Microalgal-bacterial consortia can treat biogas slurry and produce high-value products. This study found that co-cultures of Desmodesmus sp. and Bacillus megaterium improved nutrient removal, biomass production, and lipid accumulation in Desmodesmus sp. Dual transcriptomic analyses revealed that B. megaterium upregulated genes associated with glycolysis, the Calvin cycle, tricarboxylic acid cycle, indole acetic acid synthesis, and fatty acid biosynthesis in Desmodesmus sp. Under a high C/N ratio, key genes involved in fatty acid degradation were downregulated, promoting lipid accumulation in co-cultured Desmodesmus sp. Effective NH4+-N removal in the co-culture under a high C/N ratio was attributed to microbial interactions. Desmodesmus sp. downregulated the URE gene in bacteria, inhibiting urea hydrolysis, while B. megaterium upregulated the URE and gdhA genes in microalgae, promoting urea utilization and NH4+-N assimilation. This study provides new insights into the transcriptional regulation in nutrient assimilation and lipid metabolism in microalgal-bacterial consortia.

中文翻译：

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微藻-细菌共培养的生理和转录组反应揭示了沼液处理过程中的营养去除和脂质产生


微藻细菌联盟可以处理沼液并生产高价值产品。本研究发现，Desmodesmus sp. 和 Bacillus megaterium 的共培养改善了 Desmodesmus sp. 的营养去除、生物量产生和脂质积累。双重转录组学分析显示，B. megaterium 上调了 Desmodesmus sp 中与糖酵解、卡尔文循环、三羧酸循环、吲哚乙酸合成和脂肪酸生物合成相关的基因。在高 C/N 比值下，参与脂肪酸降解的关键基因下调，促进共培养 Desmodesmus sp 中的脂质积累。在高 C/N 比值下，共培养物中 NH4+-N 的有效去除归因于微生物相互作用。Desmodesmus sp. 下调细菌中的 URE 基因，抑制尿素水解，而 B. megaterium 上调微藻中的 URE 和 gdhA 基因，促进尿素利用和 NH4+-N 同化。本研究为微藻-细菌联盟营养同化和脂质代谢中的转录调控提供了新的见解。