基于无机氮磷利用特征的小球藻优化培养技术

OPTIMIZED CULTURE CONDITIONS FOR CHLORELLASP.BASED ON NITROGEN AND PHOSPHORUS ABSORPTION KINETICS

氮磷对小球藻的生长产生重要影响,基于氮磷优化培养条件的探讨具有理论和实际意义。在静置培养、通气培养和通气加碳源(葡萄糖)培养等条件下对小球藻的生长影响和氮磷消耗进行了试验,采用分批取样补料方式对培养过程进行了优化研究。结果表明,在未调节培养液pH值条件下,藻液的pH值在7~9变化,随培养时间呈略微下降的趋势。各培养条件下,小球藻对硝酸盐的吸收速率均表现出先快后慢的特征,对磷的吸收利用表现为总磷先快速被吸收利用,然后稳定在一定范围内波动。小球藻的生长在静置培养条件下主要受培养液中硝酸盐氮含量和培养液pH值的影响,通气培养条件下主要受培养液中硝酸盐氮含量的影响,通气外加碳源培养条件下主要受培养液中可溶解性总磷含量和硝酸盐氮含量双重影响。在通气外加碳源分批取样补料的藻类优化培养中,生长中期取样补料小球藻生长速率受影响较小,单位时间生物量最高,达3 565mg/(L·d)。

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.