Abstract

Microalgae consists a promising feedstock for biofuel production due to their high growth rates and lipid content. Microalgal wastewater remediation can achieve both organic matters removal and biodiesel production, leading to economic benefits. In this study, immobilized microalgae and algae-bacteria consortia were used to treat synthetic fracturing wastewater. Organic matter removal, biomass production and lipid synthesis by co-culture of Chlorella vulgaris and Bacillus bacteria were investigated in comparison with an algae immobilization system during the process. The chemical oxygen demand removal rate and lipid concentration of the co-culture were both lower than those of the immobilized C. vulgaris, while algal biomass under the two cultivation conditions was similar. The immobilized algae provided higher amount of fatty acids, especially mono-unsaturated fatty acids, than the algae-bacteria consortia. Most of the fuel properties of biodiesel produced in both immobilized and co-cultured C. vulgaris complied with the specifications for standard biodiesel. The comparative results of enzyme activity showed that immobilization can enhance the activity of acetyl-CoA carboxylase, the key enzyme for fatty acids synthesis, leading to the formation of more fatty acids and lipids. Furthermore, immobilization decreased the ADP-glucose pyrophosphorylase activity and inhibited starch formation. Immobilization favors lipid production and removal of organics by C. vulgaris.

Graphic Abstract

中文翻译：

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小球藻的比较处理效率和脂肪酸合成：固定化与共培养

摘要

微藻由于其高的生长速率和脂质含量而成为一种有前途的生物燃料生产原料。微藻废水的修复可以实现有机物的去除和生物柴油的生产，从而带来经济利益。在这项研究中，固定化微藻和藻-细菌联合体被用于处理合成压裂废水。与藻类固定系统相比，研究了小球藻和芽孢杆菌细菌共培养过程中有机物的去除，生物量的产生和脂质的合成。共培养的化学需氧量去除率和脂质浓度均低于固定化寻常型梭状芽胞杆菌。，而两种培养条件下的藻类生物量相似。固定的藻类比藻类细菌联盟提供了更多的脂肪酸，尤其是单不饱和脂肪酸。在固定和共培养的普通梭菌中生产的生物柴油的大多数燃料特性均符合标准生物柴油的规格。酶活性的比较结果表明，固定化可以增强乙酰辅酶A羧化酶的活性，该酶是脂肪酸合成的关键酶，导致形成更多的脂肪酸和脂质。此外，固定化降低了ADP-葡萄糖焦磷酸化酶的活性并抑制了淀粉的形成。固定化有助于脂质产生和去除寻常念珠菌。

图形摘要