We characterized the effects of different light qualities on the growth and antioxidant capacity of leaf lettuce grown in our plant factory. Antioxidant capacity was measured using the oxygen radical absorbance capacity (ORAC) assay because of its high reliability. Four sections of the plant factory were irradiated with light-emitting diodes (LEDs) at different red to blue light ratios: R100 section (100% red light), R90B10 section (90% red and 10% blue), R70B30 section (70% red and 30% blue), and R50B50 section (50% red and 50% blue). Another section was irradiated with fluorescent light. Photon flux density was adjusted to 200 µmol m^-2 s^-1. Leaf lettuces planted in each section were allowed to grow for 3 weeks. The hydrophilic oxygen radical absorbance capacity value for leaf lettuces grown in the R50B50 section was 3.6-4.8 times for leaf lettuces grown in the R100 section. Antioxidant capacity increased with increasing proportion of blue light, but growth rate decreased. Another experiment was performed in which leaf lettuces were grown with a reduced blue-light illumination period. Under these conditions (Ex-II-i), the fresh weight and antioxidant capacity of the leaf lettuce were improved by 1.3 times and 1.9 times, compared with those of lettuce grown in the R50B50 section for 3 weeks. Our results demonstrated that controlling the light environment can improve the growth rate and antioxidant capacity of leaf lettuce.

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In order to determine the suitable combination of concentrations of digestate from methane fermentation sludge and pH levels for culturing microalgae, Euglena gracilis was cultured in an aqueous solution containing digestate at 5, 10, 20, 25, 40 and 100% concentrations and at pH 3.4, 6.8, and 8.7. The pH of the aqueous digestate solution was adjusted with 10% HCl solution. Photosynthetic photon flux density (PPFD) was 150 µmol m^-2 s^-1 with continuous illumination at 30℃. The number of cells was monitored daily and specific growth rate (µ) was calculated. The highest µ (0.05 h^-1) was obtained at pH 3.4 in 20 – 25% digestate concentrations. This result demonstrates that E. gracilis could be produced at a high growth rate with diluted methane fermentation sludge adjusted to a low pH.

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In order to solve the problems of global environment, it is necessary for everyone to recognize the problems with awareness and participate in the environment protection with a cooperative activity. Environmental protection activity can be improved by utilizing the experiences obtained from our daily life and by comparing the domestic current situation with other countries at an objective viewpoint. Here we report the people's awareness and cooperative activity for environment protection in Edinburgh city (UK) and Tsukuba city (Japan). Public transportation in Edinburgh city is more developed than that in Tsukuba city which contributes to the lower emission of CO₂. Questionnaire regarding global environmental issue was conducted among 10 people in each city, respectively. All responders in Edinburgh are concerned with environmental issues while 80% of the responders in Tsukuba showed their concern with the same issue. It can be concluded that people in Edinburgh may have higher environmental awareness than people in Tsukuba. *This study was supported by research exchange project of University of Tsukuba. Finally, the importance of global education project for students will be discussed.

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