Microbial profiling of swine-waste digestates: implications for biofertilizer application

Area of Science:

• Agricultural Science
• Environmental Science
• Microbiology

Background:

• Petroleum-based products cause significant pollution, driving the need for sustainable energy and agricultural solutions.
• Digestate, a byproduct of biomethane production from organic waste, shows promise as a biofertilizer.
• Biofertilizers enhance soil health and support nitrogen-fixing bacteria, crucial for sustainable agriculture.

Purpose of the Study:

• To assess the biofertilizer potential of digestates derived from swine carcasses and effluent.
• To compare the physicochemical properties and microbial diversity of digestates from pilot-scale and laboratory-scale anaerobic digesters.
• To identify beneficial microbial communities within the digestates that can support plant growth.

Main Methods:

• Physicochemical analyses of digestates.
• Microbial diversity profiling using sequencing.
• Comparison of microbial communities between laboratory and pilot-scale digesters.
• Identification of key microbial genera and their relative abundance.

Main Results:

• Digestate from the laboratory-scale digester exhibited higher microbial diversity (Shannon index 7.6) than the pilot-scale digestate (Shannon index 5.4).
• Laboratory-scale digestate showed a greater abundance of beneficial genera such as Bacillus and Paenibacillus, known for plant growth promotion.
• Both digestates contained beneficial genera like Bacillus, Pseudomonas, and Bradyrhizobium, indicating potential for plant growth promotion, phosphorus solubilization, and nitrogen fixation.

Conclusions:

• Digestate from swine waste, particularly from laboratory-scale digestion with carcasses, possesses significant biofertilizer potential due to enhanced microbial diversity.
• The presence of specific beneficial microbes like Bacillus and Paenibacillus in laboratory-scale digestate suggests superior plant growth-promoting capabilities.
• Further research, including metabolic pathway analysis and field trials, is necessary to fully understand the implications of swine waste digestate microbiota for agricultural applications.