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Cuban Journal of Agricultural Science

versión impresa ISSN 0864-0408versión On-line ISSN 2079-3480

Cuban J. Agric. Sci. vol.54 no.3 Mayabeque sept.-dic. 2020  Epub 01-Sep-2020


Animal Science

Chemical and microbiological characterization of Saccharomyces cerevisiae creams, obtained from different Cuban distilleries

Marlen Rodríguez1  *

Grethel Milián1

Ana J. Rondón1

R. Bocourt †2 

Lucía Sarduy2 

A. Beruvides1

1Centro de Estudios Biotecnológicos, Universidad de Matanzas, Autopista a Varadero, km 3 ½, Matanzas, Cuba

2Instituto de Ciencia Animal, Apartado Postal 24, San José de las Lajas, Mayabeque, Cuba


PROBIOLEV® symbiotic additive includes yeast cream from distillery in its formulation. It is characterized by improving the productive performance and health of animals of zootechnical interest. The objective of this study was to characterize the chemical and microbiological composition of five creams of Saccharomyces cerevisiae, obtained from different Cuban distilleries with the purpose of elaborating PROBIOLEV®. For the chemical characterization of creams, descriptive statistics was carried out on dry matter, ashes, crude and true protein, as well as reducing sugars, total carbohydrates and pH. From the microbiological point of view, a count of contaminating microorganisms was performed and organoleptic characteristics were analyzed.The bromatological evaluation showed values ​​between 15-20% of dry matter, 16-18% of ash, 80-85% of organic matter, 35-40% of crude protein, 32-36% of true protein, 4-6% of total carbohydrates and 2-4% reducing sugars. Creams were found not to contain contaminating microorganisms such as coliforms, Pseudomonas aeruginosa, Staphylococcus aureus, Salmonella and Bacillus cereus. From these results, it is concluded that the different creams of S. cerevisiae, without considering their distillery of origin, have adequate chemical and microbiological characteristics for their use in the production of PROBIOLEV®.

Keywords: Cuban distilleries; Saccharomyces cerevisiae; symbiotic additive

Saccharomyces cerevisiae creams are made from residues generated by industry, by distilling the product of alcoholic fermentation. They are a highly harmful for the environment. These creams are mainly composed by enzymes, peptides, amino acids, organic acids and B vitamins. Hence, their use in the formation of symbiotic biopreparations, in addition to having highly useful natural additives, prevents ecological damage and guarantees balance between industrial processes and their environment (Pérez et al. 2016 and Rodríguez 2017).

S. cerevisiae yeast is closely associated to progress and well-being of humanity. It is one of the most used and is widely marketed for its high biological value. It is placed among the most used fungal cultures for animal feeding as a stabilizer of the intestinal microbiota, and is intended for young and adult animals as adults (Carro et al. 2014 and Neeraj 2016). Health benefits and productivity of individuals consuming this yeast are documented (Rodríguez et al. 2015 and Hahn-Didde and Purdum 2016).

In Cuba, this residue from agro-industry is reused as a protein source to prepare diets that constitute an alternative to the use of conventional concentrates (Lezcano et al. 2010 and Solano et al. 2012). However, its treatment as raw material to make additives is a biotechnology option in Cuba, which is of interest for animal production. As reported, productive benefits of its use could be efficient (Machín et al. 2016, Pérez et al. 2016 and Rodríguez 2017).

Pérez (2000) characterized ten batches of cream from the José A. Echeverría distillery in Cárdenas, Matanzas. This study demonstrated the bromatological and microbiological stability of this product. However, it is not known whether there are differences with respect to creams from other distilleries, which may interfere with the quality of the symbiotic additive. Therefore, the objective of the current research was to characterize the chemical and microbiological composition of S. cerevisiae creams from different Cuban distilleries, in order to use them as main raw material in the production of PROBIOLEV®.

