RESUMEN
Sugarcane-based fermentation is an essential process for different sectors of economic importance, such as the food industry with fermented and distilled beverages. However, this process can suffer from high contamination by wild yeasts and bacteria, especially lactic acid bacteria (LAB). This makes it necessary to use decontamination strategies and search for new methods that have a low environmental impact and contribute to the production of organic products. Among the options, oregano and thyme essential oils stand out for their antibacterial compounds. The aim of this study was to use oregano and thyme essential oils as natural antimicrobials in the alcoholic fermentation of sugar cane juice. Initially, the minimum inhibitory concentration of the essential oils in the fermentation was assessed through turbidity in the sensitivity test, which allowed us to determine which concentrations of essential oils would inhibit the contaminants, 3 morphologically selected LAB strains, as well as assessing the viability of CA-11. For LAB, 3 concentrations of each essential oil were tested, ranging from 0.1 to 0.4 µl/mL, while for CA-11 it was 0.06, to 0.1 µl/mL. The results indicated a maximum total value of essential oils per ml of 0.06 µl. Based on this result, a 24-1 fractional factorial was established, with 8 conditions +3 central points, with 4 variables, oregano essential oil (0, 0.03 and 0.06 µl/ml), thyme (0, 0.03 and 0.06 µl/ml), initial soluble solids (14, 16 and 18°Brix) and initial yeast concentration (2.5, 3 and 3.5 g/l), with the temperature set at 32 °C for a period of 12 h. The results showed that the center point condition with 0.03 µl/ml of oregano EO, 0.03 µl/ml of thyme controlled the proliferation of contaminating bacteria compared to the control condition. In the experimental validation, the treatment with essential oils had a lower final population of LAB (5.95 log) than the final population of the control treatment (6.53 log), and it was also observed that the treatment with EOs had an alcohol production around 3 % higher than the treatment without antimicrobials. The experimental validation phase confirmed the synergistic action of oregano and thyme essential oils in controlling the proliferation of contaminating bacteria. In conclusion, it was possible to determine the synergistic antimicrobial action of essential oils against LAB during alcoholic fermentation based on organic sugar cane.
Asunto(s)
Fermentación , Lactobacillales , Pruebas de Sensibilidad Microbiana , Aceites Volátiles , Origanum , Thymus (Planta) , Aceites Volátiles/farmacología , Lactobacillales/metabolismo , Lactobacillales/efectos de los fármacos , Thymus (Planta)/química , Origanum/química , Antiinfecciosos/farmacología , Antibacterianos/farmacología , Microbiología de AlimentosRESUMEN
The aim of this research was to study the production of humic acids (HA) by Trichoderma reesei from empty fruit bunches (EFBs) of palm oil processing, with a focus on the effects of lignocellulosic content and residual lipids. EFBs from two different soils and palm oil producers were previously characterized about their lignocellulosic composition. Submerged fermentations were inoculated with T. reesei spores and set up with or without residual lipids. The results showed that the soil and the processing for removal of the palm fresh fruits were crucial to EFB quality. Thus, EFBs were classified as type 1 (higher lignocellulosic and fatty acids composition similar to the palm oil and palm kernel oil) and type 2 (lower lignocellulosic content and fatty acids composition similar to palm oil). Despite the different profiles, the fungal growth was similar for both EFB types. HA production was associated with fungal growth, and it was higher without lipids for both EFBs. The highest HA productivity was obtained from type 1 EFB (approximately 90 mg L-1 at 48 h). Therefore, the lignocellulosic composition and the nature of the residual lipids in EFBs play an important role in HA production by submerged fermentation.
Asunto(s)
Fermentación/efectos de los fármacos , Sustancias Húmicas/microbiología , Lignina/farmacología , Lípidos/farmacología , Aceite de Palma/química , Trichoderma/efectos de los fármacos , Trichoderma/metabolismo , Inmersión , Lignina/químicaRESUMEN
The aim of this work was to study oxygen transfer as a function of the initial moisture content in solid-state cultivation under controlled moisture conditions. The use of controlled moisture conditions prevents drastic changes in the medium during cultivation, allowing the use of a pseudo-steady-state model to estimate the overall oxygen mass transfer coefficient (K L a) in the biofilm around the solid particles. Drechslera (Helminthosporium) monoceras, an aerobic mold that produces allergenic proteins, was cultured on wheat bran in a packed bed column bioreactor. The bed height (30 mm) and air flow rate (0.4 L/min) were selected to implement moisture control. The results show that there is an optimal moisture content (35 %) at which a lower biofilm thickness and packing of the bed improves K L a. However, a higher biomass growth was obtained at 45 % moisture. The different patterns of biomass growth demonstrate the importance of the balance between aerial and film growth in solid-state cultivation. These results contribute to the understanding of oxygen transfer in solid fermentation, optimization of processes, and production of allergen extracts from D. (Helminthosporium) monoceras biomass.
