Current advances and challenges in microbiome-based mitigation of volatile organic compounds from livestock waste...

Odor emissions from animal waste represent a persistent challenge in livestock production, with implications for animal welfare, environmental quality, and the societal sustainability of farming. These emissions are primarily driven by volatile organic compounds (VOCs) generated through microbial degradation of feces and urine, including ammonia, sulfur-containing compounds, volatile fatty acids, and aromatic metabolites. Conventional odor control strategies rely largely on physical, chemical, or management-based approaches, which often provide inconsistent or short-term mitigation and raise concerns regarding cost and sustainability. Advances in microbiome research have highlighted the central role of gut-associated and manure-associated microbial communities in shaping VOC production, positioning microbiome engineering as a promising novel biological alternative for odor mitigation. This review synthesizes current knowledge on microbiome-based strategies targeting VOCs in animal waste, including dietary modification, probiotic and functional microbial consortia approaches, as well as post-excretion bioaugmentation. This review evaluates also the microbial basis, health and biosecurity relevance, and practical limitations of these mitigation strategies. While microbiome engineering shows considerable potential, its effectiveness remains highly context dependent, and broader adoption is constrained by variability across production systems and limited farm-scale validation. Future interventions will require mechanism-driven research, standardized methodologies, and integration within comprehensive waste management frameworks to support sustainable livestock production.