TECHNOLOGY FOCUS - BIOTECHNOLOGY - Preferred Method: The tissue and emitted heat amount of algae portion constituent of the microalgae are adjusted with control of environmental factor in any one of pH, illumination intensity, culture medium composition, dissolved oxygen concentration, external temperature, water temperature and carbon dioxide concentration. The method involves monitoring component of fats and oils, protein and carbohydrate in the algae portion of the microalgae. The nutritive salts are obtained from organic waste water generated from the digestive liquid, factory or treatment facility, which is a product of anaerobic fermentation. The method involves controlling the environmental factor of anaerobic fermentation using carbon dioxide separated from biogas. The anaerobic fermentation is performed with hydrological retention period of 30 days or less at medium temperature conditions of 33-37 degrees C or high temperature conditions of 50-57 degrees C. The contact opportunity of anaerobic bacteria and microalgae is increased by stirring inside the fermenter. The method involves solubilizing decomposition resistant components such as cell wall in the substrate. The method improves biodegradability by preprocessing the waste using any one of refinement by mechanical pulverizing and stirring process, where the stirring process is performed by cavitation effect, ultrasonic wave, hydrothermal reaction and hydroxyl radical. The method involves monitoring archaea number and bacterium number calculated from DNA per unit volume of sample which extracts the fermented liquor, and controlling the fermentation conditions. The method involves improving concentration of methane gas by performing at least one of process chosen from removal of components other than methane gas in the biogas by desulfurization of biogas, removal of water content by mist separator, high voltage water washing, film process, and pressure swing adsorption (PSA) process. EXAMPLE - No suitable example given.