title: A review on hydrolytic enzymes in the treatment of wastewater with high oil and grease content.
abstract: Wastewater from dairies and slaughterhouses contains high levels of fats and proteins that present low biodegradability. A large number of pretreatment systems are employed to remove oil and grease (O&G) to prevent a host of problems that may otherwise arise in the biological process, and reduce the efficiency of the treatment station. Problems caused by excessive O&G include a reduction in the cell-aqueous phase transfer rates, a sedimentation hindrance due to the development of filamentous microorganisms, development and flotation of sludge with poor activity, clogging and the emergence of unpleasant odors. Therefore the application of a pretreatment to hydrolyze and dissolve lipids may improve the biological degradation of fatty wastewaters, accelerating the process and improving time efficiency. However thus far, only a few studies describing the degradation of fats and oils by alkaline/acid/enzymatic hydrolysis have been reported; the treatment of effluents from several origins is a new and promising application for lipases. Among the strains that produce the hydrolytic enzymes studied, the fungus Penicillium restrictum is a particularly promising one. When cultivated in low-cost solid medium composed of agro-industrial waste, P. restrictum produces a pool of hydrolases capable of degrading the most complex organic compounds. This degradation enables a considerable increase in organic matter removal efficiency to be realized, which results in the attainment of a high-quality effluent in the subsequent biological treatment stage. Consequently, there is presently a wide variety of ongoing scientific investigation in the field of developing enzymatic hydrolysis processes to precede traditional biological treatment.
authors.affiliation: School of Chemistry, Federal University of Rio de Janeiro, Rio de Janeiro, RJ 21945-970, Brazil. christe@eq.ufrj.br
authors.forename: M C
authors.initials: MC
authors.lastname: Cammarota
authors.forename: D M G
authors.initials: DM
authors.lastname: Freire
mesh_terms: D001673:Biodegradation, Environmental; D005223:Fats / Q000378:metabolism*; D005285:Fermentation; D019649:Food Industry; D006867:Hydrolases / Q000378:metabolism; D006868:Hydrolysis; D009821:Oils / Q000378:metabolism*; D010407:Penicillium / Q000201:enzymology; D014865:Waste Disposal, Fluid; D018508:Water Purification / Q000592:standards
chemical_list: D005223:Fats; D009821:Oils; D006867:Hydrolases