Staged Microbial Consortium Valorizes Cattle Manure Wastewater and Promotes Maize Growth.

Area of Science:

• Microbiology
• Agricultural Science
• Biotechnology

Background:

• Ammonia-oxidizing bacteria are crucial for nitrogen cycling and agricultural waste utilization.
• Challenges in large-scale application include high costs and instability.
• Developing cost-effective and stable microbial solutions is essential for sustainable agriculture.

Purpose of the Study:

• To create a low-cost, stable microbial consortium for converting cattle manure wastewater.
• To investigate the mechanisms behind the consortium's bioactive fermentation broth production.
• To evaluate the consortium's impact on soil nitrogen transformation and plant growth.

Main Methods:

• Utilized Ensifer sp. S2-8-1 as the core strain and Bacillus subtilis as the auxiliary strain.
• Compared monoculture, simultaneous co-culture, and staged consortium (SYC) cultivation systems.
• Conducted soil-maize pot experiments and comparative metatranscriptomic analysis.

Main Results:

• The SYC system demonstrated superior performance with the highest viable bacterial density.
• SYC significantly enhanced rhizosphere nitrification, NO₃⁻-N availability, and maize growth (41.4% increase in dry matter).
• Metatranscriptomics revealed coordinated activation of ammonia oxidation and cytokinin pathways.

Conclusions:

• The staged consortium effectively converts cattle manure wastewater into a stable, bioactive fermentation broth.
• This strategy enhances microbial biomass and plant growth-promoting activity.
• Provides a scalable method for livestock wastewater valorization and compound microbial fertilizer development.