Avaliação da eficiência de biorremediadores à base de microrganismos eficientes na redução de compostos nitrogenados e fosfatados em meio líquido

Abstract

Aquaculture is the fastest-growing food production activity worldwide, driven mainly by population growth, economic profits, and demand for alternatives to terrestrial livestock production. There is great expectation that Brazil will become one of the world's leading producers of aquatic foods, and the environmental and procedural challenges of the activity must be overcome to achieve this national aquaculture potential. Mitigation and control strategies for undesirable compounds, such as bioremediation with microorganisms, are gaining attention in aquaculture management and improving the technical and financial viability. However, the use of these microorganisms has significant limitations that need to be considered, particularly regarding the definition of the most efficient microbial consortia and protocols for their use. The research proposed here aimed to evaluate the action of multispecific microbial bioremediators (fermented Endogenic Efficient Microorganisms – EEM, prospectively obtained from the riparian forest, Non-Sulfur Purple Bacteria - BPNS, and a commercial formulation - Stability®) which were applied in artificially eutrophicated liquid media. Physicochemical parameters (temperature, OD, pH, and electrical conductivity) and chemical parameters (alkalinity, hardness, ammonia, nitrite, nitrate, total phosphorus, phosphate, phosphorus pentoxide, and carbon dioxide) were determined before and after the addition of bioremediators at 6, 12, and 24 hours post-treatment. The results indicated that the treatment with BPNS was the most effective in reducing ammonia (90% - 24h), and phosphate (64% - 24h). The treatment with EEM also reduced levels of phosphate (41% - 24h), however, despite the observed ammonia consumption up to 12 hours of testing (60%), there was a significant increase in ammonia concentration at 24 hours (188%). Considering the dynamics observed in water quality parameters, especially those related to the buffer system (alkalinity, hardness, and pH), in addition to the reduction of ammonia and phosphorus, the simultaneous application of these bioremediators (EEM and BPNS) may promote synergistic effects, therefore recommending the evaluation of the combined effect of these microbial consortia in future studies. Furthermore, identifying microbial groups is essential for risk assessment when considering aquaculture applications.