Substrate-specific interactions of dual-consortia system of Bacillus megaterium and Pseudomonas putida for optimized nutrient recovery

Abstract Phosphorus (P) recovery from waste byproducts is essential for nutrient recovery, yet its bioavailability in inorganic and organic waste remains a challenge. This study investigates the phosphate solubilization potential of Bacillus megaterium and Pseudomonas putida , both individually and in a dual-consortia system, on sewage sludge ash (SSA), fish meal (FM), and their mixture. Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM) analyses were conducted to assess biochemical transformations and microstructural modifications post-solubilization. Kinetic modeling using the Hill equation demonstrated distinct solubilization patterns, where P. putida excelled in acid-mediated phosphate release from SSA, while B. megaterium exhibited strong enzymatic mineralization of organic phosphorus in FM. The consortium treatment displayed intermediate effects, balancing acid production and enzymatic degradation but without exceeding the highest-performing single strain. Principal Component Analysis (PCA) and statistical modeling confirmed that pH shifts, redox potential, and enzymatic activity were key drivers of microbial-mediated phosphate solubilization. The results suggest that targeted microbial inoculation based on waste type can optimize phosphorus recovery and improve the potential of nutrient recovery. Graphical Abstract