产油微藻自养培养条件调控

Optimization of the Major Culture Conditions of Autotrophic Microalgae for Lipid Production

摘要:

作为新兴生物燃料的生物柴油近年来发展迅速, 以微藻为代表的第二代生物能源是解决能源危机的长远之计, 但如何提高其产量仍是研究的热点问题。以提高产油自养微藻生物量和油脂含量为目的, 在气升式光反应器中运用均匀设计实验方法进行了条件优化试验。分别得出了氮原子浓度、通气速率、二氧化碳体积浓度和光照强度4个因素对小球藻C2生物量积累和油脂含量影响的显著回归方程和反应器优化培养条件。以生物量为指标的优化培养条件是: 氮原子浓度0.178 g/L, 通气速率5 L/min, 二氧化碳体积浓度3% (V/V), 光照强度6000 lx。该优化条件下, 生物量为2.11 g/L, 即生产速率为0.352 g/(L·d), 比测试实验中检测到的最高生物量[1.88 g/L, 即生产速率为0.313 g/(L·d)]提高了12.2%; 以油脂含量为指标的优化培养条件是: 进气速率0.400 L/min, 二氧化碳体积浓度1.94% (V/V), 得到油脂含量为22.4%, 比测试实验中检测到的最高油脂量(20.7%)提高7.7%。

Abstract:

Biodiesel, as a new form of bio-fuel, has developed greatly in recent years. The second generation of bio-energy represented by the lipid from microalgae is one of the long-term strategies to solve energy crisis in the future. However, improving its productivity is still the hotpot in recent years. The aim of this work was to improve the biomass and lipid content of autotrophic microalgae. In this study, we used uniform design to optimize the major culture conditions of autotrophic microalgae in the air-lift bioreactor. The significant regression equations which showed the effects of these conditions on biomass and lipid content of Chlorella C2 were concluded, respectively. According to the significant regression equations, the optimized culture conditions of biomass were: 0.178 g/L the concentration of N5+, 5 L/min air rate, 3% (V/V) CO2 and 6000 lx light intensity. The biomass and productivity attained were 2.11 g/L and 0.352 g/(L·d), 12.2% higher than the highest biomass and productivity obtained [1.88 g/L and 0.313 g/(L·d)] in those experiments. The optimized culture conditions of lipid content were: 0.400 L/min air rate and 1.94% (V/V) CO2. Lipid content attained from the optimized culture condition was 22.4%, 7.7% higher than the highest lipid content (20.7%) obtained in those experiments.