Bacterial multi-enzyme signature assessment for wastewater reclamation and ecological resilience in tropical waste stabilization pond

Wastewater nutrient dynamics is characterized by the enhanced activities of microbial enzyme complex resulting in the decomposition of domestic sewage and maintaining ecological resilience of a waste stabilization pond. This altered stress-induced bacterial metabolism has been studied for nutrient reclamation through bacterial multi-enzyme signature assessment (MESA) of domestic wastewater. Strong correlation between the protease activity (PA) and NH4-N (r = 0.918) and proteolytic bacteria (r = 0.990) at the inlet suggests a consistent protein degrading activity (2 U/ml) of high-protein load present in inflowing organic nitrogenous waste products indicating the predominance of ongoing ammonification process. Higher correlation between PO4-P and alkaline phosphatase activity (APA) at the inlet (r = 0.866) and outlet (r = 0.968) than the mid-site (r = 0.654) suggests substrate dependent but enzyme limited high phosphate uptake at inlet by biological integrity and PO4-P reclaimed favorable environment (PO4-P: 1 +/- 0.02 mg/l) for bacterial growth at outlet. Higher cellulase activity (CA) being positively correlated with organic-C (r = 0.839) at the oxygen-deficient inlet site revealed efficient utilization of high organic-C load by both aerobic and facultative anaerobic cellulolytic bacteria and negative correlation between CA and BOD is due to aerobic organic matter degradation favored by grazing food chain dominated ecological integrity of mid-site and outlet. Enzyme signature index trend of APA > PA > CA clearly revealed higher nutrient and BOD-COD removal than carbon metabolism by the present system dynamics being influenced by a shifting dominance of substrate-induced to enzyme-induced bacterial metabolism from sewage inflow to outflow. Thus, MESA reveals the adaptation of wastewater grown nutrient cycling bacteria to luxuriant storage of nutrients in excess of their requirement mediated by their released enzymes responsible for wastewater reclamation and ecological resilience.