8 research outputs found

    Production of ethanol from mesquite [Prosopis juliflora (SW) D.C.] pods mash by Zymomonas mobilis in submerged fermentation

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    Mesquite [Prosopis juliflora (SW) D.C.], a perennial tropical plant commonly found in Brazilian semi-arid region, is a viable raw material for fermentative processes because of its low cost and production of pods with high content of hydrolysable sugars which generate many compounds, including ethanol. This study aimed to evaluate the use of mesquite pods as substrate for ethanol production by Z. mobilis UFPEDA205 in a submerged fermentation. The fermentation was assessed for rate of substrate yield to ethanol, rate of ethanol production and efficiency of fermentation. The very close theoretical (170 g L-1) and experimental (165 g L-1) maximum ethanol yields were achieved at 36 h of fermentation. The highest counts of Z. mobilis UFEPEDA-205 (both close to 6 Log cfu mL-1) were also noted at 36 h. Highest rates of substrate yield to ethanol (0.44 g ethanol g glucose-1), of ethanol production (4.69 g L-1 h-1) and of efficiency of fermentation (86.81%) were found after 30 h. These findings suggest mesquite pods as an interesting substrate for ethanol production using submerged fermentation by Z. mobilis.A algaroba [Prosopis juliflora (SW) D.C.] é uma planta tropical perene comumente encontrada no semi-árido brasileiro e apresenta-se como matéria-prima viável para o processo fermentativo por possuir baixo custo e para produzir vagens que contém um elevado teor de açúcares hidrolisáveis, os quais podem gerar diversos compostos, incluindo etanol. Avaliou-se o uso de vagens de algaroba como substrato para produção de etanol por Z. mobilis UFPEDA-205 por meio de fermentação submersa. O processo fermentativo foi avaliado por meio da mensuração da taxa de conversão de substrato em etanol, taxa de produção de etanol e eficiência de fermentação. Os valores muito próximos encontrados para o fornecimento máximo teórico (170 g L-1) e experimental (165 g L-1) de etanol foram alcançados após 36 h de fermentação. O valor de contagem experimental de Z. mobilis UFEPEDA-205 (próximo a 6 Log cfu mL-1) foi encontrado após 36 h de fermentação. As mais elevadas taxas de conversão de substrato para etanol (0,44 g ethanol g glucose-1), de produção de etanol (4,69 g L-1 h-1) e de eficiência de fermentação (86,81%) foram encontrados depois de 30 h. Conclui-se que as vagens de algaroba apresentam potencial como substrato emergente para produção de etanol por Z. mobilis por meio de fermentação submersa

    Production of ethanol from mesquite ( Prosopis juliflora (SW) D.C.) pods mash by Zymomonas mobilis and Saccharomyces cerevisiae

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    This study aimed to assess the use of mesquite pods hydrated mash as biomass for the growth of Saccharomyces cerevisiae UFEPEDA-1012 and Zymomonas mobilis UFEPEDA-205 and for ethanol production using a submerged fermentation. A 23 factorial design was used to analyze the effects of the type of microorganism, time of fermentation and condition of cultivation on the ethanol production in mesquite pods mash (30 g 100 mL-1). From the obtained results the hydrated mesquite pods mash presented as a good substrate for the growth of S. cerevisiae and Z. mobilis in comparison to the standard media. The effect that most affected the ethanol production was the type of microorganism. The highest ethanol concentration (141.1 gL-1) was found when Z. mobilis was cultivated in mesquite pods mash under static condition for 36 hrs. Ethanol production by S. cerevisiae was higher (44.32 gL-1) after 18 hrs of fermentation under static condition. According to these results, the mesquite pods could be known as an alternative substrate to be used for biotechnological purposes, mainly for ethanol production

