Influence of algae species, substrata and culture conditions on attached microalgal culture.

The objective of this study was to understand and optimize the formation of microalgae biofilms in specific culture conditions. Firstly, the adhesion of six freshwater algae species was compared. Chlorococcum sp. was selected because of the high adhesion biomass productivity (ABP) and adhesion rate achieved. Secondly, the adhesion of Chlorococcum sp. was compared with nine commonly used supporting materials, and glass fiber-reinforced plastic proved to be the optimal substrata. Thirdly, based on response surface methodology experiments, a second-order polynomial model was developed to examine the effect of culture period, initial total nitrogen concentration (ITNC) in manure wastewater, pH and culture volume of the growth chamber on the adhesion of Chlorococcum sp. using glass fiber-reinforced plastic. The experimental and modeling results showed that ITNC, pH and culture volume as well as the interactions between culture period and ITNC, culture period and culture volume were significant on ABP. Optimum culture conditions were predicted at a culture period of 11 days, ITNC of 70 mg L(-1), pH of 8 and culture volume of 340 mL, under which the predicted maximum ABP was 4.26 g m(-2) day(-1). The prediction was close to validation experimental results, indicating that the model could be used to guide and optimize the attached culture of Chlorococcum sp. using glass fiber-reinforced plastic.