Produção e aplicação de lipase fúngica na degradação do efluente de uma indústria de sorvetes

Abstract

Different types of industries generates effluents in their processes. Depending on the activity, the characteristics of the wastewater produced vary considerably. The ice cream industry has high organic load wastewater from milk, which is its main raw material, reflecting in a residue with high Chemical Oxygen Demand (COD) and high content of oils and greases. However, the accumulation of fats in the system affects the efficiency of treatment of the generated effluent. In a way to eliminate such difficulties, the use of biocatalysts as enzymes is studied, especially lipases, which act in the hydrolysis of oils and fats, thus reducing the amount of lipids in the effluents. Thus, the present study aimed to produce and apply a fungal lipase for effluent degradation of an ice cream industry. Lipase of the endophytic fungus Talaromyces sp., Isolated from an Amazonian host, was produced in submerged cultivation and used for effluent degradation. The enzyme was produced in Erlenmeyers with 100 mL medium containing 1% olive oil and pH 6. The maximum lipolytic activity obtained was 3.192 ± 0.029 U / mL after 144 h of cultivation. This enzymatic extract was applied directly to the autoclaved effluent and the raw effluent (without autoclaving). The effectiveness of fat hydrolysis was evaluated based on the acidity index (A.I) and COD. There was a decrease in COD and an increase in A.I after 4 h. Enzymatic treatment with raw effluent was studied using a complete factorial design with two variables (pH and enzymatic concentration) and two levels (pH = 3.5 and 7.0; enzymatic concentration = 12.8 and 25.50 U/ml) for 4 h. The experiments were performed by evaluating COD removal and increase in A.I. Through Pareto graphs (p <0.05) was verified the statistic influence of pH on the A.I. Using pH 7.0 and 12.8 U/mL lipase, it was possible to obtain the best effluent degradation results (88.46% COD removal and 22.22 % increase in A.I.). The oil and fat content (TOG) was determined both in the raw effluent and in those experiments performed at pH 7.0, in both enzymatic concentrations. The TOG reduction was 88.72 % (with 12.8 U / mL) and 94.50 % (with 25.5 U/mL). The results of this work, besides showing the variables that interfere with the effluent degradation of the ice cream industry, justify the studies of high lipid effluent treatment through the application of fungal lipase.