Abstract:

Achieving largescale cultivation of microalgae and accessing effectively to the target product are the significant foundation for suitable culture conditions. But it lacks the strategy on absorption and utilization of nitrogen and phosphorus for largescale breeding of Chlorella. This study did experiment on the growth of Chlorella and the consumption of nitrogen, phosphorus under the condition of static culture, ventilation and aeration external carbon source culture, using fedbatch sampling methods on training process. The results showed that the pH of algal liquid slightly decreased and changed between 7 to 9. Absorption of Chlorella on nitrate was rapid at first and then slowed down. The solution of ventilation cultured and glucose plus nitrate nitrogen in the early and midexponential stage dropped to 32284 mg/L rapidly, but the consumption was slowed later. The nitrate of ventilation rapidly declined to 44510 mg/L in the exponential growth stage, and then tended to steady declined stage. The nitrate of static culture stage consumed slowly at first, and it decreased to 66605 mg/L rapidly, then the consumption was stable at the later stage. The absorption and utilization of Chlorella on phosphorus was rapid, leading to a rapid decline of phosphorus to 3948-8219 mg/L at first and then a relative stable concentration. Under the static culture conditions, the growth rate of Chlorella was influenced mainly by concentration of nitrate and level of pH. Under the conditions of ventilation, the growth rate of Chlorella was mainly affected by the concentration of nitrate. Under the condition of carbon culture, the growth rate of Chlorella was mainly colimited by the concentrations of phosphorus and nitrate. In the algae culture of ventilation and carbon source in fedbatch sampling optimization, the growth rate was affected slightly in the middle and the highest biomass was up to 3 565 mg/(L·d) per unit of time.