Luo Xiaoying, Chen Junhui, Wei Dong
School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, Guangdong, China.
Sheng Wu Gong Cheng Xue Bao. 2020 Jun 25;36(6):1150-1161. doi: 10.13345/j.cjb.190358.
The aim of this study was to establish a novel technology using microalgae for NO₃⁻ removal from high concentration wastewater and conversion to algal proteins. The effects of cultivation modes and illumination modes on the biomass yield, NO₃⁻ assimilation rate and algal protein yield were first investigated in shaking flasks for mixotrophic cultivation of Chlorella pyrenoidosa, and subsequently the scale-up verification in 5-L photo fermenter was successfully conducted. Fed-batch cultivation without medium recycling was the best cultivation mode in shaking flask system, in which the highest biomass yield (35.95 g/L), the average NO₃⁻ assimilation rate (2.06 g/(L·d)) and algal protein content (up to 42.44% of dry weight) were achieved. By using a staged increase of light intensity as illumination modes, the specific growth rate of cells could be significantly promoted to the highest (0.65 d⁻¹). After a 128-hour continuous cultivation in a 5-L photo fermenter, the highest biomass yield and the average NO₃⁻ assimilation rate were reached to 66.22 g/L and 4.38 g/(L·d) respectively, with the highest algal protein content at 47.13% of dry weight. Our study could provide a photo fermentation technology of microalgae for highly efficient treatment of waste industrial nitric acid and/or high concentration nitrate wastewater. This microalgae-based bioconversion process could coproduce protein-rich microalgal biomass, which facilitates the resource utilization of these type wastewater by trash-to-treasure conversion.
本研究的目的是建立一种利用微藻从高浓度废水中去除NO₃⁻并转化为藻类蛋白质的新技术。首先在摇瓶中对小球藻进行混合营养培养，研究培养模式和光照模式对生物量产量、NO₃⁻同化率和藻类蛋白质产量的影响，随后在5-L光生物反应器中成功进行了放大验证。在摇瓶系统中，不进行培养基循环的分批补料培养是最佳培养模式，在此模式下可实现最高生物量产量（35.95 g/L）、平均NO₃⁻同化率（2.06 g/(L·d)）和藻类蛋白质含量（高达干重的42.44%）。通过采用光照强度分阶段增加的光照模式，细胞的比生长速率可显著提高至最高（0.65 d⁻¹）。在5-L光生物反应器中进行128小时连续培养后，最高生物量产量和平均NO₃⁻同化率分别达到66.22 g/L和4.38 g/(L·d)，最高藻类蛋白质含量为干重的47.13%。我们的研究可为高效处理工业废硝酸和/或高浓度硝酸盐废水提供一种微藻光发酵技术。这种基于微藻的生物转化过程可以联产富含蛋白质的微藻生物质，通过变废为宝促进这类废水的资源利用。
