ABSTRACT: The present investigation aimed to evaluate the type of maintenance and the types of machinery in four sawmills in the city of Jaén, the evaluation was carried out through the methodology of direct observation information collection through the data collection sheet instrument, In turn, the type of machinery used in the first transformation sawmill work was identified, with the technical characteristics of each machinery usually consisting of a brushcutter, band saw, circular table saw and a planer. The type of sawmill was classified according to its daily production, being the sawmill the parral, Santa Rosa and Casa Blanca in the category of small and the sawmill the union of very small; process diagrams were also elaborated according to the classification, resulting in two process diagrams; and the classification of maintenance in the studied sawmills is preventive and corrective; It was also determined that it is business-oriented for the La Unión, Santa Rosa and Casa Blanca sawmills and for the El Parral sawmill it is classified as oriented to business-followers.

RESUMEN: La presente investigación tuvo como objetivo clasificar el tipo de mantenimiento y describir el tipo de maquinarias en cuatro aserraderos en la ciudad de Jaén, la evaluación se realizó mediante la metodología de recopilación de información de observación directa mediante el instrumento de ficha de recolección de datos, a su vez se identifico el tipo de maquinaria usada en los trabajos de aserrío de primera transformación, siendo las características técnicas de cada maquinaria conformado usualmente por una desbrozadora, sierra cinta, sierra circular de mesa y una cepilladora. Se clasificó el tipo de aserradero según su producción diaria, siendo el aserradero el parral, santa rosa y casa blanca en categoría de pequeño y el aserradero la unión de muy pequeño; también se elaboraron diagramas de procesos según la clasificación dando como resultado dos diagramas de procesos; y la clasificación del mantenimiento en los aserraderos estudiados es de tipo preventivo y correctivo; también se determinó que es orientado a los negocios para los aserraderos la Unión, Santa Rosa y Casa Blanca y para el aserradero el parral se clasifica en orientado a los negocios - seguidores.

Abstract The pandemic and the geopolitical conflict between Russia and Ukraine are events that have caused economic instability in Peru. Reason that was investigated on the analysis of the biological and chemical characteristics of cabbage fed with compost based on sugarcane residues. The objective was to analyze the physical, chemical and biological characteristics of cabbage from the adequate dose of compost based on sugarcane residues and distance between plants. It is based on the methodology applied with an experimental approach, for which the Completely Random Block Design with a 4x 2 factorial arrangement was used, which consisted of 3 blocks and 8 treatments that were the combination: F1 with 0, F2 with 8, T3 with 10 and F4 with 12 t/ha and spacing (D1) with 0.30 m between plants and 0.60 m between rows and (D2) with 0.35 m between plants and 0.60 m between rows. The physical characteristics of cabbage were evaluated and processed by analysis of variance, nutrient concentrations in leaves and stomatal density were analyzed. The results determined that T7 stood out in plant height with 41.88 cm, yield with 26.76 tn/ha and T6 in root length with 20.22 cm. In chemical analysis of leaves T1 stood out in nitrogen, phosphorus, potassium and T4 in calcium, magnesium and sulfur. In T7 stomata density with 977 stomata/mm2. It concludes that at an adequate dose and greater distance that T7 stands out in the concentration of nutrients that are within normal values and high density of stomata; Therefore, these characteristics influenced the optimal biochemical reactions, which obtained good development and yield that differed at 51.39% and 32.17% with respect to the controls T1 and T5.