Asunto(s)
Oxígeno/química , Agua/química , Reactores Biológicos , Helminthosporium/citología , Triticum/químicaRESUMEN
The strain Bacillus iso 1 co-produces the lipopeptide iturin A and biopolymer poly-γ-glutamic acid (γ-PGA) in solid-state fermentation of substrate consisting of soybean meal, wheat bran with rice husks as an inert support. The effects of pressure drop, oxygen consumption, medium permeability and temperature profile were studied in an aerated packed bed bioreactor to produce iturin A, diameter of which was 50 mm and bed height 300 mm. The highest concentrations of iturin A and γ-PGA were 5.58 and 3.58 g/kg-dry substrate, respectively, at 0.4 L/min after 96 h of fermentation. The low oxygen uptake rates, being 23.34 and 22.56 mg O2/kg-dry solid substrate for each air flow rate tested generated 5.75 W/kg-dry substrate that increased the fermentation temperature at 3.7 °C. The highest pressure drop was 561 Pa/m at 0.8 L/min in 24 h. This is the highest concentration of iturin A produced to date in an aerated packed bed bioreactor in solid-state fermentation. The results can be useful to design strategies to scale-up process of iturin A in aerated packed bed bioreactors. Low concentration of γ-PGA affected seriously pressure drop, decreasing the viability of the process due to generation of huge pressure gradients with volumetric air flow rates. Also, the low oxygenation favored the iturin A production due to the reduction of free void by γ-PGA production, and finally, the low oxygen consumption generated low metabolic heat. The results show that it must control the pressure gradients to scale-up the process of iturin A production.
Asunto(s)
Bacillus/metabolismo , Reactores Biológicos , Lipopéptidos/biosíntesis , Péptidos Cíclicos/biosíntesis , Fibras de la Dieta , Fermentación , Oryza/química , Ácido Poliglutámico/biosíntesis , Glycine max/químicaRESUMEN
The spleen is a critical organ in defence against haemoparasitic diseases like babesiosis. Many in vitro and ex vivo studies have identified splenic cells working in concert to activate mechanisms required for successful resolution of infection. The techniques used in those studies, however, remove cells from the anatomical context in which cell interaction and trafficking take place. In this study, an immunohistological approach was used to monitor the splenic distribution of defined cells during the acute response of naïve calves to Babesia bovis infection. Splenomegaly was characterized by disproportionate hyperplasia of large versus small leucocytes and altered distribution of several cell types thought to be important in mounting an effective immune response. In particular, the results suggest that the initial crosstalk between NK cells and immature dendritic cells occurs within the marginal zone and that immature dendritic cells are first redirected to encounter pathogens as they enter the spleen and then mature as they process antigen and migrate to T-cell-rich areas. The results of this study are remarkably similar to those observed in a mouse model of malarial infection, suggesting these dynamic events may be central to the acute response of naïve animals to haemoparasitic infection.
Asunto(s)
Babesia bovis/inmunología , Babesia bovis/parasitología , Babesiosis/inmunología , Babesiosis/parasitología , Enfermedades de los Bovinos/inmunología , Enfermedades de los Bovinos/parasitología , Células Dendríticas/inmunología , Células Dendríticas/parasitología , Inmunofenotipificación , Células Asesinas Naturales/inmunología , Células Asesinas Naturales/parasitología , Bazo/inmunología , Bazo/parasitología , Esplenomegalia/inmunología , Esplenomegalia/parasitología , Enfermedad Aguda , Animales , Antígenos de Protozoos/inmunología , Babesia bovis/ultraestructura , Babesiosis/veterinaria , Bovinos , Enfermedades de los Bovinos/fisiopatología , Recuento de Células , Proliferación Celular , Inmunohistoquímica , Inmunofenotipificación/veterinaria , Espectroscopía de Resonancia Magnética , Masculino , Tamaño de los Órganos , Bazo/fisiopatología , Esplenomegalia/veterinariaRESUMEN
Over the past several years, innate immunity has been recognized as having an important role as a front-line defense mechanism and as an integral part of the adaptive immune response. Innate immunity in cattle exposed to hemoparasites is spleen-dependent and age-related. In this review, we discuss general aspects of innate immunity and the cells involved in this aspect of the response to infection. We also provide examples of specific splenic regulatory and effector mechanisms involved in the response to Babesia bovis, an important tick-borne hemoparasitic disease of cattle. Evidence for the regulatory and effector role of bovine splenic monocytes and DC both in directing a type-1 response through interaction with splenic NK cells and γδT-cells will be presented.
