Trichoderma harzianum MTCC 5179 impacts the population and functional dynamics of microbial community in the rhizosphere of black pepper (Piper nigrum L )

Abstract Employing Illumina Hiseq whole genome metagenome sequencing approach, we studied the impact of Trichoderma harzianum on altering the microbial community and its functional dynamics in the rhizhosphere soil of black pepper (Piper nigrum L.). The metagenomic datasets from the rhizosphere with (treatment) and without (control) T. harzianum inoculation were annotated using dual approach, i.e., stand alone and MG-RAST. The probiotic application of T. harzianum in the rhizhosphere soil of black pepper impacted the population dynamics of rhizosphere bacteria, archae, eukaryote as reflected through the selective recruitment of bacteria [Acidobacteriaceae bacterium (p = 1.24e-12), Candidatus koribacter versatilis (p = 2.66e-10)] and fungi [(Fusarium oxysporum (p = 0.013), Talaromyces stipitatus (p = 0.219) and Pestalotiopsis fici (p = 0.443)] in terms of abundance in population and bacterial chemotaxis (p = 0.012), iron metabolism (p = 2.97e-5) with the reduction in abundance for pathogenicity islands (p = 7.30e-3), phages and prophages (p = 7.30e-3) with regard to functional abundance. Interestingly, it was found that the enriched functional metagenomic signatures on phytoremediation such as benzoate transport and degradation (p = 2.34e-4), and degradation of heterocyclic aromatic compounds (p = 3.59e-13) in the treatment influenced the rhizosphere micro ecosystem favoring growth and health of pepper plant. The population dynamics and functional richness of rhizosphere ecosystem in black pepper influenced by the treatment with T. harzianum provides the ecological importance of T. harzianum in the cultivation of black pepper.

Screening of Trichoderma isolates for their potential of biosorption of nickel and cadmium

Abstract Fourteen Trichoderma isolates were evaluated for their tolerance to two heavy metals, nickel and cadmium. Three isolates, MT-4, UBT-18, and IBT-I, showed high levels of nickel tolerance, whereas MT-4, UBT-18, and IBT-II showed better tolerance of cadmium than the other isolates. Under nickel stress, biomass production increased up to a Ni concentration of 60 ppm in all strains but then decreased as the concentrations of nickel were further increased. Among the nickel-tolerant isolates, UBT-18 produced significantly higher biomass upon exposure to nickel (up to 150 ppm); however, the minimum concentration of nickel required to inhibit 50% of growth (MIC50) was highest in IBT-I. Among the cadmium-tolerant isolates, IBT-II showed both maximum biomass production and a maximum MIC50 value in cadmium stress. As the biomass of the Trichoderma isolates increased, a higher percentage of nickel removal was observed up to a concentration of 40 ppm, followed by an increase in residual nickel and a decrease in biomass production at higher nickel concentrations in the medium. The increase in cadmium concentrations resulted in a decrease in biomass production and positively correlated with an increase in residual cadmium in the culture broth. Nickel and cadmium stress also influenced the sensitivity of the Trichoderma isolates to soil fungistasis. Isolates IBT-I and UBT-18 were most tolerant to fungistasis under nickel and cadmium stress, respectively.

The improvement of competitive saprophytic capabilities of Trichoderma species through the use of chemical mutagens

Abstract The antagonistic potential of Trichoderma strains was assayed by studying the effect of their culture filtrate on the radial growth of Sclerotium rolfsii, the causal agent of chickpea collar rot. Trichoderma harzianum-1432 (42.2%) and Trichoderma atroviride (40.3%) were found to be strong antagonists. To enhance their antagonistic potential, mutagenesis of these two selected strains was performed. Two mutants, Th-m1 and T. atroviride m1, were found to be more effective than their parent strains. The enzymatic activities of the selected parent and mutant strains were assayed, and although both mutants were found to have enhanced enzymatic activities compared to their respective parent strains, Th-m1 possessed the maximum cellulase (5.69 U/mL) and β-1,3-glucanase activity (61.9 U/mL). Th-m1 also showed high competitive saprophytic ability (CSA) among all of the selected parent and mutant strains, and during field experiments, Th-m1 was found to successfully possess enhanced disease control (82.9%).

