. The fluid communication between the cells of the first cell suspension culture and the cells of the second cell culture allows the photosynthetic product (such as sugar) released by the cells of the first cell suspension culture to be used as a carbon source by the cells of the second cell culture. The cells of the first cell suspension culture and the cells of the second cell culture are each grown in separate culture vessels that are not in fluid communication with each other. The second cell culture is maintained in the presence of photosynthetic product (such as sugar) generated by the first cell suspension culture at a sugar concentration of 20-400 g/l, such as up to 300 g/l, 200 g/l, 100 g/l, preferably 50 g/l. The cells of the second cell culture are prokaryotic or eukaryotic, such as bacterial, fungal, plant, animal or human cells. The cells of the second cell culture are microorganisms, such as yeast (e.g. a Saccharomyces sp.), and optionally the biological product is an alcohol, such as ethanol. The photosynthetic plant cells present in the first cell suspension culture possess one of more characteristics comprising: as a mean average over 100 randomly sampled cells from the first cell suspension culture, where the photosynthetic plant cells contain at least 10, 15, 30, 40, 50 or more chloroplasts per cell; a higher chlorophyll content (preferably 2-, 3-, 4-, 5-, 10-, 20-fold or more) than cells of a mesoderm cell suspension culture derived from the same plant species, e.g. as determined by a spectrophotometric assay which compares the absorbance of a test sample at a wavelength of 594 nm (which indicates chlorophyll content) to the absorbance of the same sample at a wavelength of 1500 nm (which indicates cell density) such that chlorophyll content can be represented by the ratio of Abs594:Abs1500; the ability to produce at least 30, 40, 50 or more g/l of sugar (such as glucose, sucrose and/or fructose) when maintained in cell suspension culture for a week at 20-24 degrees C, under atmospheric pressure, in the presence of excess carbon dioxide, and with exposure to full spectrum light, with intensity at 594 nm of 15.12x 10-3 watts; and/or the ability to capture at least 50, 75, 100 mg or more of carbon, per 100 g dry weight cells, per hour, when maintained in cell suspension culture at 20-24 degrees C, under atmospheric pressure, in the presence of excess carbon dioxide, and with exposure to full spectrum light, with intensity at 594 nm of 15.12x 10-3 watts. The photosynthetic plant cells present in the first cell suspension culture of are isolated from a copper-tolerant plant, such as from Agrostis tenuis. The first cell suspension culture of photosynthetic plant cells has a cell culture medium copper level of up to 0.1 M, e.g. greater than 0.01 M, 0.1 M or 0.5 M. The oil-producing plant cell present in the second cell suspension culture is a differentiated plant cell. The differentiated plant cell is a cell that is specialized in the production and storage of oils, such as a mesoderm cell. The first cell suspension culture of photosynthetic plant cells is fed carbon dioxide from a carbon dioxide source liquid carbon dioxide or gaseous carbon dioxide and/or is fed carbonic acid by a step comprising feeding the photosynthetic plant cell suspension culture with a carbonic acid solution, a solid or liquid precursor, or a gaseous mixture of carbon dioxide and one or more other gases. The liquid or gaseous carbon dioxide source, the carbonic acid solution, the solid or liquid precursor of the carbonic acid solution, or the gaseous mixture of carbon dioxide and one or more other gases is obtained as a by-product of a carbon dioxide-producing process, such as a process of power generation that uses carbon fuels, or a process of biofuel (such as bioethanol or other alcohol) production by microorganisms (such as yeast) that releases carbon dioxide. The two-culture system further comprises a carbon dioxide generating source, where the generated carbon dioxide is fed into the first cell suspension culture and/or used to produce carbonic acid solution, a solid or liquid precursor of a carbonic acid solution, or a gaseous mixture of carbon dioxide and one or more other gases, which is fed into the first cell suspension culture. The carbon dioxide capture system comprises: a carbon dioxide generating source; and a second plant cell suspension culture of oil-producing plant cells. The two-culture system or the carbon dioxide capture system produces at least one fatty acid and/or oil from the capture carbon dioxide and the thus produced at least one fatty acid and/or oil are used to supplement the fuel used by the power generating facility. In the generating facility, sugars produced by the first cell suspension culture of photosynthetic cells present within the two-culture system or the carbon dioxide capture system are used to supplement the growth of microorganisms (such as yeast) used in the production of biofuel by the biofuel generating facility. EXAMPLE - No suitable example given.