Purpuse: Fodder yeast is obtained in an aerobic fermentation process where foaming is a major problem to be solved. In this article, the antifoam property of crude and puri ed lter cake oil is evaluated in order to use this residual as an alternative to replace the import of commercial antifoam agents and to reduce the production costs of fodder yeast Method: Knock down test and the comparisons with two commercial antifoam agents were done.Blackstrap molasses medium at 20 and 40 g/L of total reducing sugar was used. All products were studied in their pure form and commercial ones also in dilutions 1:2 and 1:5 v/v. Hansen's solubility parameters (HSPs) to analyze the a nity of each defoamer for yeast were determined.Results: It was obtained the crude and puri ed lter cake oil showed similar behavior to commercial defoamers with an immediate antifoam effect, removing between 40 and 60% of the initial foam at both sugar concentrations in the rst 5 minutes. The regression model showed puri ed lter cake oil has the greatest knockdown effect (Ca = 55.85 and 74.32) and with greater foam suppression stability the commercial defoamer Quimifoam Máster (C b = -0.69 and -1.38). Ra values obtained in HSPs test, indicated the a nity of defoamers to the medium. Conclusion:Puri ed lter cake oil is an effective product for its use as an antifoam with the best knock down effect for both concentrations of sugars in the medium. The determination of HSPs corroborates the effectiveness of this product to suppress foam. Statement Of NoveltyThe use of crude lter cake oil, residual from the Cuban sugarcane derivatives industry, as an antifoam was previously studied in the 90s using it as a fatty vehicle in mixtures with esters, achieving good results. In the bibliography consulted by the authors, no recent articles are reported on its use after it has been puri ed. Therefore, the novelty of this work is the evaluation of the antifoam property of puri ed lter cake oil, which offers the possibility of a new use of this by-product with the consequent impact on the reduction of fodder yeast production cost by the replacement of commercial defoamers, products that are imported and with high prices in the market.

Purpuse: Fodder yeast is obtained in an aerobic fermentation process where foaming is a major problem to be solved. In this article, the antifoam property of crude and purified filter cake oil is evaluated in order to use this residual as an alternative to replace the import of commercial antifoam agents and to reduce the production costs of fodder yeastMethod: Knock down test and the comparisons with two commercial antifoam agents were done. Blackstrap molasses medium at 20 and 40 g/L of total reducing sugar was used. All products were studied in their pure form and commercial ones also in dilutions 1:2 and 1:5 v/v. Hansen's solubility parameters (HSPs) to analyze the affinity of each defoamer for yeast were determined.Results: It was obtained the crude and purified filter cake oil showed similar behavior to commercial defoamers with an immediate antifoam effect, removing between 40 and 60% of the initial foam at both sugar concentrations in the first 5 minutes. The regression model showed purified filter cake oil has the greatest knockdown effect (Ca = 55.85 and 74.32) and with greater foam suppression stability the commercial defoamer Quimifoam Máster (Cb = -0.69 and -1.38). Ra values obtained in HSPs test, indicated the affinity of defoamers to the medium. Conclusion: Purified filter cake oil is an effective product for its use as an antifoam with the best knock down effect for both concentrations of sugars in the medium. The determination of HSPs corroborates the effectiveness of this product to suppress foam.

Purpose Vinasse is one of the organic industrial effluents with major polluting effect. The objective of this work was to perform a techno-economic assessment of vinasses treatment alternatives for valorization of this waste through process simulation with Aspen Hysys v10.0. Methods Four alternatives were studied: (A_1) incineration and electricity generation, (A_2) desalinization, (A_3) anaerobic digestion and electricity generation and (A_4) drying. The selected packages for the evaluation and prediction of properties were: Lee-Kesler-Plöcker and NBS Steam, NRTL-Ideal, Peng-Robinson-Stryjer-Vera and NBS Steam and NRTL-Ideal respectively; the validation in these cases was carried out with data reported in the literature. The economic evaluation was carried according to the changes that each alternative determines in each one of the elements of effective cash flow comparing with the actual condition. Results With the alternative A_1, fertilizers ashes are obtained removing all the residual and the energy generation. By the alternative A_2, fertilizers salts and desalinate vinasses (for animal food) were obtained. By the alternative A_3, energy is generated from biogas. By the alternative A_4, dry vinasse is obtained which is used as fertilizer and animal food. Conclusion The polluting effect of the vinasse can be reduced with the proposed treatment alternatives. It was showed that the alternatives are feasible, being the alternative A_1 the best, with a NPV of $ 1.29 MMUSD, IRR 25.5% and DPBP 2.7 years. Process simulation are a valuable supporting tool when making decisions in investment projects for valorization of vinasse from the ethanol industry.