Cultural conditions on the production of extracellular enzymes by Trichoderma isolates from tobacco rhizosphere

Abstract Twelve isolates of Trichoderma spp. isolated from tobacco rhizosphere were evaluated for their ability to produce chitinase and β-1,3-glucanase extracellular hydrolytic enzymes. Isolates ThJt1 and TvHt2, out of 12 isolates, produced maximum activities of chitinase and β-1,3-glucanase, respectively. In vitro production of chitinase and β-1,3-glucanase by isolates ThJt1 and TvHt2 was tested under different cultural conditions. The enzyme activities were significantly influenced by acidic pH and the optimum temperature was 30 °C. The chitin and cell walls of Sclerotium rolfsii, as carbon sources, supported the maximum and significantly higher chitinase activity by both isolates. The chitinase activity of isolate ThJt1 was suppressed significantly by fructose (80.28%), followed by glucose (77.42%), whereas the β-1,3-glucanase activity of ThJt1 and both enzymes of isolate TvHt2 were significantly suppressed by fructose, followed by sucrose. Ammonium nitrate as nitrogen source supported the maximum activity of chitinase in both isolates, whereas urea was a poor nitrogen source. Production of both enzymes by the isolates was significantly influenced by the cultural conditions. Thus, the isolates ThJt1 and TvHt2 showed higher levels of chitinase and β-1,3-glucanase activities and were capable of hydrolyzing the mycelium of S. rolfsii infecting tobacco. These organisms can be used therefore for assessment of their synergism in biomass production and biocontrol efficacy and for their field biocontrol ability against S. rolfsii and Pythium aphanidermatum infecting tobacco.

Determination of lytic enzyme activities of indigenous Trichoderma isolates from Pakistan

Abstract This study investigated lytic enzyme activities in three indigenous Trichoderma strains namely, Trichoderma asperellum, Trichoderma harzianum and Trichoderma sp. Native Trichoderma strains and a virulent strain of Rhizoctonia solani isolated from infected bean plants were also included in the study. Enzyme activities were determined by measuring sugar reduction by dinitrosalicylic acid (DNS) method using suitable substrates. The antagonists were cultured in minimal salt medium with the following modifications: medium A (1 g of glucose), medium B (0.5 g of glucose + 0.5 g of deactivated R. solani mycelia), medium C (1.0 g of deactivated respective antagonist mycelium) and medium D (1 g of deactivated R. solani mycelia). T asperellum showed presence of higher amounts of chitinases, β-1, 3-glucanases and xylanases in extracellular protein extracts from medium D as compared to medium A. While, the higher activities of glucosidases and endoglucanses were shown in medium D extracts by T. harzianum. β-glucosidase activities were lower compared with other enzymes; however, activities of the extracts of medium D were significantly different. T. asperellum exhibited maximum inhibition (97.7%). On the other hand, Trichoderma sp. did not show any effect on mycelia growth of R. solani on crude extract.

Morphological changes and growth of filamentous fungi in the presence of high concentrations of PAHs

In this study, we evaluated the effect of low and high molecular weight polycyclic aromatic hydrocarbons (PAHs), i.e., Phenanthrene, Pyrene and Benzo[a]pyrene, on the radial growth and morphology of the PAH-degrading fungal strains Aspergillus nomius H7 and Trichoderma asperellum H15. The presence of PAHs in solid medium produced significant detrimental effects on the radial growth of A. nomius H7 at 4,000 and 6,000 mg L⁻¹ and changes in mycelium pigmentation, abundance and sporulation ability at 1,000–6,000 mg L⁻¹. In contrast, the radial growth of T. asperellum H15 was not affected at any of the doses tested, although sporulation was observed only up to 4,000 mg L⁻¹ and as with the H7 strain, some visible changes in sporulation patterns and mycelium pigmentation were observed. Our results suggest that fungal strains exposed to high doses of PAHs significantly vary in their growth rates and sporulation characteristics in response to the physiological and defense mechanisms that affect both pigment production and conidiation processes. This finding is relevant for obtaining a better understanding of fungal adaptation in PAH-polluted environments and for developing and implementing adequate strategies for the remediation of contaminated soils.

