Hydrogen excess drives metabolic reprogramming and viral dynamics in syngas-converting microbiomes

, coupled with upregulation of CRISPR-Cas and restriction-modification systems that correlate with diminished activity of an associated phage, indicating activated host defenses against viral threats. Concurrently, bacterial species such as those from Tepidanaerobacteraceae enhance carbon fixation via the Wood-Ljungdahl pathway, serving as electron sinks to mitigate redox imbalance. These adaptive responses highlight the microbiome's resilience mechanisms under stress, revealing viruses as both stressors and selective forces in syntrophic systems. Such insights advance our understanding of microbiome dynamics in bioconversion processes and guide the engineering of more stable microbial consortia for optimized syngas-to-methane conversion amid variable feedstocks.