Resumo A pandemia e o conflito geopolítico entre a Rússia e a Ucrânia são eventos que têm causado instabilidade econômica no Peru. Motivo que foi investigado na análise das características biológicas e químicas do repolho alimentado com composto à base de resíduos da cana-de-açúcar. O objetivo foi analisar as características físicas, químicas e biológicas do repolho a partir da dose adequada de composto à base de resíduos da cana-de-açúcar e distância entre plantas. Baseia-se na metodologia aplicada com uma abordagem experimental, para a qual foi utilizado o Delineamento de Blocos Completamente Aleatório com arranjo fatorial 4 x 2, que consistia em 3 blocos e 8 tratamentos que eram a combinação: F1 com 0, F2 com 8, T3 com 10 e F4 com 12 toneladas/ha e espaçamento (D1) com 0,30 m entre plantas e 0,60 m entre linhas e (D2) com 0,35 m entre plantas e 0,60 m entre linhas. As características físicas do repolho foram avaliadas e processadas por análise de variância, as concentrações de nutrientes nas folhas e a densidade estomática foram analisadas. Os resultados determinaram que T7 se destacou em altura de planta com 41,88 cm, produtividade com 26,76 tn/ha e T6 em comprimento de raiz com 20,22 cm. Na análise química das folhas T1 se destacou em nitrogênio, fósforo, potássio e T4 em cálcio, magnésio e enxofre. Em densidade de estômatos T7 com 977 estômatos/mm2. Conclui que em dose adequada e maior distância que T7 se destaca na concentração de nutrientes que estão dentro dos valores normais e alta densidade de estômatos; Portanto, essas características influenciaram nas reações bioquímicas ótimas, que obtiveram bom desenvolvimento e rendimentos que diferiram em 51,39% e 32,17% em relação aos controles T1 e T5.

Abstract We report on a functional Fabry-Perot mode interferometer and its application for absolute displacement sensing. The proposed device consists of two well-cleaved tips of standard optical fibers that were introduced into a microcapillary glass with an inner diameter of ∼ 125.5 um; one tip was stuck to the capillary by the application of an electric arc from a standard splice machine, while the other tip was free to be longitudinally moved. The transmission spectrum of the interferometric device exhibited an interferometric pattern due to the reflections of the fundamental mode on the two partial reflecting tip surfaces of the standard optical fibers. The period and the intensity level of the interference pattern depend strongly on the separation between the optical fiber tips caused by the displacement of the free optical fiber tip. This dependence allows for the use of either period or intensity changes for length displacement sensing interrogation. For the period interrogation, the length can be accurately calculated and measured by taking the Fast Fourier Transform (FFT) of the detected interference pattern. For intensity interrogation, a simple photodetector can determine the distance that separates the optical fiber tips.

Abstract In the province of Santiago de Cuba, Cuba, the COVID-19 epidemic has a limited progression that shows an early small-number peak of infections. Most published mathematical models fit data with high numbers of confirmed cases. In contrast, small numbers of cases make it difficult to predict the course of the epidemic. We present two known models adapted to capture the noisy dynamics of COVID-19 in the Santiago de Cuba province. Parameters of both models were estimated using the approximate-Bayesian-computation framework with dedicated error laws. One parameter of each model was updated on key dates of travel restrictions. Both models approximately predicted the infection peak and the end of the COVID-19 epidemic in Santiago de Cuba. The first model predicted 57 reported cases and 16 unreported cases. Additionally, it estimated six initially exposed persons. The second model forecasted 51 confirmed cases at the end of the epidemic. In conclusion, an opportune epidemiological investigation, along with the low number of initially exposed individuals, might partly explain the favorable evolution of the COVID-19 epidemic in Santiago de Cuba. With the available data, the simplest model predicted the epidemic evolution with greater precision, and the more complex model helped to explain the epidemic phenomenology.