Efficiency of treatments for controlling Trichoderma spp during spawning in cultivation of lignicolous mushrooms

Trichoderma spp is the cause of the green mold disease in mushroom cultivation production. Many disinfection treatments are commonly applied to lignocellulose substrates to prevent contamination. Mushroom growers are usually worried about the contaminations that may occur after these treatments during handling or spawning. The aim of this paper is to estimate the growth of the green mold Trichoderma sp on lignocellulose substrates after different disinfection treatments to know which of them is more effective to avoid contamination during spawning phase. Three different treatments were assayed: sterilization (121 ºC), immersion in hot water (60 and 80 ºC), and immersion in alkalinized water. Wheat straw, wheat seeds and Eucalyptus or Populus sawdust were used separately as substrates. After the disinfection treatments, bagged substrates were sprayed with 3 mL of suspension of conidia of Trichoderma sp (10(5) conidia/mL) and then separately spawned with Pleurotus ostreatus or Gymnopilus pampeanus. The growth of Trichoderma sp was evaluated based on a qualitative scale. Trichoderma sp could not grow on non-sterilized substrates. Immersions in hot water treatments and immersion in alkalinized water were also unfavorable treatments for its growth. Co- cultivation with mushrooms favored Trichoderma sp growth. Mushroom cultivation disinfection treatments of lignocellulose substrates influence on the growth of Trichoderma sp when contaminations occur during spawning phase. The immersion in hot water at 60 ºC for 30 min or in alkalinized water for 36 h, are treatments which better reduced the contaminations with Trichoderma sp during spawning phase for the cultivation of lignicolous species.

Molecular characterization of a Xylanase-producing fungus isolated from fouled soil

Xylanase (EC 3. 2. 1. 8), hydrolyzes xylo-oligosaccharides into D-xylose and required for complete hydrolysis of native cellulose and biomass conversion. It has broad range of applications in the pulp and paper, pharmaceutical and Agri-food industries. Fifty fungal species were isolated from the fouled soil around an oil refinery and screened for the production of xylanase enzyme by enrichment culture techniques. The isolated fungal strain was identified as Hypocrea lixii SS1 based on the results of biochemical tests and 18s rRNA sequencing. The phylogenetic tree was constructed using the MEGA 5 software. Further, Hypocrea lixii SS1 was tested for the ability to utilize the sunflower oil sludge (waste from the oil industry) as the sole carbon source for xylanase production. The growth characteristics of Hypocrea lixii SS1 were also studied and maximum growth was found on the 7th day of incubation. The fungus showed a remarkable xylanase production of 38.9 U/mL. Xylanase was purified using a combination of 0-50% NH4SO2 precipitation, DEAE-sepharose and Sephacryl S-200 chromatography. Single peak obtained in RP-HPLC confirms the purity of xylanase. Further the enzyme produced was affirmed as xylanase with its molecular weight (29 kDa) using SDS-PAGE.

Filamentous fungi and media for cellulase production in solid state cultures

Cellulase production was evaluated in two reference strains (T. reesei Rut-C30 and T. reesei QM9414), two strains isolated from a sugarcane cultivation area (Trichoderma sp. IPT778 and T. harzianum rifai IPT821) and one strain isolated in a program for biodiversity preservation in São Paulo state (Myceliophthora thermophila M77). Solid state cultures were performed using sugarcane bagasse (C), wheat bran (W) and/or soybean bran (S). The highest FPA was 10.6 U/gdm for M77 in SC (10:90) at 80% moisture, which was 4.4 times higher than production in pure W. C was a strong inducer of cellulase production, given that the production level of 6.1 U/gdm in WC (40:60) was 2.5 times higher than in pure W for strain M77; T. reesei Rut-C30 did not respond as strongly with about 1.6-fold surplus production. S advantageously replaced W, as the surplus production on SC (20:80) was 2.3 times relative to WC (20:80) for M77.

