Laboratory of Biochemical Engineering & Environmental Technology (LBEET), Department of Chemical Engineering, University of Patras, 26504 Patras, Greece.
Centre de Développement des Energies Renouvelables (CDER), BP. 62, Route de l'Observatoire, Algiers 16340, Algeria.
Mar Drugs. 2022 Jun 25;20(7):415. doi: 10.3390/md20070415.
Microalgae have been recently recognized as a promising alternative for the effective treatment of anaerobic digestion effluents. However, to date, a widely applied microalgae-based process is still absent, due to several constraints mainly attributed to high ammonia concentrations and turbidity, both hindering microalgal growth. Within this scope, the purpose of the present study was to investigate the performance of two strains, SAG 211-11b and a local Algerian isolate, under different nitrogen levels, upon ammonia stripping. The experiments were performed on cylindrical photobioreactors under controlled pH (7.8 ± 0.2) and temperature (25 ± 2 °C). Cultures were monitored for biomass production and substrate consumption. After sampling at the beginning of the stationary phase of growth (12th day) and after the maturation of the cells (24th day), an analysis of the produced biomass was conducted, in terms of its biochemical components. The local isolate grew better than 211-11b, resulting in 1.43 mg L biomass compared to 1.02 mg L under 25 mg NH-N L, while organic carbon and nutrient consumption varied between the two strains and different conditions. Concerning biomass quality, a high initial NH-N concentration led to high protein content, while low nitrogen levels favored fatty acid (FA) accumulation, though the production of pigments was inhibited. In particular, the protein content of the final biomass was determined close to 45% of the dry weight in all experimental scenarios with adequate nitrogen, while proteins decreased, and the fatty acids approached 20% in the case of the local isolate grown on the substrate with the lowest initial ammonium nitrogen (25 mg NH-N L). The novelty of the present work lies in the comparison of a microalga with industrial applications against a local isolate of the same species, which may prove to be even more robust and profitable.
微藻最近被认为是有效处理厌氧消化废水的一种很有前途的替代方法。然而，迄今为止，由于高氨浓度和浊度等多种限制因素，仍然没有广泛应用的基于微藻的工艺，这两种因素都阻碍了微藻的生长。在这一范围内，本研究的目的是研究两种菌株，SAG 211-11b 和一种当地的阿尔及利亚分离株，在不同氮水平下，通过氨汽提的性能。实验在圆柱形光生物反应器中进行，控制 pH 值（7.8±0.2）和温度（25±2°C）。监测生物量生产和基质消耗情况。在生长的稳定阶段（第 12 天）开始和细胞成熟（第 24 天）后取样，对产生的生物质进行生化成分分析。与 25 mg NH-N L 相比，当地分离株的生长情况优于 211-11b，生物量达到 1.43mg L，而有机碳和营养物质的消耗在两种菌株和不同条件之间有所不同。就生物质质量而言，高初始 NH-N 浓度导致高蛋白含量，而低氮水平有利于脂肪酸（FA）的积累，尽管色素的生产受到抑制。特别是，在所有实验条件下，初始氮充足时，最终生物质的蛋白质含量接近干重的 45%，而在当地分离株以最低初始铵氮（25mg NH-N L）为底物生长时，蛋白质减少，脂肪酸接近 20%。本工作的新颖之处在于比较了一种具有工业应用前景的微藻与同一种微藻的当地分离株，后者可能更具弹性和更有利可图。
