Enzymes in Treating Dairy Wastewaters
Technologies involving the use of milk whey and others dairy wastes for producing biogas are in continuous evolution. An important issue in anaerobic bioreactors is formation of viscous materials and suspensions. Oil and grease are part of this material, which has detrimental effect on process performance (i.e., clogging of the anaerobic reactors). The utilization of enzymatic treatments is a powerful tool to solve the problem, since it promotes hydrolysis of fats and sludge solids. Lipases are the most important enzymes applied to this aim, but proteases, amylases and cellulases also contribute to increased efficiency of the process (Leal et al., 2002; Roman et al., 2006). A major concern is the high cost of enzymes; the availability of low-cost formulations is fundamental for the economical sustainability of the plants. The employment of microbial enzymatic preparations obtained by solid-state fermentation is a good solution. They are a mix of enzymes with high lipolyitic activity and are mainly obtained from fungi such as Penicillium spp. (Cammarota and Freire, 2006).