Exploitation of trichoderma species on the growth of Pythium Aphanidermatum in Chilli

Damping-off of chilli caused by Pythium aphanidermatum is a major nursery disease in vegetables. In vitro experiments evaluated the effect of eight isolates of Trichoderma species (from chilli rhizosphere) were tested against P. aphanidermatum. All the Trichoderma species had varied antagonistic effects against the pathogen. Among them, TVC3 recorded maximum growth inhibition of P. aphanidermatum and produced more amounts of volatile and non-volatile metabolites. The culture filtrate of the Trichoderma isolate TVC3 recorded complete inhibition on the mycelial growth of pathogen at 15 percent concentration. Moreover, chilli seeds treated with culture filtrate of the isolate TVC3 recorded maximum germination percentage, shoot length, root length and vigour index of chilli. The study identified the Trichoderma isolate (TVC3) performed well in inhibiting the mycelial growth of pathogen as well as increased the plant growth in chilli.

Comparative growth of trichoderma strains in different nutritional sources, using bioscreen c automated system / Crescimento de linhagens de Trichoderma em diferentes fontes nutricionais, empregando o sistema automatizado Bioscreen C

Trichoderma is one of the fungi genera that produce important metabolites for industry. The growth of these organisms is a consequence of the nutritional sources used as also of the physical conditions employed to cultivate them. In this work, the automated Bioscreen C system was used to evaluate the influence of different nutritional sources on the growth of Trichoderma strains (T. hamatum, T. harzianum, T. viride, andT. longibrachiatum) isolated from the soil in the Juréia-Itatins Ecological Station (JIES), São Paulo State - Brazil. The cultures were grown in liquid culture media containing different carbon- (2%; w/v) and nitrogen (1%; w/v) sources at 28ºC, pH 6.5, and agitated at 150 rpm for 72 h. The results showed, as expected, that glucose is superior to sucrose as a growth-stimulating carbon source in the Trichoderma strains studied, while yeast extract and tryptone were good growth-stimulating nitrogen sources in the cultivation of T. hamatum and T. harzianum.

Trichoderma é um dos gêneros de fungos produtores de metabólitos de interesse industrial. O crescimento destes organismos é conseqüência das fontes nutricionais utilizadas, juntamente com as condições físicas de cultivo. Neste trabalho, o sistema automatizado Bioscreen C foi utilizado para avaliar a influência de diferentes fontes nutricionais sobre o crescimentode linhagens de Trichoderma (T. hamatum, T. harzianum, T. viride e T. longibrachiatum) isoladas do solo da Estação Ecológica da Juréia-Itatins (JIES), São Paulo - Brasil. Os cultivosforam feitos em meios líquidos de cultura contendo diferentes fontes de carbono (2%; w / v) e nitrogênio (1%; w / v) a 28ºC, pH 6,5 e agitados a 150 rpm durante 72 h. Os resultados mostraram, conforme esperado, que a glicose é melhor do que a sacarose como fonte de carbono indutora de crescimento das linhagens de Trichoderma testadas, enquanto que, o extrato de leveduras e a triptona foram boas fontes de nitrogênio indutorasde crescimento para os cultivos de T. hamatum e T. harzianum.

Evaluación de sustratos y procesos de fermentación sólida para la producción de esporas de Trichoderma sp / Evaluating solid fermentation processes and substrates for producing Trichoderma sp. spores

Se evaluó un aislado nativo del hongo Trichoderma sp. en 13 sustratos y dos procesos de fermentación sólida.Se utilizaron sustratos sólidos a base de semillas de Artocarpus incisa (fruta de pan) y desechos agroindustriales como cascarilla de arroz y algodón. La mejor producción de esporas se registró en el sustrato compuesto por cascarilla de algodón (enriquecida con soluciones de melaza) y semillas de Artocarpus incisa con valores de concentración de esporas entre 2,1 x 108 conidios/g, y 8,38 x 108 conidios/g. Mientras que las más bajas concentraciones se presentaron en cascarilla de arroz. Los sustratos EA-5 (cascarilla de algodónenriquecida con solución de melaza 1 por ciento - Urea por ciento (5:1)) y E-FP-1 (cascarilla de algodón al 60 por ciento - semillas de Artocarpus incisa, al 40 por ciento) se diferenciaron significativamente del resto de los sustratos probados por presentar las más altas concentraciones. Se seleccionaron estos dos sustratos para evaluar dos procesos de producción masiva de esporas de Trichoderma sp. utilizando los procesos de fermentación sólida:artesanal y semi-industrial, este último caracterizado por suministro de aire con presión de 2L/min. Mediante conteos de conidias/g. del polvo cosechado en cámara de Neubauer, se determinó la concentración de esporas en cada uno de los sustratos, obteniéndose concentraciones para los procesos artesanal y semi-industrial de 2,53 x 109 y 2.31 x 109 conidios/g, respectivamente. Para estos procesos estadísticamenteno se encontraron diferencias significativas, indicando que la aireación aplicada para el proceso semi-industrial no tuvo incidencia relevante para mejorar la esporulación con respecto al proceso artesanal.

