底物初始浓度对光合细菌产氢动力学特性的影响

实验研究了底物初始浓度对光合细菌产氢动力学特性的影响，并对光合细菌产氢得率和初始底物转化为氢气得率进行比较，分析底物初始浓度对光合细菌产氢代谢的影响，实验发现底物初始浓度为120 mmol/L时最适合光合细菌的产氢代谢，底物初始浓度达到140 mmol/L时，光合细菌主要进行生物量合成和产酸代谢，得到各浓度梯度下的最大生物量，但对产氢代谢产生抑制作用，表明最大生物量与最大的产氢能力之间不成正比关系及光合细菌产生CO2机制与产氢机制不同；光合细菌最大比产氢活性表现在对数生长期，最大生物量出现在稳定期。实验证明，光合细菌对数生长期受底物浓度影响大，底物浓度低，最大生物量所对应的时间相对较早，底物浓度增大，最大生物量所对应的时间相对延后。

Effect of initial substrate concentration on dynamic characteristic of hydrogen production by photosynthetic bacteria

The effect of initial substrate concentration on the dynamic characteristics of hydrogen production by photosynthetic bacteria(PSB) was studied in the experiment,and metabolism of hydrogen production was analyzed by comparing the ratio between quantity of hydrogen produced and initial substrate quantity to that between quantity of hydrogen produced and quantity of consumed substrate.It was found that the optimal initial substrate concentration of hydrogen production by PSB was 120 mmol/L,when initial substrate concentration came to 140 mmol/L PSB would mostly synthesize biomass and acidic product,and the maximum biomass among all initial substrate concentrations was gained.However,the metabolism of hydrogen production was restrained.This indicated that there was no direct proportion between the maximum biomass and the maximum hydrogen production rate,and the mechanism of CO2 production was different from that of H2 production.Meanwhile,the maximum specific ratio of hydrogen production of PSB was found in exponential phase,while maximum biomass was found in steady phase.On the other hand,the fact that initial substrate concentration influence obviously on exponential phase of PSB was found,when initial substrate concentration was smaller the maximum biomass was gained earlier,whereas the maximum biomass was gained latter when initial substrate concentration was bigger.