School of Energy Science and Engineering, Indian Institute of Technology Guwahati, Guwahati, 781039, India.
School of Energy Science and Engineering, Indian Institute of Technology Guwahati, Guwahati, 781039, India; Department of Chemical Engineering, Indian Institute of Technology Guwahati, Guwahati, 781039, India.
J Environ Manage. 2022 Feb 15;304:114213. doi: 10.1016/j.jenvman.2021.114213. Epub 2021 Dec 9.
The utilization of costly chemical fertilizers and large freshwater requirements make the microalgae cultivation process uneconomical and highly unsustainable. To address this challenge, the present study aimed to integrate cattle wastewater (CW) (alternate for fertilizers) with domestic sewage wastewater (DSW) (substitute for freshwater) to cultivate Chlorella thermophile. To maximize the biomass yield, in-depth nutrient consumption patterns in both batch and fed-batch cultivation conditions were analyzed. Out of the eight (1%-4.5%) different CW feed concentrations tested during the batch cultivation, 2.5% CW set gave the highest biomass yield (2.17 g L), which was almost double the yield obtained using Bold Basal Medium (1.24 g L) and DSW without any CW addition (1.22 g L). However, the biomass yield declined with CW> 2.5%, and the ammonium (NH) inhibitory effect was observed. To address the (NH) toxicity challenge and further enhance the biomass yield, fed-batch experiments were designed with an intermittent CW feeding based on nutrient (NH) consumption pattern. The fed-batch cultivation resulted in twofold increased biomass yield (4.52 g L) in comparison to the batch process. The nutrient consumption pattern inferred that the (NH) concentration greater than 600 mg L during the logarithmic phase was inhibitory for Chlorella thermophila cells. On biomass characterization, a significant improvement in protein content with CW addition was observed. The FAME analysis of the derived lipid stated its competitive biofuel quality with up-gradation of C:16 and C:18 groups. Based on the obtained results, projection analysis for an integrated rural model demonstrated the technology's potential for sustainable water management with valuable resource recovery.
利用昂贵的化肥和大量淡水使微藻培养过程不经济且极不可持续。为了解决这一挑战，本研究旨在将牛废水（CW）（替代肥料）与生活污水（DSW）（替代淡水）集成，以培养嗜热绿藻。为了最大限度地提高生物量产量，分析了分批和补料分批培养条件下的深入营养消耗模式。在分批培养中测试了 8 种（1%-4.5%）不同的 CW 饲料浓度，2.5%的 CW 饲料浓度产生的生物量最高（2.17 g/L），几乎是使用 Bold 基础培养基（1.24 g/L）和不添加任何 CW 的 DSW（1.22 g/L）的两倍。然而，当 CW 浓度>2.5%时，生物量产量下降，并且观察到铵（NH）抑制作用。为了解决（NH）毒性挑战并进一步提高生物量产量，根据营养（NH）消耗模式设计了补料分批实验，采用间歇式 CW 进料。与分批过程相比，补料分批培养使生物量产量增加了两倍（4.52 g/L）。营养消耗模式推断，对数期 NH 浓度大于 600 mg/L 对嗜热绿藻细胞具有抑制作用。在生物量特性方面，观察到添加 CW 可显著提高蛋白质含量。衍生脂质的 FAME 分析表明，其具有竞争生物燃料质量，可提高 C:16 和 C:18 组的含量。根据获得的结果，对综合农村模型的预测分析表明，该技术具有可持续水管理和有价值资源回收的潜力。
