Application of crude xylanase from Bacillus licheniformis 77-2 to the bleaching of eucalyptus Kraft pulp

Alkalophilic Bacillus licheniformis 77-2 produced an extracellular alkali-tolerant xylanase with negligible cellulase activity in medium containing corn straw. The effectiveness of crude xylanase on treatment of eucalyptus Kraft pulp was evaluated. A biobleaching experiment was carried out to compare the chlorine saving with pulp treated and untreated by the enzyme. Two-stage bleaching was employed, using a ClO2 chlorination and NaOH extraction (DE sequence). With the enzymatic treatment, in order to obtain the same value of Kappa number and brightness, respectively 28.5 and 30% less ClO2 was required in comparison to the enzymatically untreated samples.

Optimization of xylanase production by Bacillus circulans D1 in submerged fermentation using response surface methodology

In this work, a 3(3) factorial design was performed with the aim of optimizing the culture conditions for xylanase production by an alkalophilic thermophilic strain of Bacillus circulans, using response surface methodology. The variables involved in this study were xylan concentration (X-1), pH (X-2) and cultivation time (X-3). The optimal response region was approached without using paths of steepest ascent. Statistical analysis of results showed that, in the range studied, only pH did not have a significant effect on xylanase production. A second-order model was proposed to represent the enzymic activity as a function of xylan concentration (X-1) and cultivation time (X-3). The optimum xylan concentration and cultivation time were 5 g/l and 48 h, respectively. Under these conditions, the model predicted a xylanase activity of 19.1 U/ml. (C) 2002 Elsevier B.V. Ltd. All rights reserved.

Production of cyclodextrins by CGTase from Bacillus clausii using different starches as substrates

Cyclodextrins ( CDs) are cyclic oligasaccharides composed by D- glucose monomers joined by alpha- 1,4-D glicosidic linkages. The main types of CDs are alpha-,beta-and gamma-CDs consisting of cycles of six, seven, and eight glucose monomers, respectively. Their ability to form inclusion complexes is the most important characteristic, allowing their wide industrial application. The physical property of the CD-complexed compound can be altered to improve stability, volatility, solubility, or bio-availability. The cyclomaltodextrin glucanotransferase ( CGTase, EC 2.4.1.19) is an enzyme capable of converting starch into CD molecules. In this work, the CGTase produced by Bacillus clausii strain E16 was used to produce CD from maltodextrin and different starches ( commercial soluble starch, corn, cassava, sweet potato, and waxy corn starches) as substrates. It was observed that the substrate sources influence the kind of CD obtained and that this CGTase displays a beta- CGTase action, presenting a better conversion of soluble starch at 1.0%, of which 80% was converted in CDs. The ratio of total CD produced was 0: 0.89: 0.11 for alpha/beta/gamma. It was also observed that root and tuber starches were more accessible to CGTase action than seed starch under the studied conditions.

Evaluation of efficacy of preservatives associated with Achillea millefolium L. extract against Bacillus subtilis

A eficácia antimicrobiana de conservantes empregados em formulações cosméticas foi avaliada usando Phenova® e Imidazolinidil uréia que inibiram o crescimento de Bacillus subtilis no extrato de Achillea millefolium L. e Nipagin®/ Nipasol® 0,2% em propilenoglicol não apresentaram efeito microbicida.

Controle biológico da podridão radicular (Pythium aphanidermatum) e promoção de crescimento por Pseudomonas chlororaphis 63-28 e Bacillus subtilis GB03 em alface hidropônica

Podridões radiculares causadas por espécies de Pythium são um importante problema em cultivos hidropônicos. Sintomas de subdesenvolvimento são observados nas plantas parasitadas pelo patógeno, sendo muitas vezes não diagnosticados pelo produtor. O objetivo do trabalho foi avaliar o controle biológico da podridão radicular causada por Pythium aphanidermatum e a promoção de crescimento por Pseudomonas chlororaphis 63-28 e Bacillus subtilis GB03, reconhecidos agentes de controle biológico de doenças de plantas. A inoculação das plantas com P. aphanidermatum ocasionou o subdesenvolvimento, sendo essa diminuição de 20%. A adição dos agentes de biocontrole na solução nutritiva teve um efeito positivo no aumento da massa (6% a 13%), no número de folhas (4% a 7%) e no teor de clorofila (3%) das plantas de alface. Entretanto, maiores estudos devem ser realizados para melhorar a capacidade de controle da doença e de promoção de crescimento pelos agentes de biocontrole estudados no cultivo de alface hidropônica.

