State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
Sci Total Environ. 2024 Apr 20;922:171339. doi: 10.1016/j.scitotenv.2024.171339. Epub 2024 Feb 28.
Inappropriate sterilization strategies inhibit microalgal growth when culturing microalgae with anaerobic digestate. This study aimed to scientifically select a low-cost disinfection pretreatment of anaerobic digestate for large-scale microalgae cultivations. In this work, three different methods, including autoclaving, ultraviolet or NaClO treatments, were employed to sterilize the municipal anaerobic digestate. Scenedesmus quadricauda was then cultured in diluted liquid digestate for the simultaneous lipid production and nutrient removal. The results indicated that the growth of S. quadricauda was inhibited after NaClO treatment due to the residual free chlorine. The 15-min ultraviolet effectively mitigated microbial contamination and increasing nutrient availability, enhancing the electron transport of microalgal photosynthesis. After 6-days cultivation, the microalgal biomass concentration of the ultraviolet group was 1.09 g/L, comparable to that of the autoclaving group (1.15 g/L). High nutrient removal efficiency was observed: COD (93.30 %), NH-N (92.56 %), TN (85.82 %) and TP (95.12 %). Moreover, S. quadricauda outcompeted the indigenous microorganisms, contributing to its dominance in the culture system of ultraviolet group. The facultative anaerobe Comamonadaceae and aerobes Moraxellaceae, rather than strict anaerobe Paludibacteraceae and Bacteroidetes_vadinHA17, played vital roles in synergistic removal of contaminants by bacteria and algae. The potential competition for nitrogen and phosphorus by bacteria contributed to the ultraviolet group having the greatest lipid content (48.19 %). Therefore, this work suggested using 15-min ultraviolet treatment for anaerobic digestate in large-scale microalgae cultivation.
在利用厌氧消化物培养微藻时，不当的灭菌策略会抑制微藻的生长。本研究旨在科学选择一种低成本的厌氧消化物消毒预处理方法，用于大规模的微藻培养。在这项工作中，采用了三种不同的方法，包括高压灭菌、紫外线或 NaClO 处理，对市政厌氧消化物进行灭菌。然后将四角藻在稀释的液体消化物中培养，以实现同时生产脂质和去除营养物质。结果表明，由于残留的游离氯，NaClO 处理后四角藻的生长受到抑制。15 分钟的紫外线有效地减轻了微生物污染，增加了营养物质的可用性，增强了微藻光合作用的电子传递。经过 6 天的培养，紫外线组的微藻生物量浓度为 1.09g/L，与高压灭菌组（1.15g/L）相当。观察到高的营养物质去除效率：COD（93.30%）、NH-N（92.56%）、TN（85.82%）和 TP（95.12%）。此外，四角藻抑制了土著微生物，使其在紫外线组的培养系统中占据优势。兼性厌氧菌 Comamonadaceae 和需氧菌 Moraxellaceae 而不是严格厌氧菌 Paludibacteraceae 和 Bacteroidetes_vadinHA17 在细菌和藻类协同去除污染物方面发挥了重要作用。细菌对氮和磷的潜在竞争导致紫外线组具有最大的脂质含量（48.19%）。因此，本工作建议在大规模微藻培养中使用 15 分钟的紫外线处理厌氧消化物。
