Biorremediação do soro do leite utilizando consórcio microalga-fungo

Abstract

The dairy industry is one of the main segments of the food sector due to its expressive and continuous growth. However, its production process generates a by-product known as whey that has a high polluting potential, and therefore its disposal is considered a huge problem for it. As regards, the physicochemical treatments commonly applied to this type of effluent are highly expensive, which makes their use unfeasible, especially for small and medium-sized industries. Bioremediation comes as a possibility to overcome this obstacle and to promote efficiently and with a lower associated cost the total or partial removal of pollutants found in whey. In this sense, this work aims to evaluate the use of fine fungi (Penicillium oxalicum Currie and Cunninghamella echinulata) and microalgae (Tetradesmus sp.) in the treatment of this whey effluent as well as to prove the advantages of using the fungi-microalgae consortium. Therefore, the remediation process was studied using 4 concentrations of whey (0.5%, 1%, 2%, and 4%) and 3 inoculum systems (fungus, microalgae, and the consortium) under constant agitation and lighting conditions. Whey was initially characterized by high levels of chemical demand for oxygen (52.886 mg O2.L-1), total nitrogen (1.563 mg.L-1), and total phosphorus (663.5 mg. L-1 in terms of phosphate). The results obtained in step 1 showed a superiority of the consortium in relation to systems with separate species (monosystems), especially when the effluent was used in a higher concentration. With the confirmation of the initial hypothesis, the whey treatment was carried out using a bubble column reactor and the consortium formed by the microalgae and the fungus Cunninghamella echinulata, which showed greater efficiency, and for this system two light intensities were evaluated (100 μmol.m-2.s-1 and 50 μmol.m-2.s-1), in addition to comparing the remediation potential of these microorganisms in relation to the natural contaminants of this medium (endogenous microorganisms) (control). Both systems that used the consortium showed lower residual values for the evaluated pollutants than the control. However, the light intensity of 100 μmol.m-2.s-1 stood out, allowing the treatment promoted by symbiosis to reach removal percentages of 91.3% for COD, 90.46% for FT and 77% for NT. As a result, the microalgae-fungus consortium presents itself as a potential alternative to promote the remediation of whey and also increase the production of biomass.