Physiological and transcriptomic responses of microalgal-bacterial co-culture reveal nutrient removal and lipid production during biogas slurry treatment

Dan Li; Ruiqing Liu; Ying Chu; Qiang Wang; Meilin He; Changhai Wang

doi:10.1016/j.biortech.2024.131810

Physiological and transcriptomic responses of microalgal-bacterial co-culture reveal nutrient removal and lipid production during biogas slurry treatment

Bioresour Technol. 2024 Nov 12:131810. doi: 10.1016/j.biortech.2024.131810. Online ahead of print.

Authors

Dan Li¹, Ruiqing Liu², Ying Chu², Qiang Wang³, Meilin He⁴, Changhai Wang⁵

Affiliations

¹ School of Civil Engineering, Yantai University, Yantai 264005, China.
² College of Resources and Environmental Science, Nanjing Agricultural University, Nanjing 210095, China.
³ State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng 475004, China.
⁴ College of Resources and Environmental Science, Nanjing Agricultural University, Nanjing 210095, China; Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Nanjing 210095, China; Jiangsu Provincial Key Laboratory of Coastal Saline Soil Resources Utilization and Ecological Conservation, Nanjing Agricultural University, Nanjing 210095, China. Electronic address: [email protected].
⁵ College of Resources and Environmental Science, Nanjing Agricultural University, Nanjing 210095, China; Co-Innovation Center for Jiangsu Marine Bio-Industry Technology, Lianyungang 222005, China. Electronic address: [email protected].

PMID: 39542053
DOI: 10.1016/j.biortech.2024.131810

Abstract

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.

Keywords: Lipid accumulation; Microbial interactions; NH(4)(+)-N metabolism; Transcriptomic profiling; Wastewater treatment.