RESUMO
Carnobacterium sp., a lactic acid bacterium isolated from a maritime Antarctic lake, was evaluated for lactic acid production from a lignocellulosic hydrolysate. Eucalyptus sawdust, a residue from pulp and paper industries, was subjected to alkaline pretreatment to enhance its enzymatic hydrolysis. Fermentations were performed without and with pH control using eucalyptus enzymatic hydrolysate containing a mixture of glucose and xylose sugars. The sugars were successfully converted into lactic acid in 24â¯h, resulting in 7.6â¯g/L of lactic acid and a product yield of 0.50â¯g/g for pH controlled at 6.5. Fed-batch fermentation performed at a controlled pH of 6.5 improved both the lactic acid production (30â¯g/L) and the biomass growth (4.2â¯g/L). l-lactic acid optical purity higher than 95 % was obtained. These results demonstrated the potential usage of Carnobacterium sp in l-lactic acid production from eucalyptus.
RESUMO
Lactic acid bacteria (LAB) isolated from freshwater fish (hatcheries and captures) from Paraná river (Argentina) were analyzed by using culture-dependent approaches. The species belonging to Carnobacterium (C.) divergens, C. inhibens, C. maltaromaticum, C. viridans and Vagococcus (V.) salmoninarum were identify as predominant by RAPD-PCR and 16 s rRNA gene sequencing. C. maltaromaticum (H-17, S-30, B-42 and S-44) grew in raw fish extract and slightly reduced the medium pH (5.81-5.91). These strains exhibited moderate fish sarcoplasmic protein degradation (≤ 73 %) releasing small peptides and free amino acids, being alanine, glycine, asparagine and arginine concentrations increased in a higher extent (17.84, 1.47, 1.26 and 0.47 mg/100 mL, respectively) by S-44 strain at 96 h incubation. Interestingly C. maltaromaticum H-17 was able to inhibit Listeria monocytogenes. Results suggest that these strains would contribute to the development of new safe and healthy fishery products with improved nutritional and sensory characteristics.
RESUMO
Carnobacterium maltaromaticum C2, isolated from Brazilian smoked fish (Surubim, Pseudoplatystoma sp.), was found to exert antimicrobial activity against Listeria monocytogenes, an important foodborne pathogen. In this study, the bacteriocins produced by C. maltaromaticum C2 were purified via an extraction with XAD-16 resin, a C18 solid phase extraction, followed by reversed-phase fast protein liquid chromatography. The purified active fractions were characterized using tandem mass spectrometry, permitting the identification of multiple bacteriocins. Carnobacteriocins BM1, B1, and a variant of carnobacteriocin B2 were all found, providing much of the antilisterial activity. Additionally, we herein report the first isolation of the previously predicted antimicrobial peptide carnobacteriocin X. Moreover, C. maltaromaticum C2 produces a novel two-component lantibiotic, termed carnolysin, homologous to enterococcal cytolysin. This lantibiotic is antimicrobially inactive when tested against the non-bacteriocinogenic strain C. maltaromaticum A9b-, likely requiring an additional proteolytic cleavage to reach maturity.
Assuntos
Anti-Infecciosos/isolamento & purificação , Anti-Infecciosos/farmacologia , Peptídeos Catiônicos Antimicrobianos/farmacologia , Bacteriocinas/farmacologia , Carnobacterium/química , Listeria monocytogenes/efeitos dos fármacos , Animais , Peptídeos Catiônicos Antimicrobianos/química , Peptídeos Catiônicos Antimicrobianos/isolamento & purificação , Bacteriocinas/química , Bacteriocinas/isolamento & purificação , Brasil , Peixes/microbiologiaRESUMO
Antecedentes: En años recientes la demanda de productos alimenticios percibidos como naturales se ha incrementado de manera importante, los cuales no contienen dentro de sus ingredientes conservantes o aditivos de origen químico o artificial. Al retirar de la fórmula estos conservantes/aditivos artificiales se puede generar en el producto un medio ideal de crecimiento de bacterias alterantes o patógenas. Esto es particularmente cierto en productos cárnicos procesados empacados al vacío, donde su alta actividad acuosa, bajo pH y un largo periodo de almacenamiento a condiciones de refrigeración generan un ambiente ideal para el crecimiento de microorganismos patógenos como Listeria monocytogenes. Por tanto, esto genera la necesidad de nuevas y efectivas tecnologías que permitan su control y eliminación. Los Bio-Conservantes (adición de bacterias vivas a los productos cárnicos) ofrecen una solución ideal a este tipo de problemas directamente relacionados con la seguridad alimentaria, y a la vez satisfacen la demanda por parte de los consumidores de productos saludables. Objetivos: Determinar si el cultivo C. maltaromaticum CB1 puede controlar el crecimiento de una cepa nativa de L. monocytogenes en morcilla y chorizo empacados al vacío (película de baja permeabilidad al oxigeno). Métodos: Tres lotes diferentes de chorizo y morcilla producidos a nivel industrial fueron posteriormente inoculados con una cepa nativa de L. monocytogenes a un nivel de 102 UFC/g junto con el bio-conservante C. maltaromaticum CB1 a un nivel de 103 UFC/g. A los tratamientos denominados como control no se les aplicó el bio-conservante. Después de ser empacados al vacío, los productos fueron almacenados a dos temperaturas diferentes de 4°C (refrigeración) y 8°C (abuso de temperatura) durante 35 días. En intervalos de 7 días se hizo recuentos del crecimiento de la L. monocytogenes utilizando agar Oxford...
