The Study Of Thermal Effect On Hydrogen Production Of Photosynthetic Bacteria Cells

Thermogenesis of photosynthetic bacteria cells in the process of hydrogen production caused temperature changes of the system. The reactor has a temperature of photosynthetic stress and deformation, which will impact hydrogen production and hydrogen production rate. The most important effect is that when photosynthetic bacteria produce hydrogen, it also produces exothermic at the same time. The changes of enzyme activity have a direct impact on the efficiency of hydrogen production. So studying thermal effect of hydrogen production of photosynthetic bacteria is very important.This paper is based on research supported by the National Natural Science Foundation (No.50676029).It is mainly based on the principle of thermal effects and the characteristics of hydrogen production to research temperature changes, heat production rate and the capacity changes of hydrogen production. Furthermore, it revealed the influence of thermal effect on Hydrogenase activity and Nitrogenase activity. The results showed that:1. The changes of system temperature and heat production rate were obvious at different initial conditions. System temperature increased with hydrogen production .The rate of heat production increased and then decreased.2. Results on the influence of thermal effect on the ability of hydrogen production showed that: When the initial temperature was below 27℃, thermal effect improved hydrogen production ability of photosynthetic bacteria. However, when the temperature was higher than 27℃, it did not have any effect; Hydrogen production and hydrogen production rate showed an upward trend with light intensity increaseing from 500Lx to 3000Lx.When the inoculation was less than 20%, thermal effect was conducive to the improvement of hydrogen production capacity. But when the inoculation was more than 20%, it had lower hydrogen production capacity and a secondary phenomenon; the hydrogen production capacity of the same carbon system with thermal effect was greater than non-thermal effect in the system. Glucose was the best hydrogen production carbon. It had the best hydrogen production capacity when Glucose concentration is 3.0%; the thermal effect was conducive to the improvement of hydrogen production capacity when NH₄⁺ concentration was less than 0.6g/L. When NH₄⁺ concentration was 0.8 g/L, the thermal effect was not conducive to the improvement of hydrogen production capacity, but it was conducive to the growth of the bacteria.3. There was the positive correlation between Hydrogenase activity and Nitrogenase activity. When the initial temperature was 27℃, Hydrogenase and Nitrogenase were the most significant activity. In the 500³000Lx range, increased light intensity was conducive to improve Hydrogenase activity and Nitrogenase activity. Thermal effect could contribute to the improvement of the Nitrogenase activity and Hydrogenase activity when the inoculation increased 5% to 20%. There was non-hydrogen expression when glucose concentration was 0.5%. When Glucose concentration was the 3.0%, Hydrogenase activity and Nitrogenase activity was the highest, repectively at 495nmolC2H4/mL/h,925nmolH2/mL/h, followed by sugar, and then acetic acid and lactic acid. Thermal effect contributed to the activity with different NH₄⁺ concentration, and it had the most notable activity when NH₄⁺ concentration was 0.4g/L.4. Thermal effect had an important effect on improving the concentration of hydrogen. The more the temperature was increased, the higher concentration of hydrogen production.5. Glucose as carbon source, photosynthetic bacteria cells grew the fast, followed by sugar, and then acetic acid, and lactic acid is the minimum. When glucose concentration was 0.5%, photosynthetic bacteria cells didn't produce hydrogen but changed pigment, and absorption peaks didn't disappear with the time of the delay at 807 nm and 863 nm.