Biofertilization using microalgae-bacteria consortium for phenolic stress mitigation of sprouted barley: Functional genes profiling of soil bacteria

As alternatives to conventional chemical fertilizers, biofertilizers have gained attention, in particular, microalgae-bacteria co-culture biofertilizers (MBCFs) are promising candidates owing to their synergistic interactions. Excessive sludge has been considered a sustainable source of MBCFs due to its proper nutrient composition and biodiversity. This study investigated the feasibility of MBCFs in promoting plant growth. The sprouted barley, selected as a model plant, was exposed to the phenolic stress, and its alleviatory effect by MBCFs was evaluated. The plant's growth characteristics such as germination rate, weight, and length were enhanced after adding MBCFs even under phenol exposure. Desmodesmus and Polaromonas were predominant microalgae and bacteria genus, respectively, and those are attributed to possess the phenol-degrading and plant-promoting properties. The bacterial functional gene prediction revealed several putative genes, including gst (Glutathione R-transferase) and exbB (Iron complex outermembrane recepter protein), which act to promote plant growth. This study suggests that the protective and promotive functions of MBCFs enhance the growth of sprouted barley and alleviate phenolic stress.