BackgroundThere is an imperative necessity for alternative sources of energy able to reduce the world dependence of fossil oil. One of the most successful options is ethanol obtained mainly from sugarcane and corn fermentation. The foremost residue from sugarcane industry is the bagasse, a rich lignocellulosic raw material uses for the production of ethanol second generation (2G). New cellulolytic and hemicellulytic enzymes are needed, in order to optimize the degradation of bagasse and production of ethanol 2G.ResultsThe ability to produce hemicellulases and related enzymes, suitable for lignocellulosic biomass deconstruction, was explored using 110 endophytic fungi and 9 fungi isolated from spoiled books in Brazil. Two initial selections were performed, one employing the esculin gel diffusion assay, and the other by culturing on agar plate media with beechwood xylan and liquor from the hydrothermal pretreatment of sugar cane bagasse. A total of 56 isolates were then grown at 29°C on steam-exploded delignified sugar cane bagasse (DEB) plus soybean bran (SB) (3:1), with measurement of the xylanase, pectinase, β-glucosidase, CMCase, and FPase activities. Twelve strains were selected, and their enzyme extracts were assessed using different substrates. Finally, the best six strains were grown under xylan and pectin, and several glycohydrolases activities were also assessed. These strains were identified morphologically and by sequencing the internal transcribed spacer (ITS) regions and the partial β-tubulin gene (BT2). The best six strains were identified as Aspergillus niger DR02, Trichoderma atroviride DR17 and DR19, Alternaria sp. DR45, Annulohypoxylon stigyum DR47 and Talaromyces wortmannii DR49. These strains produced glycohydrolases with different profiles, and production was highly influenced by the carbon sources in the media.ConclusionsThe selected endophytic fungi Aspergillus niger DR02, Trichoderma atroviride DR17 and DR19, Alternaria sp. DR45, Annulohypoxylon stigyum DR47 and Talaromyces wortmannii DR49 are excellent producers of hydrolytic enzymes to be used as part of blends to decompose sugarcane biomass at industrial level.
Ethanol can be produced from cellulosic biomass in a process known as simultaneous saccharification and fermentation (SSF). The presence of yeast together with the cellulolytic enzyme complex reduces the accumulation of sugars within the reactor, increasing the ethanol yield and saccharification rate. This paper reports the isolation of Saccharomyces cerevisiae LBM-1, a strain capable of growth at 42 °C. In addition, S. cerevisiae LBM-1 and Kluyveromyces marxianus UFV-3 were able to ferment sugar cane bagasse in SSF processes at 37 and 42 °C. Higher ethanol yields were observed when fermentation was initiated after presaccharification at 50°C than at 37 or 42° C. Furthermore, the volumetric productivity of fermentation increased with presaccharification time, from 0.43 g/L/h at 0 h to 1.79 g/L/h after 72 h of presaccharification. The results suggest that the use of thermotolerant yeasts and a presaccharification stage are key to increasing yields in this process.
RESUMO -Objetivou-se verificar o efeito de três épocas de semeadura -outubro (antecipada), novembro (normal) e dezembro (tardia) -sobre as características fenológicas, produtivas e qualitativas de quatro híbridos de girassol: Rumbosol-91 (forrageiro), M-734 (duplo propósito), C-11 (duplo propósito) e BRS-191 (granífero) destinados à produção de silagem. O delineamento experimental foi em blocos ao acaso, com arranjo fatorial 4 x 3 (quatro híbridos x três épocas de semeadura) e quatro repetições. A semeadura em outubro resultou em ciclo mais longo, altura de planta mais elevada e diâmetro e participação de capítulo menores, como conseqüência da temperatura, da insolação e do fotoperíodo, que foram mais baixos nessa época. Os híbridos Rumbosol-91 e BRS-191 semeados em novembro apresentaram taxas de acamamento mais quebramento maiores, de 49,6 e 65,7%, respectivamente. Os híbridos BRS-191 e M-734 semeados em dezembro apresentaram produtividades de fitomassa maiores, com 39,71 e 43,76 t ha -1 de matéria verde e 11,31 e 11,41 t ha -1 de matéria seca, respectivamente. Nos constituintes da planta, os teores de PB aumentaram e os de FDN, FDA e LDA diminuíram, respectivamente, para colmo, folhas e capítulo. Na planta inteira, os teores de MS oscilaram de 23,2%, para o híbrido Rumbosol-91 semeado em novembro, a 47,9%, para o híbrido C-11 semeado em dezembro, indicando que os híbridos possuem capacidade diferenciada de retenção de umidade em estádio de maturidade fisiológica semelhante da cultura (fase R-9). Os teores de PB variaram de 7,0 a 15,7%, demonstrando a riqueza protéica da cultura. Os teores de LDA da planta inteira oscilaram de 6,5 a 12,4%, sendo que os híbridos M-734 semeado em dezembro e C-11 semeado em outubro apresentaram os teores mais baixos. Visando à produção de silagem de elevada qualidade, o híbrido M-734 semeado em dezembro apresentou melhor relação entre fenologia, produtividade e composição bromatológica.Palavras-chave: capítulo, características agronômicas, Helianthus annuus, rendimento de fitomassa Sowing dates effects on the phenology, yield and qualitative traits of sunflower hybrids for silage making ABSTRACT -The objective of this study was to estimate the effect of three sowing dates: October (early), November (normal) and December (late), on the phenological, yield and qualitative traits of four sunflower hybrids: Rumbosol-91 (forage), M-734 (double purpose), C-11 (double purpose) and BRS-191 (grain) grown for silage making. A 4 x 3 factorial treatment combination (four hybrids x three sowing dates) was allocated in a randomized block design with four replications. The October sowing brought about longer cycle, higher plant height, and smaller seed head diameter and contribution due to the prevailing climatic conditions of lower temperature, insolation and photoperiod during the crop growth period. The Rumbosol-91 and BRS-191 hybrids sowed in November showed higher lodging plus stalk breaking proportion of about 49.6 and 65.7%, respectively. The BRS-191 and M-734 hybrids sowed in December sh...