ABSTRACT Introduction: Tobacco use is harmful to health, according to the World Health Organization (WHO) smoking is the cause of death for approximately 8 million people each year. Objective: The purpose of the research was to determine the factors associated with tobacco consumption in university students from Metropolitan Lima. Methods: The sample consisted of 447 students from different universities in Lima, a previously validated survey was applied: Fagerstrom test to measure tobacco consumption. Subsequently, the data was analyzed using distribution, frequency and contingency tables. In addition, regression statistical test was applied to obtain the prevalence ratios (PR) of the study variables in both bivariate and multivariate analyzes, with a 95% confidence interval (95% CI). Results: It was evidenced that there is a significant association between male sex and smoking (p = 0.01), with an RP = 1,67 and 95% CI = . It was also observed that having smoking parents was statistically associated with smoking in university students, with a value of p=0.00, and an RP=2,53 with a 95% CI = . No significant association was found between the variables age and social pressure. Conclusion: The variables sex and smoking parents have a significant association with tobacco consumption, emphasizing that both our family and academic environment deserve to be safe, healthy and free of tobacco smoke.

RESUMEN Introducción : El consumo de tabaco es perjudicial para la salud, según la Organización Mundial de la Salud (OMS) el tabaquismo es la causa de muerte de aproximadamente 8 millones de personas cada año. Objetivo : El propósito de la investigación fue determinar los factores asociados al consumo de tabaco en estudiantes universitarios de Lima Metropolitana. Métodos : La muestra estuvo conformada por 447 estudiantes de diferentes universidades de Lima, se aplicó una encuesta previamente validada: Test de Fagerstrom para medir el consumo de tabaco. Posteriormente los datos fueron analizados utilizando tablas de distribución, frecuencias y contingencia. Además, se aplicó la prueba estadística regresión para obtener las razones de prevalencias (RP) de las variables de estudio tanto en el análisis bivariado como en el multivariado, con un intervalo de confianza al 95% (IC al 95%). Resultados : Se evidenció que existe asociación significativa entre el sexo masculino y el hábito de fumar (p=0,01), con un RP = 1,67 e IC al 95% = (1,03 - 2,23). También se pudo observar que tener padres fumadores estuvo estadísticamente asociado al hábito tabáquico en los universitarios, con un valor de p=0,00, y un RP = 2,53 con IC al 95% = (1,62 - 3,52). No se encontró asociación significativa entre las variables edad y presión social. Conclusión : Las variables sexo y padres fumadores tienen asociación significativa con el consumo de tabaco enfatizando que tanto nuestro entorno familiar como académico merece ser seguro, saludable y libre del humo de tabaco.

RESUMEN La poda es un procedimiento que tiene el propósito de estimular el desarrollo de nuevas yemas, incrementar la floración y la producción de frutos. Se evaluó la calidad del grano en árbo- les con diferente intensidad de poda en zona de bosque húmedo tropical (bh-T) en el municipio de Chigorodó región de Urabá en Colombia, a 40 msnm, con temperaturas entre 21 y 34°C, con humedad relativa promedio del 80%. Se cuantificó el contenido de grasa y de minerales en granos de cacao fermentados y secos de los clones universales CCN-51 e ICS-95, los trata- mientos correspondieron a poda de altura (-h) donde se cortó el árbol a 4 m de altura; poda base (b) con corte a 4 m de altura y ramas secas y mal ubicadas, poda base menos 25 por ciento del área foliar (b-25% AF), poda base menos 50 por ciento AF (b-50%) y base menos 75 por ciento (b-75%) del dosel. La colecta de frutos se realizó en 3 épocas, 2, 3, y 8 meses después de la poda El tratamiento de poda no tuvo efecto significati- vo sobre el contenido de minerales en el grano de cacao, solamente la época de cosecha fue el factor que presentó significancia.

ABSTRACT The purpose of pruning is to stimulate the development of new buds, increase flowering, production, and the quality of fruits. The quality of cocoa beans from trees that were pruned at different levels was evaluated in tropical moist forest life zone (T-mf) in the municipality of Chigorodó, in the Urabá region in Colombia, at 40 m. altitude, with temperatures between 21 and 34°C, with 80% average relative humidity. The fat content and minerals in fermented and dried cocoa beans of the universal clones CCN-51 and ICS-95 were quantified. The pruning treatments were as follows to height pruning (-h) the tree was cut to 4 m height; base pruning (b) cut at 4 m height with dry and poorly located branches removed; base pruning minus 25 percent leaf área (b-25% LA), base minus 50 percent LA (b-50%) and base minus 75 percent LA (b-75%) of the canopy. The harvest was carried out in 3 seasons, 2, 3, and 8 months after pruning. The pruning treatment had no significant effect on the mineral content in the cocoa beans, however the harvest time was a significant factor.

