Microrganisms selection for production of mixedinoculum for depuration of wastewater from coffee processing

Abstract

Processing techniques with water use can improve the quality of coffee, but generate a large volume of wastewater containing high pollutant load. Due to the presence of pollutants, it is necessary to have an adequate treatment of these waters, before their disposal in the environment or recirculation. The use of biological treatment with microorganisms is a viable and efficient alternative for the improvement of effluent characteristics. Bioremediation of native microorganisms may be advantageous since the introduced microorganisms have the ability to degrade specific compounds, in addition to the adaptation of environmental conditions. In this sense, the objective of this work was to isolate and characterize the microbiota present in wastewater from coffee bean processing (WP), in order to select microorganisms capable to promote the reduction of the pollutant load of these effluents. Thus, the isolation and characterization of morphological, biochemical and protein profile of the microorganisms were made. It was observed a higher population density of bacteria occurring mainly in the presence of greater amount of dissolved oxygen (9.9 x 10 11 CFU mL -1 ). A mixed inoculum composed of Serratia marcescens CCMA 1010 and CCMA 1012, Corynebacterium flavescens CCMA 1006 Acetobacter indonesiensis CCMA 1002 was selected based on analysis of biological parameters of growth of the microorganisms, and chemical physicists of the WP treated in laboratory scale. The clearance of the pollutants was verified in the WP from the Brazilian Cerrado and Atlantic Forest regions. In addition, the biological treatment promoted by the selected mixed inoculum was evaluated in the ARC under field conditions in a prototype of the Wastewater Treatment Plant (WTP) at a coffee producing farm in the municipality of Patrocínio, Minas Gerais, Brazil. The inoculation of microorganisms showed removal of 85.46% in the BOD and 83.05% in the COD of the WP in the laboratory and 33% in the BOD and 25% in the COD in the pilot WTP under field conditions. Reduction in sugars and some acids as well as in toxicity were also observed both in the laboratory and in the pilot WTP.