Journal article

Publication year: 2025

Journal: Total Environment Microbiology

Volume number: 1

Issue number: 4

Open access status: Gold

DOI Link: https://doi.org/10.1016/j.temicr.2025.100033

Publisher: Elsevier

Abstract: 

High-rate algae ponds (HRAPs) efficiently remove nitrogen and phosphorus from wastewater and the produced microalgal biomass can be used as NPK-rich fertilizer in a sanitation‒agricultural circular economy. The effects of microalgal based organic fertilizer on plant growth are well documented, but the knowledge of effects on the plant microbiome is scarce. We analysed the rhizosphere and root microbiome of wheat seven weeks after fertilization with microalgal biomass harvested from a HRAP used for municipal wastewater treatment. Plants fertilized with a NPK mineral fertilizer, unfertilized control plants, and the microalgal biomass were studied in parallel. Three fertilizer levels, 60, 120, and 180 kg N ha^-1, were compared. The bacterial community associated with microalgal biomass was dominated by few taxa including potential plant growth-promoting bacteria (PGPBs) and potentially pathogenic bacteria. Root-associated bacterial communities were more sensitive to fertilization than those of the rhizosphere. Fertilization with microalgal biomass increased the bacterial abundance in roots, but the diversity and composition of the root microbiome hardly changed. Only few taxa increased significantly in relative abundance after fertilization with microalgal biomass, while the mineral fertilizer reduced the bacterial abundance and diversity in roots. Escherichia coli, 3rd generation cephalosporine resistant (3GCR) E. coli, and enterococci were cultivated only from microalgal biomass and plants fertilized with it, while potentially pathogenic bacteria tolerant to biocidal compounds and antibiotic resistance genes (ARGs) were detected in all samples. Although the microalgae-based organic fertilizer derived from a wastewater treating HRAP provides a sustainable source of nutrients, its contribution to the spread of antibiotics, biocidal compounds, and antimicrobial resistance in agricultural systems should be further evaluated.

Harvard Citation style: Ollo, E., Mückschel, F., Velten, H., Heyde, B., Siemens, J., Kämpfer, P., et al. (2025) Fertilization with microalgal biomass of wastewater treatment high-rate algae ponds (HRAP): Effects on the wheat root microbiome, Total Environment Microbiology, 1(4), Article 100033. https://doi.org/10.1016/j.temicr.2025.100033

APA Citation style: Ollo, E., Mückschel, F., Velten, H., Heyde, B., Siemens, J., Kämpfer, P., Theilen, U., Düring, R., Frei, M., & Glaeser, S. (2025). Fertilization with microalgal biomass of wastewater treatment high-rate algae ponds (HRAP): Effects on the wheat root microbiome. Total Environment Microbiology. 1(4), Article 100033. https://doi.org/10.1016/j.temicr.2025.100033