Resumo Este trabalho avaliou o desempenho contra a corrosão de juntas soldadas dissimilares, utilizando aço carbono ASTM A 615 e aços inoxidáveis austeníticos AISI 304 como metais básicos, e como metal de enchimento eletrodo ER-309L, utilizando bisel único de 45 °. Metade dos corpos-de-prova foram submetidos a um processo de "manteiga" com eletrodo Inconel 182. Os resultados eletroquímicos mostram que, apesar dos defeitos apresentados na junta soldada, eles tendem a passivar em meio alcalino, sendo os corpos de prova com manteiga menos deteriorado pelo efeito da corrosão.

Abstract In this study, the corrosion performance of dissimilar welded joints between ASTM A615 and AISI 304 stainless steel with and without buttering using Inconel 182 was evaluated. In both cases, the filler metal was ER-309L and the base metals were prepared with a 45° single bevel. One half of the specimens were welded with “buttering” using Inconel 182. The electrochemical results showed that despite welding defects, the welded specimens formed a passive layer in alkaline environments. The specimens welded with buttering exhibited the best corrosion resistance and mechanical properties.

Resumen Este trabajo evaluó el desempeño frente a la corrosión de uniones soldadas disimiles, utilizando como metales base acero al carbono ASTM A 615 y acero inoxidable austenítico AISI 304, y como metal de aporte electrodo ER-309L, se utilizó bisel simple a 45°. La mitad de los especímenes fueron sometidos a un proceso de “mantequillado” utilizando electrodo Inconel 182. Los resultados electroquímicos muestran que, a pesar de los defectos presentados en la unión soldada, estas tienden a pasivarse en medio alcalino, siendo las probetas con mantequillado las menos deterioradas por efecto de la corrosión y su resistencia mecánica no se ve minimizada.

ABSTRACT Objective Estimate whether there is an association between the (CAG)n repeat in the ATXN2 gene in the Mexican population and type 2 diabetes mellitus (DM). Methods Epidemiological case-control study, including healthy people and diabetics. (CAG)n expansion was detected by end-point polymerase chain reaction (PCR). PCR outputs were analyzed by electrophoresis (PAGE 8%) and silver nitrate staining. Results (CAG)n nucleotide allele distribution in the study population was similar to that reported in central Mexico. The 22-repeat allele is the most frequent; however, there is an association with carriers of long repeats in the normal range with diabetes. Conclusions The results suggest that the (CAG)n repeat of the ATXN2 gene could be a causal factor for type 2 DM.

RESUMEN Objetivo Estimar si hay asociación del repetido (CAG)n del gen ATXN2 en población mexicana con diabetes mellitus (DM) tipo 2. Métodos Estudio epidemiológico de casos y controles. Se incluyeron personas sanas y personas diabéticas. La detección de la expansión (CAG)n se realizó por reacción en cadena de la polimerasa (PCR)-punto final. Los productos de PCR se analizaron mediante electroforesis (PAGE al 8%) y tinción con nitrato de plata. Resultados La distribución de alelos del trinucleótido (CAG)n en la población analizada resultó similar a la reportada en el centro del país. El alelo más frecuente es el de 22 repetidos; sin embargo, hay asociación con los portadores de los repetidos largos dentro del rango normal con diabetes. Conclusiones Los resultados sugieren que el repetido (CAG)n del gen de ATXN2 podría ser un factor causal de DM tipo 2.

