不产氧光合细菌Rhodobacter sphaeroides产氢影响因子研究

Influence of factors on hydrogen production capability of Rhodobacter sphaeroides

对不产氧光合细菌球形红细菌Rhodobacter sphaeroides产氢的影响因子进行了初步研究。结果表明,处于不同生长期的球形红细菌接种后的产氢速率略有差异,稳定期的菌株的产氢能力相对较低。苹果酸钠、乳酸钠、丙酮酸钠和葡萄糖都是球形红细菌产氢的良好碳源,这表明球形红细菌具有利用食品工业等高浓度废水为底物产氢的可能性。以葡萄糖和谷氨酸钠为C源和N源产氢时,适宜的葡萄糖浓度在25～50mmol/L之间,谷氨酸钠浓度在2～10mmol/L之间。球形红细菌产氢的适宜pH值在7.0～8.0范围内,酸性环境明显不利于该菌的催化放氢,适宜的温度在30～35℃范围内。光照强度在5000～7000lx之间适合于产氢。球形红细菌的固氮酶活性和放氢活性之间呈正相关性。吸氢酶虽然可在无固氮酶和无放氢活性的状态下独立表达,但多数情况下仍受氢气浓度的调节。以氮气为氮源时,固氮酶活性和放氢活性较低,铵的浓度高于0.5mmol/L时,固氮酶活性完全受到抑制,进而抑制产氢。

Experiments were conducted to present the influence of factors on hydrogen production capability of Rhodobacter sphaeroides. The results showed that the different growth phases of seed culture affected hydrogen production activity to a little extent, and the hydrogen production activity of the seed culture in stable growth phase was slightly lower than that in exponential phase. Malate, lactate, pyruvate and glucose were all good substrates for Rhodobacter sphaeroides to produce hydrogen. This indicated the possibility of Rhodobacter sphaeroides for producing hydrogen by using wastewater from food industry. When glucose and sodium glutamate were used as carbon source and nitrogen source for hydrogen production, the optimal concentrations of glucose were 25--50mmol/L, and that of sodium glutamate were 2-10mmol/L. The optimal pH was between 7.0 and 8.0, and the acidic environment was evidently disadvantage for hydrogen production. The optimal temperature was between 30℃ and 35℃ and the optimal light intensity ranges from 5000 Ix to 7000 Ix. As the nitrogenase activity increased, the hydrogen production activity increased accordingly. Besides, the ability of hydrogenase might be affected by the concentration of hydrogen. The nitrogenase activity and the hydrogen production activity were limited to a low level when the gas of nitrogen was used as the nitrogen source. The nitrogenase activity and the hydrogen production ability were significantly inhibited by the presence of NH4^ ＋ at the concentration of 0.5mmol/L or a higher value.