Assuntos
Bacteriocinas , Biotecnologia , CarnobacteriumRESUMO
Bacteriocins are ribosomally produced peptides useful for food biopreservation. An improved adsorption-desorption process is proposed for the partial purification of the bacteriocin produced by the fish isolate Carnobacterium maltaromaticum C2. Analyzis of extract by SDS-PAGE indicated this method may offer an alternative to improve the yield of purification of bacteriocins.
Assuntos
Humanos , Bacteriocinas , Fermentação , Peixes , Conservação de Alimentos , Alimentos de Origem Animal , Eletroforese , Amostras de Alimentos , Métodos , MétodosRESUMO
Bacteriocins are ribosomally produced peptides useful for food biopreservation. An improved adsorption-desorption process is proposed for the partial purification of the bacteriocin produced by the fish isolate Carnobacterium maltaromaticum C2. Analyzis of extract by SDS-PAGE indicated this method may offer an alternative to improve the yield of purification of bacteriocins.
RESUMO
Bacteriocins are ribosomally produced peptides useful for food biopreservation. An improved adsorption-desorption process is proposed for the partial purification of the bacteriocin produced by the fish isolate Carnobacterium maltaromaticum C2. Analyzis of extract by SDS-PAGE indicated this method may offer an alternative to improve the yield of purification of bacteriocins.
RESUMO
Three culture media were studied for the bacteriocin like substance (BLS) production from Carnobacterium piscicola L 103 in a batch and continuous culture system. The efficacy of the antagonistic substance against Listeria monocytogenes was tested on vacuum packaged salmon. BLS was produced in a 1.0 L bioreactor by batch and continuous culture using D-MRS, mod. D-MRS and APT as nutrient broths. Salmon fillets were inoculated with BLS (200 AU mL-1 and 800 AU mL-1) and 8.0 x 10¹ cfu cm-2 of L. monocytogenes and stored at 4ºC. The growth of L. monocytogenes was determined every 5 days during 15 days. After 12 h of batch culture the stationary growth phase of C. piscicola L 103 started, with a BLS activity of 800 AU mL-1 in D-MRS and mod. D-MRS broth, and of 400 AU mL-1 in APT broth. During continuous culture BLS activity increased to 6400 AU mL-1 in both types of MRS broths, while in APT the activity decreased to 50 AU mL-1, indicating a clear advantage of the first two culture media and also of the continuous culture system. BLS had a bacteriostatic effect on L. monocytogenes when inoculated on salmon, with counts of 6.0 x 10³ cfu cm-2 after 15 days. No significant differences were found between the two BLS activities used. In the control without BLS, L. monocytogenes counts increased to 1.0 x 10(6) cfu cm-2 after 15 days of storage.
Três meios de cultura foram avaliados quanto a produção de substâncias semelhantes a bacteriocinas (SSB) por Carnobacterium piscicola L 103, utilizando um sistema contínuo de cultura. A eficácia da substância antagonista contra Listeria monocytogenes foi testada em salmão embalado a vácuo. As SSB foram produzidas em bioreator de 1.0 L, em cultura contínua e em cultura estacionária, utilizando D-MRS, mod. D-MRS e APT como meios de cultivo. Filés de salmão foram inoculados com SSB (200 AU mL-1 e 800 AU mL-1) e L. monocytogenes (8.0 x 10¹ ufc cm-2) e mantidos a 4ºC. O crescimento de L. monocytogenes foi verificado a cada 5 dias, durante 15 dias. C. piscicola L 103 antigiu a fase estacionária depois de 12 h de incubação em cultivo em batelada, sendo a atividade SSB de 800 AU mL-1 nos meios D-MRS e mod. D-MRS e de 400 AU mL-1 no caldo APT. Durante a cultura continua, a atividade SSB aumentou até 6400 AU mL-1 nos dois tipos de caldo MRS, ao passo que no caldo APT esta atividade diminuiu a 50 AU mL-1, indicando uma clara vantagem de uso dos dois primeiros meios de cultura e do sistema de crescimento contínuo. SSB mostrou efeito bacteriostático sobre L. monocytogenes quando inoculada em salmão, com contagens de 6,0 x 10³ ufc cm-2 após 15 dias. Não foram encontradas diferenças significantes entre as duas atividades utilizadas. No ensaio controle, sem SSB, a contagem de L. monocytogenes aumentou até 1,0 x 10(6) ufc cm-2 após 15 dias de estocagem.