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The development of fast analytical techniques is essential for the monitoring and control of the sugar manufacturing process and in ethanol production. In this work, the techniques to determine ethanol concentrations were analyzed and it was specified in those used in the wine, beer and rum industry. The most widely used techniques are chromatography, spectrophotometry and redox titration. Chromatography and spectrophotometry have the advantages of the precision of the results but require equipment that can be expensive. Redox titration was the analytical technique selected because it is accurate, feasible, and economical. This technique not require expensive equipment, electricity or gas. For the determination of the ethanol concentration in a sample obtained by fermentation, the redox titration technique has few interferences with the other components of the medium, since unlike chromatography, it can be used when there are impurities. The experimental setup was set up and the method calibration curve was made. Preliminary results indicated that the calibration curve is linear, so it can be used to determine the ethanol concentration in a sample obtained by fermentation. [ABSTRACT FROM AUTHOR]

Candida utilis (torula yeast) is the most widely used yeast as an animal feed supplement due to its high content of B vitamin, minerals and amino acids, therefore, in order to use it as food, studies have been carried out to increase its growth rate and production, highlighting the use of magnetic fields. This paper constitutes a review of the main characteristics of this yeast, its use as an alternative food worldwide and in Cuba, as well as the effect of the application of magnetic fields on its growth. The results of the review carried out show that Candida utilis is used in the production of unicellular protein, due to its ability to use a variety of carbon sources, being able to replace traditional protein sources. Although several investigations are reported in which the application of a static magnetic field causes an increase in the growth of fungi and yeasts, few reports were found in relation to the torula yeast, even so, it is found that low-intensity magnetic fields increase the cell biomass of this yeast. [ABSTRACT FROM AUTHOR]

Trichoderma sp. is used in the ecologic protection of tomato, pepper, cucumber and other crops. An alternative for increasing the efficiency of biological systems is the use of magnetic treatment of cell cultures. In this work, the microbial kinetics under growth stimulation conditions by the action of the magnetic field on Trichoderma harzianum Rifai (A-34) in solidstate fermentation is reportead. Microbial growth is described by a primary model. Two of the most applied and least complex models were compared using the OriginPro (OriginLab Inc.) version 9.4 (2017). For the statistical validation of the models, the residual values were studied applying the Akaike Information Criterion (AIC), adjusted R2, X² (Chi-square), Minimum square of residues and Test of Fischer. The normality of the residues was checked using the Kolmogorov-Smirnov test. Coefficients describing Gompertz and Logistic models were obtained for the control experiment and the one with the fungus treated with magnetic fields in aerated solid fermentation at 30 °C. Logistic model adjusted the experimental data more adequately, so it is selected to describe biomass formation. [ABSTRACT FROM AUTHOR]