Microrganismos heterotróficos mesófilos e bactérias do grupo do Bacillus cereus em leite integral submetido a ultra alta temperatura

Cento e dez amostras de 11 diferentes marcas de leite ultra alta temperatura (UAT), comercializadas em São José do Rio Preto - SP, foram submetidas à contagem de microrganismos heterotróficos mesófilos viáveis e à pesquisa de bactérias do grupo do Bacillus cereus. A população de microrganismos mesófilos variou de <1,0´10² UFC/ml a >1,0´10(6) UFC/ml. Bactérias do grupo do Bacillus cereus foram verificadas em 13 (11,8%) amostras. Os resultados evidenciaram elevada população de microrganismos indicadores mesófilos.

INFLUÊNCIA DE BACILLUS SUBTILIS NA ECLOSÃO, ORIENTAÇÃO E INFECÇÃO DE HETERODERA GLYCINES em SOJA

A utilização de microrganismos para fins de controle biológico de doenças em plantas tem sido muito estudada no mundo. No caso do nematóide de cisto da soja (Heterodera glycines), uma das principais doenças da soja, o controle biológico é de grande importância devido à ausência de controle químico eficiente. Para se estudar o efeito de Bacilllus subtilis sobre H. glycines, foram conduzidos alguns experimentos de casa de vegetação e laboratório. Nos trabalhos de laboratório, verificou-se, em câmara de eclosão, que a presença de B. subtilis reduz a eclosão de ovos de H. glycines estimulados com exsudatos de sementes de soja. Foi observado também que o tratamento de raiz de soja com a bactéria inibiu a migração de larvas juvenis de H. glycines para a planta em comparação à raiz não tratada com a bactéria. Nos ensaios de casa de vegetação, utilizando-se vasos com solo infestados com ovos de H. glycines, observou-se uma redução de fêmeas na raiz de soja quando o solo ou sementes foram tratadas previamente com formulação pó-molhável ou calda contendo B. subtilis, respectivamente. Com base nesses resultados e sabendo-se que H. glycines apresenta dependência de estímulo de exsudatos vegetais para eclosão e orientação das larvas, pode-se afirmar que B. subtilis interfere nesse estímulo prejudicando o desenvolvimento do ciclo do nematóide.

TRATAMENTO DE SEMENTES DE ARROZ, TRIGO, FEIJÃO E SOJA COM UM PRODUTO FORMULADO À BASE DE CÉLULAS E DE METABÓLITOS DE Bacillus subtilis

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Effect of Bacillus of Calmette-Guérin, Avridine and Propionlbacterium acnes as immunomodulators on rabies in mice

Avaliou-se a resposta imune celular e humoral de camundongos inoculados com vírus rábico de rua e submetidos aos imunomoduladores Onco-BCG, avridina e Propionibacterium acnes. Os animais submetidos ao tratamento com P.acnes apresentaram um maior percentual de sobrevivência quando comparados aos dos demais tratamentos. Foram observados menores níveis de IFN-g nos animais infectados, sugerindo imunossupressão viral. O teste do Coxim Plantar não foi eficaz para a detecção da resposta de hipersensibilidade retardada na metodologia utilizada, contrariamente ao MIF. A sobrevivência dos animais não apresentou correlação com os níveis de anticorpos soroneutralizantes, concentração de IFN-g e resposta ao MIF.

Pectinolytic enzyme production by Bacillus species and their potential application on juice extraction

Five Bacillus strains isolated from decaying vegetable material were cultivated on wheat bran and endo-polygalacturonases, exo-polygalacturonase and pectin lyase activities in the crude enzymatic solution obtained were determined. Highest activity was observed for all enzymes when fermentation was carried out at 28 degreesC, the highest activity values were obtained after 120 h of cultivation for exo-PG and after 48 h for endo-PG and PL. The use of the enzymatic solution for treatment of fruits and vegetable mash afforded a high juice extraction and a pulp with good pressing characteristics.

