Screening mitosporic fungi for organochlorides degradation

Fifty-five isolates of filamentous fungi were studied regarding their ability to decolorize Remazol brilliant blue R dye. The fungi were isolated from soil in the Baixada Santista region, which is contaminated with industrial residues containing a mixture of organochlorine compounds, mainly hexachlorobenzene. The fungi were grown in liquid malt extract medium with 0.02 percent of dye and shaken at 200 rpm for 14 days at 28 ± 2°C. Two types of behavior regarding the dye were observed: adsorption and degradation. Eupenicillium baarnenseSsp1951 and Ssp1952 and Eupenicilliumcrustaceum SSP1953 presented high RBBR decolorization and were then analyzed regarding their ability to degrade 14C-hexachlobenzene (4138.31 mg HCB per kg soil) during a 56 days culture at 28 ± 2°C. Eupenicillium crustaceum SSP1953 was able to reduce n-hexane soluble 14C-compounds (24.6 percent) and to form non-extractable 14C-residues (20.5 percent). The same behavior was also observed in the two E. baarnense strains (Ssp1951 and Ssp1952) but the percentages were lower than those obtained for Eupenicilliumcrustaceum. The main action of Eupenicillium spp on HCB is to transform it into non-extractable 14C-residues as confirmed by the gas chromatography results.

Cinqüenta e cinco isolados de fungos filamentosos foram avaliados quanto a capacidade de descolorir o corante remazol brilliant blue R. Estes fungos foram isolados de solos da Região da Baixada Santista contaminados com resíduos industriais contendo uma mistura de organoclorados, principalmente hexaclorobenzeno. O crescimento dos fungos foi realizado em meio líquido de extrato de malte contendo 0,02 por cento do corante, sob agitação de 200 rpm, durante 14 dias a 28°C ± 2. Foi possível verificar, entre os fungos avaliados, dois comportamentos em relação ao corante: adsorção e degradação. Eupenicillium baarnense SSp1951 e sSp1952 e Eupenicilliumcrustaceum SSP1953 apresentaram altas porcentagens de descoloração do RBBR. Estes fungos foram, então, avaliados quanto a sua capacidade de degradar 14C-hexaclorobenzeno (4138,31 mg de hexaclorobenzeno kg-1 de solo) durante 56 dias a 28°C ± 2. Eupenicillium crustaceum SSP1953 foi capaz de reduzir em 24,6 por cento os 14C-compostos solúveis em n-hexano e formar 20,5 por cento de 14C-resíduos não extraíveis. As duas linhagens de E. baarnense (Ssp1951 e Ssp1952) também apresentaram o mesmo comportamento, porém com porcentagens inferiores à observada para Eupenicillium crustaceum. A principal ação de Eupenicillium spp sobre hexaclorobenzeno foi transformá-lo em 14C-resíduos não extraíveis, como comprovaram os resultados da cromatografia gasosa.

Successive cultivation of maize and agricultural practices on root colonization, number of spores and species of arbuscular mycorrhizal fungi

A large number of propagules and a broad spectrum of species are two important components of ecosystem (including agroecosystem) sustainability. Previous studies carried out in temperate areas showed that repeated monoculture leads to a decrease in the species abundance of arbuscular mycorrhizal fungi (AMF). This study evaluated the influence of maize monoculture and its agricultural practices on AMF during three consecutive cropping years in a Brazilian field. At the end of each cycle, soil and root samples were evaluated for species composition, spore populations and root colonization by AMF. The AMF community present during this period was scored according to the Spearman rank correlation and Principal Components Analysis. The mean percent root colonization values for the three cultivation values for the three cultivation periods were: 66.9,60.7 and 70.5, respectively. Seven species were detected in the first year, Scutellospora persica being the most abundant 24.1 (per cent of spores) and Glomus macrocarpum the most observed 100 (per cent of samples). In the second year, Glomus etunicatum was the species with the greatest number of spores 24.7 (per cente and, like G. macrocarpum, the mostfrequently observed 90 per cente in a community of thirteen. In the third year, twenty-three AMF species were identified, Scutellospora sp.1 being the most abundant 17.4(per cent), and Gigaspora decipiens and Glomus claroideum the most frequent (both with a relative frequency of 70 (per cente). The main soil factors influencing root colonization and sporulation by AMF were pH (and related properties), phosphorus and organic matter contents.

Cultivation of the Edible mushroom Oudemansiella Canarii (Jungh.) HÖhn. in Lignocellulosic substrates

The edible mushroom Oudemansiella canarii (Jungh.) Höhn is common in the Brazilian territory, being found in different biomas, where they colonize several plant species. In this study, the O. canarii cultivation was evaluated in polypropilene bags containing sugar-cane bagasse (200 g) or eucalyptus sawdust (200 g) supplemented with wheat bran (50 g). The composts were sterilized at 121§C for 1 hour, after cooling they were inoculated with 3 g of spawn and then remained incubated at 25§C until the basidiomata primordia formation. The mushrooms, harvested after the pilei opening, presented varied sizes reaching 9 cm of diameter and 10 cm of height. The fresh mushrooms presented mild taste and soft consistency. When kept at 4§C, they maintained good appearance and good consistency for 7 days. In a period of 60 days, the largest basidiomata production was obtained in the compost with sugar-cane bagasse, showing greater productivity (4.47per cent ñ 1.34), biological efficiency (55.66per cent ñ 20.41) and compost consumption (38.78per cent ñ 4.59) averages. Wilcoxon's non-parametric statistical analysis used to compare the biomass production in the two composts, showed significant differences at 5 per cent significance level.