Abstract: An algae culture method capable of efficiently producing an osmotic pressure adjusting substance, a production method of the substance, and an algae culture method for recovering carbon dioxide from a mixed gas containing carbon dioxide and sulfurous acid gas. The methods involve preparing a plurality of enrichment cultures each containing betaine by culturing a culture of microalgae derived from an environmental specimen under a photoautotrophic condition and under a plurality of culture conditions; making a cultivation plan in which an optimum enrichment culture suitable for a main culture is selected from the plurality of enrichment cultures; producing a main culture that contains betaine under the photoautotrophic condition and a salt concentration of 10 wt. % or more; and separating betaine. In the main culture, the algae containing betaine are cultured while the mixed gas containing sulfurous acid gas and carbon dioxide is blown to a culture solution of the algae.

Abstract: An algae culture method capable of efficiently producing an osmotic pressure adjusting substance, a production method of the substance, and an algae culture method for recovering carbon dioxide from a mixed gas containing carbon dioxide and sulfurous acid gas. The methods involve preparing a plurality of enrichment cultures each containing betaine by culturing a culture of microalgae derived from an environmental specimen under a photoautotrophic condition and under a plurality of culture conditions; making a cultivation plan in which an optimum enrichment culture suitable for a main culture is selected from the plurality of enrichment cultures; producing a main culture that contains betaine under the photoautotrophic condition and a salt concentration of 10 wt. % or more; and separating betaine. In the main culture, the algae containing betaine are cultured while the mixed gas containing sulfurous acid gas and carbon dioxide is blown to a culture solution of the algae.