RESUMO O mero, Epinephelus itajara , encontra-se criticamente ameaçado, resultado da pesca ilegal e destruição dos habitas. Filogeneticamente relacionadas a este táxon encontram-se garoupas que atualmente são intensamente pescadas no Atlântico Oeste. Apesar de leis mais restritivas aplicadas em alguns países, a captura ilegal com a descaracterização morfológica é uma prática comum que impossibilita a identificação correta da espécie permitindo que seja comercializada como garoupas, badejos ou chernes. A este respeito, técnicas moleculares representam ferramentas importantes para o monitoramento e fiscalização da pesca, provando ser essencial, na identificação forense de diversas espécies. Primers espécie-específicos foram desenvolvidos com base no gene Citocromo Oxidase subunidade I que aplicados em PCR-Multiplex possibilitam a identificação simultânea de nove espécies Epinephelidae: Epinephelus itajara , E. quinquefasciatus , E. morio , Hyporthodus flavolimbatus , H. niveatus , Mycteroperca acutirostris , M. bonaci , M. marginata e M. microlepis . A identificação via PCR multiplex de espécies de peixes ameaçadas e comercialmente importantes é um método rápido, prático, seguro e de baixo custo, que poderá ser útil o controle do uso e manejo sustentável de recursos pesqueiros.

ABSTRACT The Atlantic goliath grouper, Epinephelus itajara , is a critically endangered species, threatened by illegal fishing and the destruction of its habitats. A number of other closely related grouper species found in the western Atlantic are also fished intensively. While some countries apply rigorous legislation, illegal harvesting followed by the falsification of fish products, which impedes the correct identification of the species, is a common practice, allowing the catch to be marketed as a different grouper species. In this case, molecular techniques represent an important tool for the monitoring and regulation of fishery practices, and are essential for the forensic identification of a number of different species. In the present study, species-specific primers were developed for the Cytochrome Oxidase subunit I gene, which were applied in a multiplex PCR for the simultaneous identification of nine different species of Epinephelidae: Epinephelus itajara , E. quinquefasciatus , E. morio , Hyporthodus flavolimbatus , H. niveatus , Mycteroperca acutirostris , M. bonaci , M. marginata , and M. microlepis . Multiplex PCR is a rapid, reliable and cost-effective procedure for the identification of commercially-valuable endangered fish species, and may represent a valuable tool for the regulation and sustainable management of fishery resources.

OBJECTIVE:To evaluate prevalence of cardiovascular risk among adults 40 years and older using population-based samples from six Central American countries. METHODS: Risk factors were derived from a multi-national cross-sectional survey implemented in 2003-2006, which included a sample of 4 202 participants aged 40 years and older. Charts produced by the World Health Organization and the International Society of Hypertension for the Region of the Americas sub-region B were used to predict risk on the basis of factors including age, sex, blood pressure, total serum cholesterol, smoking status, and diabetes status. RESULTS: Overall, 85.9% of the population was classified as having < 10% risk for cardiovascular events during the following ten years. The likelihood of being in this risk group decreased with age in both males and females. Four percent of respondents were identified as having > 20% risk. More than 75% of those with a 30-40% risk had previously been identified by health services, and an additional 23% were identified during the study, suggesting they could be diagnosed by opportunistic screening for diabetes, hypertension and hypercholesterolemia. Results of bivariate analysis showed that respondents who were male, older, obese and/or less educated had higher risk for cardiovascular events, but a multivariate analysis including education indicated highest risks for older, obese, and less educated females. CONCLUSIONS: Measuring cardiovascular disease risk identifies most cases of (or at risk for) diabetes, hypertension and hypercholesterolemia among adults 40 years and older. This strategy can facilitate implementation of control programs and decrease disabilities and premature mortality.

