Production of an extracellular keratinase from Chryseobacterium sp. growing on raw feathers

The strain Chryseobacterium sp. kr6 shown to be useful for biotechnological purposes such as hydrolysis of poultry feathers and de-hairing of bovine pelts. The effect of temperature, initial pH and media composition on protease production by this keratinolytic strain was studied. The enzyme was produced between 25 and 37\ub0C, with maximum activity and yield at 30\ub0C. When protease production was tested in media with different initial pH, maximum activity was observed when cultivation was carried out at 30\ub0C and initial pH ranging from 6.0 to 8.0. Higher activity was observed when feathers or feather meal were used as growth substrates, followed by soybean meal. The addition of carbohydrates or surfactants to feather broth resulted in decrease in keratinolytic activity

Production of crystallized fruit from watermelon rind

El presente trabajo tuvo como objetivo el aprovechamiento de las cascaras de sandía en la elaboración de productos cristalizados. Para esto fue eliminada la cutícula verde externa de la cascara, cortadas en forma de cubo de aproximadamente 7 mm de lado, escaldado con agua en su temperatura de ebullición utilizando 0, 5 ó 10 minutos y dejados inmersos en una solución de cloruro de sodio. Posteriormente fueron sometidas a concentraciones crecientes de soluciones de sacarosa (30 a 72 °Brix) y deshidratadas en un secador a diferentes temperaturas (40, 60 y 80 °C). Los diferentes tratamientos fueron evaluados por un panel sensorial. El diseño experimental empleado fue el de bloques completos aleatorios y los resultados del análisis sensorial fueron evaluados por la prueba de comparación de medias de Tukey. Fue constatado que el tratamiento con mayor aceptabilidad, por parte del panel sensorial, fue la que había sido sometida a un escaldado de 5 minutos y deshidratado a 60 °C, cuyos valores de intensidad para la apariencia, sabor y gomosidad estuvieron entre 6 y 7.The aim of this work was to produce crystallized fruit from watermelon rind. The following procedure was developed: the outer peel was removed; the material was sliced into 7 mm cubes, blanched for, 0, 5 and 10 minutes, and then treated with 10% sodium chloride solution. This product was treated with solutions of sucrose (30 to 72 °Brix), and dried in a hot air dryer at different temperatures (40, 60 and 80 °C). Products were then analyzed by a sensory panel. The experimental design used was randomized blocks and the results were analyzed by the Tukey's test. The best acceptance of the sensory panel was for the product obtained by 5 minutes blanching followed by drying at 60 °C, whose intensity values for appearance, flavor and gummosis were between 6 and 7

Detection of Paenibacillus larvae by Real-Time PCR

Background:  : : is the agent of the American Foulbrood disease (AFB), which may determine the death of the hive. The detection strategy for its diagnosis is based on clinical signs of disease, isolation and identification of P. larvae, which usually employs microbiological and biochemical methods. Recently, molecular methods based on analysis of 16S rDNA by conventional PCR have been adopted, providing greater security and analytical speed. The rapid diagnosis is important to minimize economic losses and assess routes of spread of the pathogen. Despite the strong existing sanitary control, P. larvae was recently identified in the Brazilian states of Rio Grande do Sul and Paraná. After that, outbreaks have been reported in neighboring countries. This investigation was conducted to develop a protocol for detection of P. larvae by real-time PCR, allowing the reduction in the time of diagnosis, without loss of robustness found in the conventional PCR methods. Materials, Methods & Results: Twenty-nine (29) P. larvae strains were evaluated by real-time PCR using SYBR Green. The primers Pltr-F/R were designed according to the sequence X60619 of 16S rDNA gene published in GenBank, to amplify a fragment of 74 base pairs. The target gene is highly conserved and specific to P. larvae. The amplification conditions consisted of 1 cycle of 50°C for 2 minutes and 1 cycle of 95°C for 10 minutes, followed by 40 cycles of 95°C for 15 seconds and 60°C for 1 minute. The fluorescence was monitored during the annealing at 60°C. The reactions were conducted in a 7500 Real Time PCR System equipment, using SYBRGreen PCR master mix (both Applied Biosystems), containing 2X Platinum SYBRGreen qPCR Supermix-UDG. The concentrations of primers were 1, 10 and 100 mM, and different concentrations of MgCl2 (0,0mM de MgCl2, 1.0mM de MgCl2 , 2.0mM de MgCl2 and 3.0mM de MgCl2) were tested, with a final volume of 50mL; 25mL and 15mL, containing a 5mL sample. The analysis of the melting curve was made based on a 95°C for 15 seconds and 60°C for 20 seconds and one cycle with temperature ranging between 60°C and 95°C for 20 minutes. The best results of sensitivity and specificity in the reaction with SYBR Green were obtained with primer concentration set as 100 mM. The different concentrations of MgCl2 tested did not affect the performance of the reaction. No amplification was observed with DNA obtained from Paenibacillus alvei or Bacillus species. The limit of detection was set as 6 pg of DNA template. The regression analysis of the CT values of the PCR products showed a linear relationship between the initial amounts of DNA template and the values of CT (R2 = 0.9982), indicating that the test is highly precise. Discussion: The protocol developed allowed the unequivocal identification of P. larvae, as all strains were detected by this approach. The amplification of the expected 16S rDNA gene fragment was verified by amplification with the primers Pltr F/R only for chromosomal DNA of P. larvae. In addition, the amplicon specificity was verified by sequencing and no amplification was observed when the primers were tested with DNA from other bacterial species. The protocol developed in this study proved to be sensitive and specific, providing a rapid and accurate diagnostic tool. The results showed that the analysis by real-time PCR of partial 16S rDNA gene of P. larvae represents an important alternative for rapid diagnosis of AFB disease. The use of this methodology may represent an advance for rapid confirmation of the presence of this bacterium, what will allow the adoption of control measures against AFB, which can avoid its spreading in Brazilian territory.Paenibacillus larva