Greenhouse evaluation of Bacillus subtilis AP-01 and Trichoderma harzianum AP-001 in controlling tobacco diseases / Avaliação em estufa de dois agentes biológicos de controle de doenças do tabaco

Two biological control agents, Bacillus subtilis AP-01 (LarminarTM) and Trichoderma harzianum AP-001 (TrisanTM) alone or/in combination were investigated in controlling three tobacco diseases, including bacterial wilt (Ralstonia solanacearum), damping-off (Pythium aphanidermatum), and frogeye leaf spot (Cercospora nicotiana). Tests were performed in greenhouse by soil sterilization prior to inoculation of the pathogens. Bacterial-wilt and damping off pathogens were drenched first and followed with the biological control agents and for comparison purposes, two chemical fungicides. But for frogeye leaf spot, which is an airborne fungus, a spraying procedure for every treatment including a chemical fungicide was applied instead of drenching. Results showed that neither B. subtilis AP-01 nor T. harzianum AP-001 alone could control the bacterial wilt, but when combined, their controlling capabilities were as effective as a chemical treatment. These results were also similar for damping-off disease when used in combination. In addition, the combined B. subtilis AP-01 and T. harzianum AP-001 resulted in a good frogeye leaf spot control, which was not significantly different from the chemical treatment.

Dois agentes de controle biológico, Bacillus subtilis AP-01 (Larminar®) e Trichoderma harzianum AP-001 (Trisan®) foram avaliados separadamente ou em combinação quanto à capacidade de controlar três doenças do tabaco: murcha bacteriana (bacterial wilt, Ralstonia solanacearum), tombamento de mudas (damping-off, Pythium aphanidermatum), e mancha olho-de-rã (frogeye leaf spot, Cercospora nicotiana). Os testes foram realizados em estufa, esterilizando-se o solo antes da inoculação dos patógenos. Os patógenos causadores da murcha bacteriana e tombamento de mudas foram inicialmente encharcados e acompanhados com os agentes de controle biológico e, para comparação, com um fungicida químico. Para a mancha olho-de-rã, causada por um fungo anemófilo, utilizou-se um processo de spray ao invés do encharcamento. Os resultados indicaram que nenhum dos dois agentes de controle biológico, aplicado isoladamente, foi capaz de controlar a murcha bacteriana, mas quando em combinação a capacidade de controle foi similar ao do tratamento químico. Resultados semelhantes foram obtidos para o tombamento de mudas. Além disso, a combinação de Bacillus subtilis AP-01 e Trichoderma harzianum AP-001 resultou em um controle muito eficiente da mancha olho-de-rã, que não diferiu significativamente daquele obtido com o tratamento químico.

Sensibilidad in vitro de cepas de Trichoderma aisladas de semillas de soja frente al fungicida Maxim® XL / In vitro sensitivity to Maxim® XL fungicide in strains of Trichoderma isolated from soybean seeds