    Vídeos educativos para o ensino de química: apontamentos sobre o Telecurso 2000

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    The audiovisual language can be characterized by mobilizing senses and perceptions in people, and it is recognized as an important tool in the educational process. In Brazil, Telecurso 2000 played an important role in the dissemination of videos as a teaching tool. Taking into consideration the historical importance, in this work were analyzed 50 chemistry videos from Telecurso 2000, with emphasis in the experiments, animations, nature of science and conceptual problems. Firstly, each video was watched in order to identify the aspects for the analysis. After that, the videos were analyzed with focus on the categories.  The presence of experiments is remarkable, as by number (78) as by way that had privileged an investigative perspective. Animations are mostly presented together to experiments and can be relevant for the learning of abstract concepts, although to be commonly simple. Science visions, in some moments, denote an emphasis in observation, but it was also observed a human participation in the science construction. The most of conceptual problems was concerned to non actualization or excessive language simplifications. Three conceptual problems can be considered as chemistry mistakes. The low chemical symbols explorations require attention. In general, the results pointed out the potentiality of those videos, especially for the diffusion of chemistry science.El lenguaje audiovisual se caracteriza por movilizar diversos sentidos y percepciones en los espectadores, teniendo su uso reconocido en el proceso educativo. En Brasil, el Telecurso 2000 desempeñó un importante papel en la difusión de los videos como herramienta de enseñanza. Teniendo en cuenta su importancia histórica, este estudio analizó lecciones de química de 50 vídeos del Telecurso 2000 con especial atención a los experimentos, animaciones, visión de ciencia y problemas conceptuales. Los vídeos fueron integralmente asistidos para el registro de los pasajes de cada categoría y posteriormente asistidos nuevamente para el análisis. La presencia de experimentos fue un aspecto notable tanto por la cantidad (78 en total) cuanto enfoque que consideró una perspectiva de investigación. Las animaciones, que en general, son presentadas conjuntamente a los experimentos, pueden ayudar la construcción de conceptos abstractos, a pesar de su simplicidad. Desde el punto de vista de visión de ciencia, a veces se verifica énfasis en la observación, pero también se observa el carácter humano en esta construcción. En relación con los problemas conceptuales, la mayoría se refiere a desactualizaciones de las terminologías o simplificación de la lengua, siendo notado tres casos de errores científicos. El bajo nivel de exploración de la simbología química es un factor que debe considerarse. En general, los resultados indican el potencial del material, especialmente para la difusión de la ciencia química.A linguagem audiovisual caracteriza-se por mobilizar diversos sentidos e percepções nos sujeitos expectadores, tendo seu uso reconhecido no processo educativo. No Brasil, o Telecurso 2000 desempenhou importante papel na difusão dos vídeos como ferramenta de ensino. Considerando sua importância histórica, neste trabalho foram analisadas as 50 vídeo-aulas de química do Telecurso 2000, com especial atenção para a abordagem experimental, animações, visão de ciência e problemas conceituais. Os vídeos foram integralmente assistidos para registro das passagens das categorias estabelecidas, sendo assistidos novamente para análise. A presença de experimentos é marcante, tanto pela quantidade (78 no total), quanto pela abordagem que considerou na maioria dos casos uma perspectiva investigativa. As animações, em geral conjunta aos experimentos, podem se mostrar um auxílio para a construção de conceitos abstratos, apesar de sua simplicidade. A visão de ciência denota uma ênfase demasiada na observação, mas também se observa o caráter humano nessa construção. Em relação aos problemas conceituais, a maioria se refere a desatualizações de terminologias ou excessivas simplificações da linguagem, sendo encontrados três casos de conceitos equivocados cientificamente. A pouca exploração da simbologia química é um fator que necessita de atenção. De forma geral, os resultados apontam potencialidades do material, sobretudo tendo em vista a difusão da ciência química por meio do audiovisual

    Production of ethanol from mesquite ( Prosopis juliflora (SW) D.C.) pods mash by Zymomonas mobilis and Saccharomyces cerevisiae

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    This study aimed to assess the use of mesquite pods hydrated mash as biomass for the growth of Saccharomyces cerevisiae UFEPEDA-1012 and Zymomonas mobilis UFEPEDA-205 and for ethanol production using a submerged fermentation. A 23 factorial design was used to analyze the effects of the type of microorganism, time of fermentation and condition of cultivation on the ethanol production in mesquite pods mash (30 g 100 mL-1). From the obtained results the hydrated mesquite pods mash presented as a good substrate for the growth of S. cerevisiae and Z. mobilis in comparison to the standard media. The effect that most affected the ethanol production was the type of microorganism. The highest ethanol concentration (141.1 gL-1) was found when Z. mobilis was cultivated in mesquite pods mash under static condition for 36 hrs. Ethanol production by S. cerevisiae was higher (44.32 gL-1) after 18 hrs of fermentation under static condition. According to these results, the mesquite pods could be known as an alternative substrate to be used for biotechnological purposes, mainly for ethanol production

    Hygienic-sanitary working practices and implementation of a Hazard Analysis and Critical Control Point (HACCP) plan in lobster processing industries

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    This study aimed to verify the hygienic-sanitary working practices and to create and implement a Hazard Analysis Critical Control Point (HACCP) in two lobster processing industries in Pernambuco State, Brazil. The industries studied process frozen whole lobsters, frozen whole cooked lobsters, and frozen lobster tails for exportation. The application of the hygienic-sanitary checklist in the industries analyzed achieved conformity rates over 96% to the aspects evaluated. The use of the Hazard Analysis Critical Control Point (HACCP) plan resulted in the detection of two critical control points (CCPs) including the receiving and classification steps in the processing of frozen lobster and frozen lobster tails, and an additional critical control point (CCP) was detected during the cooking step of processing of the whole frozen cooked lobster. The proper implementation of the Hazard Analysis Critical Control Point (HACCP) plan in the lobster processing industries studied proved to be the safest and most cost-effective method to monitor each critical control point (CCP) hazards
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