Materials and Methods

Origin of S. cerevisiae creams. Five yeast creams were used, coming from different enterprises producing alcohol and derivatives (figure 1). These plants use a lyophilized strain of S. cerevisiae, imported by the Instituto Cubano de Investigación de los Derivados de la Caña de Azúcar (ICIDCA).

Single samples (15 L) were taken out of an industrial batch of cream from each distillery. The procedure was homogeneous, stirring the cream in the fermentation vat for five minutes. Creams were poured into plastic tanks with lids and transferred to the microbiology laboratory of the University of Matanzas (UM), where they were stored (4 and 8 ºC) and processed by triplicate.

pH determination. A digital pH meter (Sartorius Meter PP-25) was used for measuring pH of creams.

Figure 1 Origin and experimental sequence used to determine chemical and microbiological indicators of the different distillery creams 

Analytical techniques for chemical characterization. Content of dry matter (DM), ash, organic matter (OM) and crude protein was determined for each cream batch using Kjeldalh method, according to the methodology described by AOAC (1995). For true protein, Berstein method, cited by Meir (1986), was used. The determination of total reducing sugars was performed according to the 3.5-dinitrosalicylic colorimetric technique, in which glucose was used as standard sugar (Bernfeld 1955). For measuring total carbohydrates, phenol-sulfuric acid colorimetric method was applied (Dubois et al.1956).

Microbiological determination of S. cerevisiae creams. The count of polluting microorganisms was carried out in accordance with the current standards, described for studies of microbiological quality of food for NC-ISO human and animal intake, according to Bennett and Lancette (2007) (table 1). For this, serial dilutions of samples (NC ISO 6887-1: 2002) were carried out and the techniques for the determination of polluting microorganisms were applied.

Table 1 Microbiological testsfor determining polluting microorganisms 

Microbiological tests NC- ISOreferences
Recounting of total and fecal coliforms 4832: 2010
Recounting of Pseudomonas aeruginosa 4833-1: 2014
Recounting of Staphylococcus aureus 6888-1: 2003
Recounting of Bacillus cereus 4833-1: 2014
Counting of Salmonella in 25 mL 6579: 2008
Counting of enterobacteria 4832: 2010

Organoleptic analysis. To determine organoleptic characteristics of each cream under study, a systematic control of its odor, color and appearance was carried out.

Statistical analysis. Descriptive statistics was performed on chemical data, for which mean, standard deviation and coefficient of variation (%) were determined. INFOSTAT statistical package, version 2012, was used (Di Rienzo et al. 2012)

Results and Discussion

Table 2 shows the descriptive analysis of each cream under study. Chemical characterization showed that mean values of each indicator are in correspondence with that reported by a group of authors (Álvarez 1995, Esperanza and Constanza 2007, Arratia 2009, Solano et al. 2010 and Solano et al. 2012).

Table 2 Chemical composition of the different Saccharomyces cerevisiae creams 

Indicators Cuban distilleries
José A. Echeverría Jesús Rabí Héctor Molina Heriberto Duquesne Melanio Hernández
Dry matter, % Mean 16.78 17.29 18.12 17.40 15.71
SD 0.09 0.10 0.06 0.07 0.17
CV, % 0.54 0.60 0.30 0.40 1.08
Ash, % Mean 18.14 18.25 17.35 16.75 17.08
SD 0.04 0.04 0.03 0.03 0.04
CV, % 0.23 0.23 0.17 0.18 0.29
Organic matter, % Mean 81.86 81.75 82.65 83.25 82.92
SD 0.04 0.04 0.03 0.03 0.04
CV, % 0.05 0.05 0.04 0.04 0.05
Crude protein, % Mean 38.95 39.20 40.27 39.77 38.16
SD 0.04 0.03 0.05 0.05 0.05
CV, % 0.09 0.06 0.12 0.12 0.13
True protein, % Mean 36.92 37.18 36.52 35.87 32.52
SD 0.04 0.07 0.09 0.04 0.08
CV, % 0.11 0.19 0.25 0.12 0.25
Reducing sugars, % Mean 4.12 3.96 4.52 4.86 4.23
SD 0.03 0.02 0.02 0.01 0.04
CV, % 0.61 0.53 0.34 0.21 0.85
Total carbohydrates, % Mean 5.25 4.94 6.32 5.97 5.06
SD 0.02 0.02 0.04 0.01 0.04
CV, % 0.29 0.42 0.64 0.19 0.69
pH Mean 3.83 3.44 4.78 3.52 4.81
SD 0.02 0.02 0.01 0.006 0.01
CV, % 0.45 0.60 0.24 0.16 0.21