La utilización combinada de fungicidas a bajas dosis y cepas de Trichoderma tolerantes a los agroquímicos sería una estrategia aplicable para el manejo integrado del cultivo de soja. El objetivo del presente trabajo fue evaluar la sensibilidad in vitro de 3 cepas de Trichoderma aisladas de semillas de soja, frente a curasemilla Fludioxonil 2.5 por ciento + Metalaxil-M 1 por ciento(Maxim® XL). Se ensayaron 8 concentraciones de los ingredientes activos Fludioxonil 2.5 por ciento y Metalaxil-M 1 por ciento entre los rangos 10-5 a 102 ug/mL y 4.10-6 a 40 ug/mL, respectivamente. El fungicida se agregó al medio Agar Papa Glucosa 2 por ciento fundido, sembrándose un disco de agar con micelio en crecimiento activo en el centro de las placas de Petri. Se efectuaron mediciones del diámetro de las colonias cada 24 horas en 4 oportunidades. La concentración efectiva capaz de inhibir el crecimiento micelial en un 50 por ciento (CE50) fue calculada mediante la función de regresión de los valores de inhibición micelial en respuesta a las diferentes concentraciones expresadas logarítmicamente. Las cepas ensayadas fueron altamente sensibles al curasemilla estudiado, con valores de CE50 que variaron entre 8. 10-5 y 1.10-2 ug/mL, los que resultaron muy inferiores a la dosis agronómica del fungicida recomendada. Estos resultados indican que no sería compatible el uso conjunto del fungicida estudiado con los aislamientos de Trichoderma evaluados.

The combined use of low fungicide doses and Trichoderma strains that are resistant to agrochemical products would constitute a viable strategy for integrated soybean cultivation management. The aim of this work was to evaluate in vitro sensitivity to Fludioxonil 2.5 percent + Metalaxil-M 1 percent (MaximR XL) in 3 strains of Trichoderma isolated from soybean seeds. Eight concentrations of the active ingredient Fludioxonil 2.5 percent and Metalaxil-M 1 percent were tested, with a range of 10-5 to 102 ug/mL and 4.10-6 to 40 ug/mL, respectively. The fungicide was added to melted 2 percent Potate Glucose Agar medium, and sowing was carried out at the center of the Petri plates of an agar disk that contained fungus mycelium in active growth. Colony diameters were measured every 24 hours, on four successive occasions. The concentration capable of inhibiting mycelia growth by 50 percent (CE50) was calculated by means of the regression function of mycelial inhibition values obtained as response to different concentrations, which were expressed logarithmically. The three strains tested were highly sensitive to the seed treatment studied, with CE50 values that varied between 8.10-5 and 1.10-2 ug/mL, which are inferior to the agronomic dose recommended. These results indicated that the joint use of the fungicide and the Trichoderma isolates evaluated would not be compatible.

Respuesta in vitro de cepas de Trichoderma harzianum frente a Fe3+, salinidad, pH y temperatura, con el fin de ser utilizadas en control biológico de Rhizoctonia solani y Fusarium solani en tomate / In vitro response of Trichoderma harzianum strains to Fe3+, salinity, pH and temperature, in order to be used in the biological control of Rhizoctonia solani and Fusarium solani in tomatoe

Se investigó el grado de efectividad in vitro mediante antagonísmo directo, metabolitos volátiles y difusibles, así como la respuesta a Fe3+, salinidad, pH y temperatura de 4 cepas de Trichoderma harzianum, con el fin de utilizarse en el control biológico de Rhizoctonia solani y de Fusarium solani en tomate. Se determinó que la mejor cepa antagonista correspondió a T. harzianum Th 650, la que siempre fue más eficiente en el control de las cepas de R. solani que las de F. solani. Las cepas de T. harzianum evaluadas crecieron mejor a concentraciones bajas de Fe3+ y salinidad y a pH 5,0; sin embargo, estos factores no fueron limitantes para bioantagonizar a R. solani y a F. solani. Ninguna de las temperaturas fue limitante para el desarrollo de las cepas de T. harzianum, siendo 28ºC la más adecuada. Se determinó que la cepa Th 650 actúa mejor como bioantagonista a 28ºC y pH5. Si se consideran las caracteísticas de los suelos a aplicarse, los factores analizados no serían una limitante para su uso como un biocontrolador de los patógenos evaluados.

Gallotannin hydrolysis by immobilized fungal mycelia in a packed bed bioreactor.

