营养及水力条件影响光合细菌生物膜生长特性实验

对平板式生物膜反应器内，流量及底物浓度范围分别为37.8~1080ml/h、0.05~10g/L的不同生长条件下光合产氢细菌生物膜生长特性进行了实验研究，讨论了不同水力及营养条件对沼泽红假单胞菌生物膜表面覆盖率、膜厚、干重和密度的影响。实验结果表明，不同水力及营养条件对生物膜生长速率及结构具有重要影响。在相同的时间间隔内，在高流速条件下光合细菌菌落生长较快，但过高的液体流速会导致部分生物膜脱落；高流速条件易使生物膜形成薄而致密的结构。光合细菌生物膜在循环液底物浓度较高时生长较快，密度也最高；而贫营养条件可以促成结构疏松生物膜在固液界面的形成，这种生物膜结构有利于微生物在低底物浓度条件下底物在生物膜内的传输。

Effect of Nutrient and Hydrodynamic Conditions on Growth Characteristics of Photosynthetic Bacterial Biofilm

The growth characteristics of hydrogen-production photosynthetic bacterial biofilm in a plate-type biofilm bioreactor were studied experimentally. The effect of hydraulic and nutritional conditions on the surface coverage, thickness, dry weight, and density of Rhodoseudomonas palustris biofilm was observed, respectively. Glucose in the influent concentration range from 0.05 to 10 g/L was used as the sole carbon source. Liquid flow rate was varied from 37.8 to 1080ml/h in the experiments. Experimental results showed that the hydraulic and nutritional conditions had significant influences on the growth rate and structure of biofilm. In a lower flow rate range, high liquid flow rate was propitious to the diffusion of substrate from liquid phase to solid liquid interface, which resulted in the fast development of biofilm on the solid liquid interface. However, some parts of biofilm were scraped off when the flow rate exceeded a threshold. At a fixed liquid flow rate, the biofilm density increased with the increase in the substrate concentration. The biofilm having thick and loose structure was developed under low substrate concentration condition. The biofilm structure was convenient for the nutrient transfer in the biofilm, which is a survival strategy of microorganisms facing adverse circumstances.