Asunto(s)
Enfermedades de los Bovinos/inmunología , Bovinos/inmunología , Inmunidad Innata , Parasitemia/veterinaria , Bazo/inmunología , Animales , Babesia bovis , Babesiosis/inmunología , Bovinos/genética , Enfermedades de los Bovinos/genética , Citocinas/biosíntesis , Citocinas/genética , Células Dendríticas/inmunología , Células Asesinas Naturales/inmunología , Modelos Inmunológicos , Células Mieloides/inmunología , Óxido Nítrico/biosíntesis , Parasitemia/genética , Parasitemia/inmunología , ARN Mensajero/genética , Bazo/citología , Subgrupos de Linfocitos T/inmunologíaRESUMEN
Early interactions of innate immune cell populations, such as dendritic cells (DC) and natural killer (NK) cells, can affect the ability of the acquired immune response to control infection of intracellular microorganisms. In this study, we investigated the activation of bovine NK cells by CD13(+) splenic DC stimulated with either Mycobacterium bovis BCG or Babesia bovis merozoites. Splenic DC were used either immediately after selection (cytokine(-)) or after exposure to GM-CSF, IL-4 and Flt3L for 72 h (cytokine(+)). Phenotypic analyses showed up-regulation of MHCII, CD80 and CD86 on cytokine(+) DC when compared to cytokine(-) DC. Purified NK cells (CD335(+)CD3(-)CD2(+/-)CD8alpha(+/-)) were co-cultured with microbial-exposed cytokine(-) DC or cytokine(+) DC in either transwell or cell-to-cell format and NK cell IFN-gamma production and cytotoxicity were assessed. NK cell IFN-gamma production was dependent on cell-to-cell contact. Microbial-stimulated cytokine(+) DC induced significantly more IFN-gamma production from NK cells than cytokine(-) cells. In contrast, cytotoxicity and perforin up-regulation were more pronounced in NK cells cultured with cytokine(-) DC than cytokine(+) DC. Therefore, activation of bovine NK cells by microbial-stimulated CD13(+) splenic DC is influenced by the maturation state of the DC suggesting different roles for the splenic DC during disease-induced maturation.
Asunto(s)
Babesia bovis/inmunología , Células Dendríticas/inmunología , Interferón gamma/biosíntesis , Células Asesinas Naturales/inmunología , Mycobacterium bovis/inmunología , Animales , Antígeno B7-1/inmunología , Antígeno B7-2/inmunología , Bovinos , Técnicas de Cocultivo , Citotoxicidad Inmunológica , Células Dendríticas/microbiología , Citometría de Flujo/veterinaria , Factor Estimulante de Colonias de Granulocitos y Macrófagos/inmunología , Antígenos de Histocompatibilidad Clase II/inmunología , Interferón gamma/inmunología , Interleucina-4/inmunología , Células Asesinas Naturales/microbiología , Masculino , Proteínas de la Membrana/inmunologíaRESUMEN
Both bovine peripheral blood monocyte-derived dendritic cells (DC) and myeloid DC from afferent lymph have been described, but resident DC from other bovine tissues have not been fully characterized. The spleen as a secondary lymphoid organ is central to the innate and acquired immune response to various diseases particularly hemoprotozoan infections like babesiosis. Therefore, we developed methods to demonstrate the presence of myeloid DC from the spleen of cattle and have partially characterized a DC population as well as another myeloid cell population with monocyte characteristics. The phenotypic profile of each population was CD13+CD172a+/-CD14-CD11a-CD11b+/-CD11c+ and CD172a+CD13+/-CD14+CD11a-CD11b+/-CD11c+, respectively. The CD13+ population was found exclusively in the spleen whereas the CD172a+ population was present at the same percentage in the spleen and peripheral blood. CD13+ cells developed a typical veiled appearance when in culture for 96 h. The two cell populations differed in their ability to produce nitric oxide and had a different pattern of cytokine mRNA when stimulated with Mycobacterium bovis BCG or Babesia bovis merozoites. The data demonstrate the presence of a myeloid splenic DC with attributes consistent with an immature status.