Results are the average of three determinations

SD:standard deviation

CV:coefficient of variation

Studies carried out by Álvarez (1995), Pérez (2000) and Solano et al. (2010) in the bromatological evaluation of different S. cerevisiae creams showed ranges between 15-20% of DM, 16-18% of ash, 80-85% of OM, 35-40% of crude protein, 32-36% of true protein, 4-6% of total carbohydrates and 2-4% of reducing sugars. Minimum and maximum values for each indicator analyzed in this study correspond to the previously described intervals.

Pérez (2000) showed that S. cerevisiae cream, obtained from fermentation process in the alcohol industry, shows stability in its percentage values. According to Guevara et al. (2014), the success of a good fermentation depends on the effectiveness of several factors: sugar concentration, pH, optimal temperature, contamination by other microorganisms, use of an organism resistant to high concentrations of alcohol, maintenance anaerobic conditions and immediate distillation of the fermented product.

Studies carried out by Aguilar et al. (2015) showed that nutritional value of S. cerevisiae varies depending on the substrate used for its growth and the industrial technology to which this yeast is subjected. Once S. cerevisiae is recovered in the distilleries, its composition depends on the type and quality of final molasses used as a substrate in the process (Estévez 2015); on the specific production conditions and the operating regime developed in each alcohol factory (Machín et al. 2016).

Results of this research could be a direct consequence of the production process that is carried out in each alcohol industry. Differences according to technical constructive state and equipment of each factory determine the quality of the cream obtained during the process.

Regardless of the distillery of origin, composition of creams under study was similar. An important aspect to consider is that all Cuban distilleries work with a defined technology, the same strain of S.cerevisiae and similar raw materials on an industrial scale (molasses). Therefore, yeast cream generated from national alcohol production practically does not vary in composition.

Fermentation process in the industry of alcohol production and its by-products constitutes one of the most important sources of S. cerevisiae. The main thing about these creams is the high content of yeasts (70%) in their composition (Valdés et al. 2015). In Cuba, its recovery is limited to the surplus that remains in the bottom of fermenters, an issue that affects the amount of available cream. Itsuse would not be efficient as animal feed, since it is produced in discrete volumes (20,000 t/year) at national scale (Machín et al. 2016). Currently, several distilleries are in operation in the country. However, advances in industrial biotechnology offer potential opportunities for the use of these agro-industrial residues with aggregated value from a nutritional point of view and a better effect on animal health and physiology.

S. cerevisiae creams, after being treated in a biotechnological process with microbial enzymes produced by Bacillus subtilis (hydrolytic agent), are transformed into a valuable product (PROBIOLEV®) with prebiotic and probiotic properties (Pérez et al. 2006). Coming from the sugar industry, they are a low-cost national raw material, a more valid alternative to the use of antibiotic additives, and an economically profitable way to expand their use profile.

PROBIOLEV® is a complete biopreparation, which main focus is on the components of cell wall hydrolysis of S. cerevisiae (glucan and mannan oligosaccharides), due to its history as a growth promoter prebiotic in animals (Jahanian and Ashnagar 2015 and Lourenço et al. 2016), and B. subtilis viable cells and their endospores, a probiotic microorganism that favors the increase of beneficial intestinal biota and activates the immune response (Díaz et al. 2017 and Milián et al.2019). Due to its composition, PROBIOLEV® is considered as an additive with a high potential for symbiotic activity.

