Development of a synergistic tripartite consortium and hybrid growth media for enhanced methane oxidation and assessment of in vitro plant growth-promoting traits.

The development of multifunctional microbial consortia for sustainable agriculture is often hindered by the incompatibility of cultivating autotrophic cyanobacteria and heterotrophic bacteria. To address this challenge, we developed an innovative hybrid growth medium that supports a three-part consortium comprising Anabaena doliolum BF4, Pseudomonas sp. MNR81, and Methylobacterium oryzae MNL7. This study evaluated the functional synergy of this consortium within an optimized hybrid environment and examined its subsequent impact on methane dynamics in soil microcosms. The tripartite consortium demonstrated superior nitrogen-fixing ability, exhibiting significantly higher acetylene reduction activity (~ 2500 nmoles C2H4 mg protein− 1 h− 1) than individual strains. It also produced the maximum Indole-3-Acetic Acid in both the presence and absence of tryptophan (158.56 ± 2.59 and 81.95 ± 0.55 µg ml− 1), suggesting robust biochemical potential for root development. Furthermore, the consortium showed a significant reduction in methane flux in the soil microcosms. Compared with uninoculated soil (T1), which had high cumulative methane emissions (~ 2750 µg CH4 kg soil− 1 day− 1), the consortium (T8) acted as an effective methane sink, reducing cumulative emissions by more than 50% (~ 1250 µg CH4 kg soil− 1 day− 1). Temporal analysis confirmed that the consortium effectively reduced methane flux on day 20. These results suggest that co-inoculation of these microbial groups creates a synergy, functioning as a methane sink while providing essential nutrients. This approach offers a promising, environmentally friendly strategy for low-emission agriculture.