RESUMEN OBJETIVO:Evaluar la prevalencia del riesgo de padecer enfermedades cardiovasculares en adultos de 40 años de edad o mayores mediante el uso de muestras poblacionales obtenidas de seis países de América Central. MÉTODOS: Se tomaron los factores de riesgo de una encuesta transversal multinacional realizada entre 2003 y 2006, que incluyó una muestra de 4 202 participantes de 40 años de edad o mayores. Se usaron gráficos producidos por la Organización Mundial de la Salud y la Sociedad Internacional para la Hipertensión de la Región de las Américas, subregión B, para predecir el riesgo sobre la base de factores como la edad, el sexo, la presión arterial, las concentraciones totales de colesterol sérico, y la situación con respecto al tabaquismo y la diabetes. RESULTADOS: En términos generales, 85,9% de la población quedó clasificada en el grupo con un riesgo menor de 10% de sufrir episodios cardiovasculares en el transcurso de los 10 años siguientes. La probabilidad de pertenecer a este grupo de riesgo disminuyó con la edad, tanto en los hombres como en las mujeres. Se determinó que 4% de los encues-tados tenían un riesgo mayor de 20%. Más de 75% de los que tenían un riesgo de 30% a 40% ya habían sido identificados por los servicios de salud y otro 23% fue identificado durante el estudio, lo cual indica que los diagnósticos pueden hacerse mediante un tami-zaje oportunista para la detección de diabetes, hipertensión e hipercolesterolemia. Según los resultados del análisis bivariado, los entrevistados de sexo masculino, de edad más avanzada, obesos o con poca escolaridad tenían un mayor riesgo de sufrir episodios cardiovasculares, pero un análisis multivariado que abarcó el nivel educativo reveló que los riesgos más altos los tienen las mujeres mayores, obesas y con poca instrucción. CONCLUSIONES: El cálculo del riesgo cardiovascular permite identificar la mayoría de los casos (o personas con riesgo de presentar) diabetes, hipertensión e hipercolesterolemia en adultos de 40 años de edad o mayores. Esta estrategia puede facilitar la puesta en práctica de los programas de control, así como reducir la discapacidad y la mortalidad prematura.

Neste trabalho foi realizado um estudo das propriedades elétricas de blocos varistores à base de SnO2. Foram avaliadas a não linearidade destas cerâmicas por meio da caracterização tensão-corrente, bem como a altura, largura e os portadores de cargas por espectroscopia de impedância, além das energias de ativação. Os valores de α foram relativamente baixos sendo o maior valor de 6,3 para o sistema 98,65%SnO2.1,00%Co2O3.0,05%Nb2O5.0,05%Cr2O3.0,25%Pr2O3 (SCNCrPr). O sistema 98,65%SnO2.1,00%Co2O3.0,05%Nb2O5. 0,05%Cr2O3.0,25%La2O3 (SCNCrLa) apesar de apresentar um tamanho médio de grão pequeno 1,66 μm, possuiu um valor muito baixo de Er, o que pode está associado a não formação de barreiras efetivas na região de contorno de grão, gerando uma corrente de fuga elevada da ordem de 230 μA.

This paper reports on a study of the electrical properties of SnO2-based varistor blocks. The nonlinearity of these ceramics was evaluated based on their voltage-current characteristics, while the height, width and charge carriers were evaluated by impedance spectroscopy and activation energies. The α values were relatively low, with the SCNCrPr system showing the highest value: 6.3. Although the average grain size of the SCNCrLa system was small, i.e., 1.66 μm, its Er value was very low, which may be attributed to the non-formation of effective barriers in the grain boundary region, thus generating a high leakage current in the order of 230 μA.

A 39 year old female presented with a multifocal lesions in the skull, at the frontal right and parietal left. We performed bilateral craniectomies guided with navigation, and the bone defects were repaired with titanium mesh. The pathological examination reported intraosseous cavernous hemangioma in both lesions. Follow up of six months without any complication or recurrence and good cosmetic outcome.

