Development of a multi-strain bacterial consortium: Enhancing cow manure composting efficiency and maize growth

In this study, the effects of nine bacterial strains applied individually and as a multi-strain consortium on cow manure composting dynamics and subsequent maize growth were evaluated. The bacterial strains included Lactiplantibacillus plantarum, Lacticaseibacillus casei, Lentilactobacillus buchneri, Cereibacter sphaeroides, Streptomyces coelicolor, Acetobacter pasteurianus, (A) tropicalis, Bacillus licheniformis, and (B) subtilis. Microbial treatments significantly altered bio-compost physicochemical properties, with the consortium achieving maximum thermophilic temperatures of 65 °C during Days 5-21 and maintaining 34 °C at Day 60 compared to 28-33 °C for monocultures. The consortium treatment produced superior compost maturity indicators, including 16% higher total nitrogen content, 20% greater organic carbon retention, and a 18% higher C: N ratio relative to the control, reflecting enhanced nitrogen retention. Mineral nutrient availability was dramatically enhanced, with the consortium increasing phosphorus by 10% and potassium by 20% compared to the control. Greenhouse experiments demonstrated that bio-composts from microbial treatments significantly enhanced maize growth, with the consortium maximizing leaf length by 92%, stem length by 59%, and root length by 1.1-fold compared to controls. The consortium treatment increased fresh shoot biomass by 4.4-fold and dry shoot biomass by 1.9-fold relative to the negative control, while total chlorophyll and carotenoid concentrations increased by 1.1-fold and 2.2-fold, respectively. These improvements substantially exceeded both positive (uninoculated manure) and negative (soil-only) controls. Therefore, multi-strain microbial consortium synergistically enhanced compost quality through functional redundancy, nutrient availability, and plant productivity, offering a sustainable strategy for converting cow manure into high-value bio-fertilizer with possible potential for agricultural scale-up.