Ability of bacteriophages isolated from different sources to reduce Salmonella enterica serovar enteritidis in vitro and in vivo

Salmonella enterica serovar Enteritidis-lysing bacteriophages isolated from poultry or human sewage sources were used to reduce Salmonella Enteritidis in vitro and in experimentally infected chicks. Cocktails of 4 different bacteriophages obtained from commercial broiler houses (CB4O) and 45 bacteriophages from a municipal wastewater treatment plant (WT45O) were evaluated. In experiment 1, an in vitro crop assay was conducted with selected bacteriophage concentrations (105 to 101 pfu/mL) to determine ability to reduce Salmonella Enteritidis in the simulated crop environment. Following 2 h at 37 degrees C, CB40 or WT45O reduced Salmonella Enteritidis recovery by 1.5 or 5 log, respectively, as compared with control. However, CB40 did not affect total SE recovery after 6 h, whereas WT45O resulted in up to a 6-log reduction of Salmonella Enteritidis. In experiment 2, day-of-hatch chicks were challenged orally with 3 x 103 cfu /chick Salmonella Enteritidis and treated cloacally with 1 X 109 WT45O pfu/chick I h postchallenge. One hour later, chicks were treated or not with a commercially available probiotic (Floramax-B11). Both treatments significantly reduced Salmonella Enteritidis recovery from cecal tonsils at 24 h following vent lip application as compared with controls, but no additive effect was observed with the combination of bacteriophages and probiotic. In experiment 3, day-of-hatch chicks were challenged orally with 9 x 103 cfu/chick Salmonella Enteritidis and treated via oral gavage with I X 108 CB40 pfu/chick, 1.2 x 108 WT45O pfu/chick, or a combination of both, I h postchallenge. All treatments significantly reduced Salmonella Enteritidis recovered from cecal tonsils at 24 h as compared with untreated controls, but no significant differences were observed at 48 h following treatment. These data suggest that some bacteriophages can be efficacious in reducing SE colonization in poultry during a short period, but with the bacteriophages and methods presently tested, persistent reductions were not observed.

Evaluation of macrophage activity and antibody production in genetically selected mice infected with Leptospira serovar pomona

The aim of the present study was to evaluate the role of macrophage activity and antibody production in experimental infection with Leptospira Pomona in mice genetically selected for high (H) or low (L) humoral immune response. To evaluate macrophage activity, reactive oxygen and nitrogen intermediates were determined. Also, the production of tumor necrosis factor (TNF-alpha) and the recovery of Leptospira-specific antibodies in the kidneys and liver were assessed; histological lesions were analyzed using the hematoxylin-eosin technique, and Leptospira antigens in tissues were determined by immunohistochemistry. Results showed that recovery of microorganisms from the analyzed organs was lower in LIV-A mice. However, HIV-A animals showed total restraint since the 14th day after infection, whereas LIV-A mice still had bacteria in the liver at the 21st post-infection day. Immune response against Pomona serovar in those lineages was characterized as high production of antibodies, mainly in late periods of the infectious process. The production of reactive oxygen and nitrogen intermediates also contributed to the elimination of Leptospira Pomona in all two lineages; H2O2 production was an important factor in HIV-A mice, as well as NO production in the LIV-A animals, mainly at the latest post-inoculation periods. The same occurred regarding TNF-alpha production. Severe renal lesions were observed at periods in which larger numbers of leptospires were isolated using the culture technique. Tissue alterations persisted in LIV-A mice, even at periods in which leptospires were not recovered. Immunohistochemistry showed to be more sensitive than culturing. However, both techniques were appropriate for the agent identification in the studied lineages. Results suggest that such lineages could represent an important model to investigate pathogenesis and immune response against the varied serovars of leptospires.

Xylanase production by Bacillus circulans D1 using maltose as carbon source

Bacillus circulans D1 is a good producer of extracellular thermostable xylanase. Xylanase production in different carbon sources was evaluated and the enzyme synthesis was induced by various carbon sources. It was found that D-maltose is the best inducer of the enzyme synthesis ( 7.05 U/ mg dry biomass at 48 h), while D-glucose and D-arabinose lead to the production of basal levels of xylanase. The crude enzyme solution is free of cellulases, even when the microorganism was cultivated in a medium with D-cellobiose. When oat spelt xylan was supplemented with D-glucose, the repressive effect of this sugar on xylanase production was observed at 24 h, only when used at 5.0 g/ L, leading to a reduction of 60% on the enzyme production. on the other hand, when the xylan medium was supplemented with D- xylose ( 3.0 or 5.0 g/ L), this effect was more evident ( 80 and 90% of reduction on the enzyme production, respectively). Unlike that observed in the xylan medium, glucose repressed xylanase production in the maltose medium, leading to a reduction of 55% on the enzyme production at 24 h of cultivation. Xylose, at 1.0 g/ L, induced xylanase production on the maltose medium. on this medium, the repressive effect of xylose, at 3.0 or 5.0 g/ L, was less expressive when compared to its effect on the xylan medium.