Protocol to select efficient microorganisms to treat coffee wastewater

Area of Science:

• Environmental Microbiology
• Wastewater Treatment Technologies
• Applied Microbiology

Background:

• Coffee processing wastewater (CPWW) presents environmental challenges due to high organic/inorganic loads and low pH.
• Indigenous microbial communities in CPWW are diverse and possess potential for bioremediation.
• Effective treatment strategies are crucial for sustainable CPWW management and reuse.

Purpose of the Study:

• To select a robust microbial consortium from CPWW for efficient biological treatment.
• To evaluate the consortium's effectiveness in reducing key pollutant parameters in CPWW.
• To assess the impact of the microbial treatment on CPWW eco-toxicity.

Main Methods:

• Phenotypic assays were used to select a bacterial consortium from indigenous CPWW microbiota.
• The selected consortium, comprising specific strains of Serratia, Corynebacterium, and Acetobacter, was used as inoculum.
• Physico-chemical parameters (BOD, COD, N, P, pH) and eco-toxicity (Daphnia similis) were measured before and after treatment.

Main Results:

• The selected bacterial consortium demonstrated high activity (11.18 log CFU mL⁻¹).
• Significant reductions were achieved: 85% in biochemical oxygen demand (BOD), 60% in chemical oxygen demand (COD), and 80% in phosphorus and nitrogen.
• Eco-toxicity was reduced by over 59%, and the final pH shifted to a neutral range (7.5).

Conclusions:

• The selected microbial consortium is highly effective for the biological treatment of CPWW.
• The treatment significantly improves water quality by reducing pollutants and eco-toxicity.
• The robustness of the selected strains ensures efficient CPWW treatment irrespective of wastewater physico-chemical variations.