Natural pigments of microbial origin

The world demands new solutions and products to be used as dyes for industrial applications. Microbial pigments represent an eco-friendly alternative as they can be produced in large amounts through biotechnological processes and do not present environmental risks, as they are easily decomposable. Moreover, some of these metabolites are recognized for their biological activities, which qualify them for potential uses as food colorants and nutraceuticals, protecting against degenerative diseases related with oxidative stress. Because of their genetic simplicity as compared with plants, microorganisms may be a better source to understand biosynthetic mechanisms and to be engineered for producing high pigment yields. Despite the origin of the pigmented microorganism, it seems very important to develop protocols using organic industrial residues and agricultural byproducts as substrates for pigment production and find novel green strategies for rapid pigment extraction. This review looks for the most recent studies that describe microbial pigments from microalgae, fungi, and bacteria. In particular, the underexploited tools of omics science such as proteomics and metabolomics are addressed. The use of techniques involving mass spectrometry, allows to identify different protein and metabolite profiles that may be associated with a variety of biotechnologically-relevant pathways of pigment synthesis

Development and characterization of innovative polymeric oil-core nanocarriers for nisin delivery

Nisin is an antimicrobial peptide broadly used as a preservative in the food industry. In this study, oil-core polymeric nanocapsules encapsulating nisin were prepared by a nanoprecipitation technique using three different synthetic biodegradable polymers, namely poly(butylene adipate-coterephthalate) (PBAT), Eudragit RS-100® (EUD), and poly(ε-caprolactone) (PCL), and their physical characteristics, thermal resistance and antimicrobial activity against Listeria monocytogenes were investigated. All nanocapsule formulations showed entrapment efficiency superior to 96%. EUD and PCL nanocapsules showed average diameters ranging from 145 to 303 nm, while PBAT-nisin nanocapsules showed larger size and PDI index (556.2 nm and 0.51, respectively), possibly due to changes in the organic phase equilibrium during preparation. The thermogravimetric analysis indicates lower decomposition temperatures in the PCL and EUD nanocapsules containing nisin compared with the unload nanocapsule and the contrary effect in the PBAT. Moreover, all nisin-containing polymeric nanocapsules exhibited antimicrobial activity against L. monocytogenes in both agar diffusion tests and determination of antimicrobial units (AU/mL) in liquid media. Oil-core polymeric nanocapsules have not been previously described as carriers for nisin, and the results suggested that PBAT, EUD, and PCL could be suitable polymers for nisin delivery systems

Lipid-based nanostructures for the delivery of natural antimicrobials

Encapsulation can be a suitable strategy to protect natural antimicrobial substances against some harsh conditions of processing and storage and to provide efficient formulations for antimicrobial delivery. Lipid-based nanostructures, including liposomes, solid lipid nanoparticles (SLNs), and nanostructured lipid nanocarriers (NLCs), are valuable systems for the delivery and controlled release of natural antimicrobial substances. These nanostructures have been used as carriers for bacteriocins and other antimicrobial peptides, antimicrobial enzymes, essential oils, and antimicrobial phytochemicals. Most studies are conducted with liposomes, although the potential of SLNs and NLCs as antimicrobial nanocarriers is not yet fully established. Some studies reveal that lipid-based formulations can be used for co-encapsulation of natural antimicrobials, improving their potential to control microbial pathogens

Biodegradação de penas de frango por uma bactéria queratinolítica

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Immobilization of protease extracted from Bacillus sp. P45 on different supports