Hydrolysis of gallotannin to gallic acid by immobilized mycelia of Aspergillus niger MTCC 282, Aspergillus fischerii MTCC 150, Fusarium solani MTCC 350 and Trichoderma viride MTCC 167 in a packed bed bioreactor was studied. Fungal mycelia preinduced with 5 g L-1 gallotannin were immobilized in calcium alginate gel (1.5%) and the resultant beads were packed in a column to a bed volume of 175 mm3. Gallotannin dissolved in distilled water was passed through the column and the eluate was recycled after adjusting pH to 6 with ammonium hydroxide (10%). Maximum hydrolysis of gallotannin was recorded by immobilized mycelia of F. solani and T. viride at 35 degrees and 45 degrees C after 175 and 60 min of residency period respectively. Optimum substrate concentration required for maximum hydrolysis was 10 g L-1 at pH 5 for both the fungi. Immobilized mycelia of A. niger and A. fischerii revealed maximum operational stability. Loss of activity after eighth run was in the order of-A. niger (no loss), A. fischerii (7.5%), F. solani (18%) and T. viride (18%). Stability in terms of retention of enzyme activity after 150 days of storage at 4 degrees C was A. niger (58%), A. fischerii (26.8%), F. solani (83%) and T. viride (85.1%).

In vitro antagonistic potential of trichoderma spp. against colletotrichum gloeosporioides agent of anthracnose in the passion fruit

Diecisiete cepas de trichoderma aisladas del suelo de plantaciones de pasionaria, fueron seleccionadas por su tasa de crecimiento y capacidad de esporulación, evaluándose su potencial antagónico sobre un aislamiento de c. gloeosporioides, agente de la antracnosis de la pasionaria. Mediante la utilización de la técnica de cultivos apareados se comprobó que todas las cepas de trichoderma causaron alteraciones morfofisiológicas en las hifas del fitopatógeno. Este tipo de actividad fue evidenciado por plasmolisis, vacuolización y eroscamiento de hifas. En 13 apareamiento hubo sobreposición de trichoderma sp., causando inhibición del crecimiento micelial de las colonias del fitopatógeno, no sobreviviendo este en 10 apareamientos. De las tres especies evaluadas t. koningii reunión el mayor número de aislamientos con características favorables para su utilización en el control biológico de c. gloeosporioides, lo que sugiere la posibilidad de controlar la antracnosis de esta planta en el campo

Produçäo e caracterizaçäo de celulases extracelular de uma linhagem termofílica do fungo Aspergillus sp / production and characterization of extracellular cellulases from a thermostable aspergillus sp

Uma linhagem termofílica do fungo Aspergillus sp., No.10-2, foi isolada de compostos.a faixa de temperatura para crescimento variou de 20 a 50ºC sendo que a temperatura ótima ficou entre 35 a 45ºC.As produçöes máximas de endo-1, 4-ß-D-glucanase EC.3.2.1.4 (CMCase), exo-1, 4-ß-D-cellobiohydrolase EC. 3.2.1.91 (Avicelase) e ß-glucosidase EC.3.2.1.21 (Celobiase)foram obtidas quando o fungo foi cultivado em meio líquido contendo papel de celulose em pó.A maior produçäo de CMCase foi obtida a 37ºC enquanto que uma extraordinária produçäo de ß-glucosidase ocorreu a 45ºC.A temperatura ótima de sacarificaçäo de celulose pela enzima foi 55ºC.Ensaios de cromatografia de papel de hidrolisados da celulose demonstraram predominantemente glicose quando comparado a hidrolisados de celulose obtidos por enzima de Trichoderma reesei QM 9414.Isto ocorreu porque a linhagem de Aspergillus sp., No.10-2, produziu maiores a enzima ß-glucosidase

Cellulase production by locally isolated trichoderma species

Production of cellulases by four different locally isolated species belonging to the genus Trichoderma was studied. The organisms were grown in a mineral salt medium containing 1% glucose, CMC, filter paper or Avicel in shake flasks. The order of cellulase productivity of the four species was T. harzianum > T. longibrachiatum > T. hamatum > T. piluliferum. The induction effect of different carbon sources was Avicel > filter paper > CMC > glucose for all the species. In the medium containing 1% Avicel T. harzianum produced 74.6, 11.5, 3.2 and 11.3 U of CMCase, avicelase, FPase and salicinase, respectively per 100 ml of the culture medium