Pérez et al. (2005), Piad et al. (2006) and Pérez et al. (2015) demonstrated that with the application of PROBIOLEV® to animal diets, the beneficial microbiota is promoted, together with its powerful defensive effect against colonization of pathogens and opportunists, it reinforces the function of the intestinal barrier. According to the cited authors, this biological preparation caused greater efficiency in feed conversion, body weight uniformity and productive yields of birds that consumed it.

Low production cost of PROBIOLEV® and the high availability of its raw material (waste obtained from alcohol and derivatives production industry, rich in S. cerevisiae), which constitutes an environmental pollutant, are the basis for the economic feasibility of the use of this additive. In addition, the increase of production levels of meat, milk and eggs in animals of zootechnical interest, due to the decrease of pathogenic microbial concentration (Piad et al. 2006 and Rodríguez et al. 2015).

Distillery creams have been used directly in pig diets for years. Solano et al. (2012) managed to replace 30% of the protein provided by soy bean meal with this S. cerevisiae cream, besides supplying B vitamins (except B-12) from the pig premix, without affecting the characteristics of the productive performance of these animals. However, due to the amounts of these components (proteins and vitamins) in the product (cream) and in the diets, their effects could be less important when compared to the possibility of expanding the activity of oligosaccharides of glucans, mannans and B. subtilis cells and their endospores.

However, to ensure that PROBIOLEV® has biologically stable properties for animal development and growth, it is necessary to carry out chemical analysis and microbiological quality studies, since one of the fundamental raw materials for its preparation, which is the cream of S cerevisiae, does not come from the same source.

Table 3 shows the results of the microbiological characterization of creams under study. The populations of the different microorganisms analyzed were determined to be within the normal ranges defined by the NC-ISO for microbiology studies of food intended for human and animal consumption. This fact corroborates the absence of viable contaminants in this type of product. No noticeable alterations were found, regardless of the distillery from which the creams came from.

Table 3 Microbiological analysis of different Saccharomyces cerevisiae creams 

Microbiological tests Cuban distilleries
José A. Echeverría Jesús Rabí Héctor Molina Heriberto Dukuesne Antonio Sánchez
Recount of Bacillus spp.(CFU mL-1) - - - - -
Recount of viable yeasts (CFU mL-1) 103 <103 103 <103 <103
Recount of total and fecal coliforms Negative Negative Negative Negative Negative
Recount of Pseudomonas aeruginosa Negative Negative Negative Negative Negative
Recount of Staphylococcus aureus Negative Negative Negative Negative Negative
Recount of Bacillus cereus Negative Negative Negative Negative Negative
Counting of Salmonella in 25 mL No presence No presence No presence No presence No presence

During the packaging and transportation of creams from different provinces, aseptic conditions were favorable for the non proliferation of foreign microbial agents during the storage period (10 days, under environmental conditions) until their processing. The extreme conditions of the medium (acidic pH) decrease the possibilities of growth and development of harmful germs in creams. These characteristics allow their use and storage in production places where there are no possibilities of conservation at low temperatures.

In addition to the chemical and microbiological study, an organoleptic analysis was performed. Results showed normal, brown coloration, characteristic odor, slightly alcoholic, with an acid tendency, and normal appearance. This means that there was no presence of foreign particles or signs of contamination.

From the obtained results, it is concluded that the different S. cerevisiae creams, without considering the distillery of origin, have chemical and microbiological characteristics that favor their use for producing the symbiotic additive PROBIOLEV®, biotechnologically. Currently, this additive is neither produced nor applied on a production scale. However, the study carried out is very important because it, undoubtedly, enables the rational and feasible use of recycling S. cerevisiae yeast cream, made from a polluting agro-industrial residue with a harmful effect on the environment.


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Received: December 23, 2019; Accepted: June 03, 2020


Declaración de conflicto de intereses: Los autores declaran no presentar conflicto de intereses

Contribución de los autores: Los autores declaran presentar contribución igualitaria en la concepción de la investigación, obtención y procesamiento de los datos y redacción del documento

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