Immobilization is a direct tool which not only improves the activity and stability of enzymes, but also enables their reuse. Therefore, selecting methods and supports to obtain biocatalysts with high selectivity and thermal stability is an important step. This study aimed at evaluating the immobilization of partially purified protease from Bacillus sp. P45, by different methods with the use of the following carriers: Amberlite IR® 120, montmorillonite clay, chitosan, glutaraldehyde-activated chitosan, Eupergit® C, DEAE-Cellulose® and QAE-Sephadex®. It also aimed at determining the operational stability of the derivative. The best results were obtained with the use of glutaraldehyde-activated chitosan, Amberlite IR® 120 and montmorillonite clay, with loading capacities of 25.4, 6.2 and 2.3 U/g support, respectively. Regarding the operational stability of the derivative glutaraldehyde-activated chitosan, the enzyme was found to keep 53.5% of its residual activity after being reused four times

Antibióticos comumente investigados no leite cru em laticínios sujeitos a Inspeção Estadual no Rio Grande do Sul, Brasil

Este estudo teve por objetivo identificar os antibióticos comumente investigados durante a rotina de processamento do leite cru recebido em laticínios sob Inspeção Estadual no Rio Grande do Sul (RS), entre janeiro de 2014 e fevereiro de 2015. Entre as 36 indústrias participantes, os antibióticos mais comumente investigados foram beta-lactâmicos (100%) e tetraciclinas (69%). A seleção por quais antibióticos investigar no recebimento do leite foi influenciada pela praticidade e rapidez na execução da análise (67%), em detrimento do conhecimento específico sobre quais antibióticos eram utilizados pelos produtores de leite (22%).This study aimed at identifying the commonly screened antibiotics during the dairy processing routine in raw-milk receiving points in plants inspected by the official services in the state of Rio Grande do Sul (RS), from January 2014 to February 2015. Among the 36 participating industries, the most commonly screened antibiotics were beta lactams (100%) and tetracyclines (69%). The antibiotics screened at the milk receiving point were chosen because of the practicality and speed in performing the screening (67%), rather than specific knowledge on which antibiotics the milk suppliers used. (22%)

Poultry feather hydrolysate as a protein source for growing rats

Feather protein has been considered as a protein complement for animal diets, since it is largely available as a by-product of poultry processing. In this work, a feather protein hydrolysate produced by the keratinolytic microorganism Vibrio sp. kr2 was evaluated as a feed additive. Wistar rats were fed seven experimental diets (n = 6 rats per diet) containing different protein sources: casein (CAS), soybean protein, feather hydrolysate, feather meal, and soybean protein supplemented with 10 or 20% (w/w) feather hydrolysate, and 20% feather hydrolysate supplemented methionine. Values for weight gain, feed ingest, true digestibility, feed:gain ratio, Protein Efficiency Ratio and Net Protein Ratio were similar for diets containing soybean protein and 20% feather hydrolysate supplemented methionine. Lowest values for all nutritional parameters were observed for diets containing soybean protein supplemented with 10 or 20% (w/w) feather hydrolysate, feather hydrolysate and feather meal. Protein source had a considerable influence in the final weight of liver, kidney and hearth, although no significant differences were observed for brains. These results indicate that feather hydrolysate may be useful as supplementary protein in feed formulationsA proteína da pena é uma boa fonte proteica para dietas de animais, sendo um material de grande disponibilidade como subproduto da produção avícola. Neste trabalho, um hidrolisado protéico de penas produzido pelo microrganismo queratinolítico Vibrio sp. kr2 foi avaliado como suplemento em rações. Ratos da linhagem Wistar foram alimentados com sete dietas experimentais (n = 6 ratos por dieta) contendo diferentes fontes de proteína: caseina (CAS), proteína de soja, hidrolisado de pena, farinha de pena, e proteína de soja suplementada com 10 ou 20% (w/w) hidrolisado de pena, ou 20% hidrolisado de pena suplementado com metionina. Os valores de ganho de peso, consumo, digestibilidade verdadeira, coeficiente de eficiência alimentar, coeficiente de eficiência proteica (PER) e eficiência líquida proteica (NPR) foram similares para as dietas contendo proteína de soja e proteína de soja suplementada com 20% hidrolisado de pena e metionina. Valores inferiores para todos parâmetros nutricionais foram observados para as dietas contendo 10 ou 20% hidrolisado de pena, hidrolisado de pena e fariha de pena. A fonte protéica influenciou no peso final do fígado, rins e coração, porém as diferenças não foram significativas para cérebros. Estes resultados indicam que o hidrolisado de penas pode ser usado como fonte de proteína suplementar na formulação de rações desde que suplementados com metionin