Presentamos el caso clínico de una paciente de 39 años de edad quien presenta dos tumoraciones en cráneo a nivel frontal derecho y parietal izquierdo, que fueron resecadas en bloque mediante craniectomías guiadas por navegación. El defecto óseo fue reconstruido con mallas de titanio. El reporte histopatológico fue de hemangioma óseo en ambas lesiones. El seguimiento a 6 meses posterior a la cirugía sin evidencia de recurrencia y con un resultado cosmético satisfactorio.

Este trabajo tiene como objetivo presentar el desempeño de un controlador basado en redes neuronales B-spline que regula el aporte de potencia reactiva de las máquinas síncronas. Debido a que los sistemas de potencia operan con parámetros no estacionarios y configuración cambiante, es preferible utilizar esquemas de control adaptativos. La tecnología de control debe asegurar su desempeño en términos de condiciones operativas prácticas de los sistemas de potencia, que considere la diversidad de cargas conectadas a la red y maximice la disponibilidad de recursos. La red neuronal B-spline es una herramienta conveniente para implementar el control adaptativo de voltaje, con la posibilidad de llevar a cabo ésta tarea en-línea considerando las no linealidades del sistema. El despacho de potencia reactiva se basa en la premisa de que cada máquina debe aportar en proporción a su capacidad nominal de operación. La aplicabilidad de la propuesta se demuestra mediante simulación en un sistema de potencia multimáquinas.

This paper's aim is to present the performance of a B-spline neural network controller to regulate the reactive power provision from synchronous machines. Due to the fact that power systems work with non-stationary parameters and changing settings, adaptive control schemes are preferred. Control technology must ensure its performance in terms of power system's operation to address the diversity of loads and the optimal utilization of the available resources. The B-spline neural network is an efficient tool to implement the adaptive control voltage, with the possibility of carrying out this task on-line taking into account the systems' non-linearities. The reactive power dispatch is based on the premise that each machine must provide a proportion according to its nominal operating capacity. The applicability of the proposal is demonstrated by simulation on a 9-buses 3-machines power system.

In this communication, we document the technical feasibility of elaboration of two added value products from goat whey: (a) freeze-dried protein and (b) freeze-dried probiotic biomass of Lactobacillus casei. Results from goat milk whey ultrafiltration experiments are presented, from which high protein/lactose ratio protein is recovered. In its lyophilized form, this protein presents superior solubility characteristics with respect to analogous commercial products. The ultrafiltration permeate was utilized as growth culture medium for the probiotic microorganism L. casei. Results from batch and fed-batch fermentation experiments are reported. The growth kinetics of L. casei in de-proteinized goat milk whey is analyzed. From batch experiments, a kinetic characterization is conducted. A strong inhibition of biomass growth by lactic acid production is observed. Fed-batch strategies resulted in higher average productivities, lower residual substrate concentrations, and higher product viable counts than batch strategies.

En este trabajo se documenta la factibilidad técnica de obtención de dos productos de valor agregado a partir de suero de leche de cabra: (a) proteína liofilizada y (b) biomasa probiótica liofilizada de Lactobacillus casei. Se presentan resultados de experimentos de ultrafiltración de suero de leche de cabra (SLC), del cual se retiene proteína con una alta relación proteína/lactosa. En su forma liofilizada, esta proteína presentó características de solubilidad superiores a productos comerciales similares. El permeado resultante del ultrafiltrado de SLC fue utilizado como medio de cultivo para el crecimiento del microorganismo probiótico L. casei. Se reportan resultados de experimentos de fermentación de suero de leche por lote y lote alimentado para la producción de biomasa. La cinética de crecimiento de L. casei en SLC desproteinizado no suplementado es analizada a partir de datos de experimentos por lotes. Se observa un marcado efecto inhibitorio del crecimiento bacteriano asociado a la producción de ácido láctico. Las estrategias por lote alimentado aquí reportadas resultan en productividades superiores, concentraciones de sustrato residual menores y viabilidades más altas del producto respecto a procesos por lote.