Effect of Nutrient and Hydrodynamic Conditions on Growth Characteristics of Photosynthetic Bacterial Biofilm / 中国生物工程杂志

ABSTRACT

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.