2015): Xylanase production by endophytic Aspergillus niger using pentose-rich hydrothermal liquor from sugarcane bagasse, Biocatalysis and Biotransformation, AbstractFungal xylanases have been widely studied and various production methods have been proposed using submerged and solid-state fermentation. this class of enzyme is used to supplement cellulolytic enzyme cocktails in order to enhance the enzymatic hydrolysis of plant cell walls. the present work investigates the production of xylanase and other accessory enzymes by a recently isolated endophytic Aspergillus niger DR02 strain, using the pentose-rich liquor from hydrothermal pretreatment of sugarcane bagasse as carbon source. batch and fed-batch submerged cultivation approaches were developed in order to minimize the toxicity of the liquor and increase enzyme production. maximum xylanase activities obtained were 458.1 u/ml for constant fed-batch, 428.1 u/ml for exponential fed-batch, and 264.37 u/ml for pulsed fed-batch modes. the results indicated that carbon-limited fed-batch cultivation can reduce fungal catabolite repression, as well as overcome possible negative effects of toxic compounds present in the pentose-rich liquor. enzymatic panel and mass spectrometric analyses of the fed-batch A. niger secretome showed high levels of xylanolytic enzymes (gh10, gh11, and gh62 cazy families), together with cellobiohydrolase (g6 and gh7), b-glucosidase, b-xylosidase (gh3), and feruloyl esterase (ce1) accessory enzyme activities. the yields of glucose and xylose from enzymatic hydrolysis of hydrothermally pretreated sugarcane bagasse increased by 43.7 and 65.3%, respectively, when a commercial cellulase preparation was supplemented with the A. niger DR02 constant fed-batch enzyme complex.Keywords: aspergillus niger DR02, xylanase, accessory enzymes, pentose-rich liquor, hydrothermal pretreatment correspondence: José geraldo da cruz Pradella, brazilian laboratory of science and technology of bioethanol -ctbe, Rua giuseppe maximo scolfaro 10000, Pólo ii de alta Biocatalysis and Biotransformation, 2015; early online: 1-13 issn 1024-2422 print/issn 1029-2446 online © 2015 informa uK, ltd.
RESUMOEste trabalho teve por objetivo avaliar o efeito dos sistemas de ordenha e de resfriamento na contagem bacteriana total (CBT) e na quantidade de leite com CBT ≤ 10 5 , que representa leite de alta qualidade. Um total de 12.221 registros de CBT do leite foi obtido de uma indústria láctea da região Oeste do Paraná, no período de janeiro a outubro de 2006. Após as coletas, a qualidade do leite foi analisada em laboratório pelo método de citometria de fluxo. Os dados de CBT foram classificados por sistema de ordenha, tipo de resfriador e intervalos da CBT, segundo critério da Instrução Normativa 62, e submetidos à análise de independência de Qui-Quadrado. As proporções de CBT do leite entre tipos de resfriadores, em cada sistema de ordenha, foram comparadas utilizando-se a estatística calculada Z. Observou-se menor (p < 0,01) valor de CBT do leite de vacas submetidas à ordenha canalizada e do leite resfriado a granel. A proporção das amostras de leite avaliadas nos três níveis de CBT resfriadas por sistema de imersão não diferiu (p = 0,1549) do leite resfriado a granel, quando o leite foi obtido de rebanhos ordenhados por ordenha canalizada. A alta qualidade microbiológica do leite da região Oeste do Paraná é obtida quando os produtores utilizam em suas propriedades rurais a ordenha canalizada e o sistema de resfriamento a granel. PALAVRAS-CHAVE: Higienização, ordenhadeira, qualidade microbiológica, resfriador. ABSTRACT TOTAL BACTERIAL COUNT OF MILK IN DIFFERENT SYSTEMS OF MILKING ANDCOOLING. This study aimed to evaluate the effect of milking systems and cooling on total bacterial count (TBC), and the amount of milk samples with TBC ≤ 10 5 , which represents high-quality milk. A total of 12,221 records of milk TBC were obtained from a dairy industry in the western region of Paraná State, Brazil, from January to October 2006. After the sampling was conducted, the milk quality was analyzed in the laboratory by the method of flow cytometry. The TBC data were classified by milking system, type of coolers and intervals of the TBC, in accordance with Normative Instruction 62, and submitted to the chi-square test for independence. The proportions of milk TBC among types of coolers at each milking system were compared using the calculated statistic Z. A lower TBC value (p < 0.01) was observed in milk obtained from cows milked using a piped system and from bulk cooled milk. The proportion of milk samples evaluated at three levels of TBC cooled by the immersion system did not differ (p = 0.1549) from bulk cooled milk when the milk was obtained from herds milked with a piped system. The best microbiological quality of milk in the western region of Paraná was achieved with a piped milking system and bulk cooling.KEY WORDS: Cleaning, cooler, microbiological quality, milking. INTRODUÇÃOO parâmetro utilizado com maior frequência para avaliar a qualidade do leite é a contagem bacteriana total (CBT) (Bava et al., 2009). O valor da CBT acima dos limites tolerados pela legislação é indicativo de deficiência na limpeza e higieniz...
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