Utilization of the bio-hydrogen from the organic waste has the advantage of producing the biomass energy and treatment of the organic waste. In this paper, the outline of the possibility of the bio-hydrogen by using the rice rhizosphere bacteria is described.

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A hydroponic culture system was developed for producing garlic and for determining ajoene concentration and compared with those of garlic plants grown in a soil culture system. Garlic plants were grown in the hydroponic culture and the soil culture in a growth chamber under an artificial lighting at photosynthetic photon flux density of 450 μmol m^-2 s^-1 during the 12-h photoperiod with white fluorescent lamps, air temperatures of 25/21°C (light/dark), relative humidity of 75/90% (light/dark). Plants were grown on styrofoam boards and hanging in containers filled with nutrient solution in the hydroponic culture and on commercial soil filled in containers in the soil culture. Ajoene content in each plant part was determined after heated in rice oil. Average fresh weights of newly developed bulbs, roots and leaves in the hydroponic culture were 22.1, 65.8 and 36.5 g/plant, respectively, and was 3.5, 3.1 and 2.3 times, respectively, greater than those in the soil culture two months after planting. Ajoene contents in bulbs, roots and leaves in the hydroponic culture were 14.4, 11.6 and 7.8 mg/plant, respectively, and 4.1, 4.1 and 2.7 times, respectively higher than those in the soil culture. Garlic plants grown in the hydroponic culture were vigorous and healthy.

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Carp (Cyprinus carpio) (686±153 g) were exposed to acid /aluminum (pH 4.2, 0.8 ppm Al) artificial fresh water at 25°C for 48 hours. From the same individual, 0.5 ml arterial blood was sampled at a time from the dorsal aorta through a cannula before one hour and after 48 hours of exposure. Blood pH (BpH), hematocrit value (Hct), hemoglobin (Hb), blood oxygen content (CaO₂), blood oxygen partial pressure (PaO₂), blood oxygen saturation (SaO₂), blood total carbon dioxide (TaCO₂), blood carbon dioxide partial pressure (PaCO₂), total plasma protein (TPr), plasma sodium ion (Na⁺), plasma potassium ion (K⁺), plasma chloride ion (Cl^-), plasma calcium ion (Ca²⁺), and blood moisture content (Bm) were measured immediately after blood sampling. After 48 hours of exposure, BpH, Na⁺, Cl^-, PaO₂, SaO₂, and Bm decreased significantly, whereas PaCO₂, Hct, Hb, TPr, and Ca²⁺ increased significantly. CaO₂, TaCO₂, and K⁺ were not affected by 48 hours of exposure. All fish were not died within 48 hours of exposure, however, the fish blood homeostasis was most probably negatively affected by the acid/aluminum exposure.

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A 154-day experiment was conducted to investigate the effect of tank sizes on the growth performance and fin damage for individual rearing of tilapia Oreochromis niloticus. Tilapia (average weight: 9.0 ± 0.6 g) were stocked individually in custom made cartridge tank of three different sizes, L-size tank: 195×145×140, M-size tank: 150×115×105, S-size tank: 105×75×70 (length×width×depth (mm)), and fed commercial extruded pellets. Fifteen fish were stocked in a 30 L water volume aquarium and reared as the control. The fish growth in S-size tank was comparable to the control during initial 14 days and lowered thereafter. Growth reduction was found after 91 days for fish reared in M-size tank. While, fish reared in L-size grew successfully and comparable to the control throughout the rearing period. The growth reduction in S and M-size tanks appeared when body length/ tank length ratio (relative value) was more than 74.4 and 86.6%, respectively. Body width, pectoral fin length and ventral fin height of the fish reared in cartridge tanks were significantly greater than those of the control (P < 0.05) at the 91 days. Fish reared in cartridge tanks had less fin damages than fish for the control tank. The result suggests that tilapia grow successfully in cartridge type tanks under controlling relative value at less than 70–90% without fin injuring and deterioration of fish quality.

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