Regina Teresa Rosim Monteiro

Plant bioassays to assess toxicity of textile sludge compost

Composting of industrial wastes is increasing because of recycling requirements set on organic wastes. The evaluation of toxicity of these wastes by biological testing is therefore extremely important for screening the suitability of waste for land application. The toxicity of a textile sludge compost was investigated using seed germination and plant growth bioassays using soybean and wheat. Compost samples were mixed with water (seed germination bioassay) or nutrient solution (plant growth bioassay) at concentrations of 0, 19, 38, 76 and 152 g L-1. No negative effects were observed after five days of compost water-extract in relation to soybean and wheat seed germination. After fifteen days, under a hydroponics system, plant growth had harmful effects of the compost at concentrations above 38 g L-1. Textile sludge compost presented great phytotoxicity under hydroponics condition and the soybean and wheat were sensitive for evaluation of organic wastes in plant growth bioassays.

Uso de agrotóxicos em cana-de-açúcar na bacia do Rio Corumbataí e o risco de poluição hídrica

The state of Sao Paulo is the main Brazilian consumer of pesticides. Sugar cane, which uses a great amount of these products, is extensivelly cultivated in this state, such as in the Corumbatai river basin, an important source of water for the region. In order to implement an efficient and low-cost monitoring program, the temporal characterization of the use of pesticides on sugar cane in this basin was performed. After knowing the seasonal trends of consumption, a better choice of sampling time, became possible. The combination of data from this survey with partitioning indices, average doses and toxicological classifications showed to be important for defining the pesticides to be included in the monitoring program.

Evaluation of sugar-cane vinasse treated with Pleurotus sajor-caju utilizing aquatic organisms as toxicological indicators

Toxicity tests with aquatic organisms constitute an effective tool in the evaluation, prediction and detection of the potential effect of pollutants from environmental samples in living organisms. Vinasse, a highly colored effluent, is a sub-product rich in nutrients, mainly organic matter, with high pollutant potential when disposed in the environment. Assays for vinasse decolorization were performed using the fungus Pleurotus sajor-caju CCB020 in vinasse biodegradation study, were occurred reductions of 82.8% in COD, 75.3% in BOD, 99.2% in the coloration and 99.7% in turbidity. The vinasse toxicity reduction was determined by the exposition to the following organisms: Pseudokirchneriella subcapitata, Daphnia magna, Daphnia similis and Hydra attenuata. This work concluded that the systematic combination of P. sajor-caju and vinasse can be applied in the bioprocess of color reduction and degradation of complex vinasse compounds, with reduction in the toxicity and improving its physical-chemical properties.

Diagnóstico espaço-temporal da ocorrência de herbicidas nas águas superficiais e sedimentos do Rio Corumbataí e principais afluentes

SPATIAL-TEMPORAL DIAGNOSTIC OF HERBICIDE OCCURRENCE IN SURFACE WATERS AND SEDIMENTS OF CORUMBATAI RIVER AND MAIN AFFLUENTS. Residues of herbicides from sugarcane were monitored in waters and sediments of Corumbatai River and tributaries. Ametryne, atrazine, simazine, hexazinone, glyphosate, and clomazone were detected in water samples, with negligible levels of ametryne and glyphosate in sediment samples. The area of recharge of the Guarani aquifer presented the highest triazine and clomazone levels. The triazines were detected at higher levels, with atrazine above Brazils potability and quality standards. Total herbicide levels at some sampling points were 13 times higher than the European Community potability limit. There is no Brazilian standard for ametryne, although the risk is larger due to ametrynes higher toxicity for the aquatic biota.

Biodegradação de efluente têxtil por Pleurotus sajor-caju

Effluents generated by the textile industry are of environmental concern because of the presence of dyes with complex molecular structure, which confer them recalcitrant characteristics. Indigo is one of the most widely used dyes within the textile sector and studies have suggested that edible fungi may be capable of its biodegradation. A textile effluent was mixed with sugarcane bagasse and inoculated with Pleurotus sajor-caju, the decolorization being evaluated after 14 days, when the process was observed. Enzymatic activities of laccase, peroxidase and manganese peroxidase were determined, the production of these ligninolytic enzymes being evident and a synergism among them being likely in the decolorizing process.

Use of vinasse and sugarcane bagasse for the production of enzymes by lignocellulolytic fungi

In this present work, three strains of Pleurotus an d Trichoderma reesei were cultivated in media with pre-treated bagasse and vinasse. Cellulolytic and lignolytic ac tivities and biomass production were analyzed. The treatment of the bagasse with 2% H 2O2 + 1.5% NaOH + autoclave resulted in a greater fibe r breakage increasing the cellulose level up to 1.2 times and decreasing 8.5 times the hemicellulose content. This treatment also resulted in a high lignolytic activity for all cultures utilized. T. reesei produced laccase, peroxidase and manganese-pe roxidase in all the treatments, having its manganese-peroxidase act ivity raging from 1.9 to 4.8 times higher than the basidiomycetes.

Isolation of diuron-degrading bacteria from treated soil

Studies were carried out on the isolation of diuron-degrading bacteria from treated soil. The mineralization of 14 Cdiuron in soil following a three-year application and in soil without previous application were 68.95 µg.100 g -1 and 24.16 µg.100 g -1 , respectively, after a 64-day incubation period. In the first soil there was a significant increase in the number of bacteria, from 3.3 x 10 6 to 1.9 x 10 8 . The microbial biomass did not change, however, a significant 14 C-residue of diuron was found in the microbial biomass. A consortium of three bacteria, Acinetobacter johnsonii and two Bacillus spp., was isolated in medium containing diuron as the only carbon source. Only A. johnsonii was able to grow alone in medium with diuron as the only carbon source.

Antimicrobial volatile organic compounds affect morphogenesis-related enzymes in Guignardia citricarpa, causal agent of citrus black spot.

Although non-volatile substances toxic to plant pathogenic microorganisms have been extensively studied over the years, few studies have focused on microbial volatile organic compounds (VOCs). The VOCs produced by the yeast Saccharomyces cerevisiae strain CR-1, used in fermentative processes for fuel ethanol production, are able to inhibit the vegetative development of the fungus Guignardia citricarpa, causal agent of the disease citrus black spot. How microbial VOCs affect the development of fungi is not known. Thus, the objective of the present work was to study the effect of the artificial mixture of VOCs identified from S. cerevisiae on intracellular enzymes involved in the mycelial morphogenesis in G. citricarpa. The phytopathogenic fungus was exposed to artificial mixture of VOCs constituted by alcohols (ethanol, 3-methyl-1-butanol, 2-methyl-1-butanol and phenylethyl alcohol) and esters (ethyl acetate and ethyl octanoate) in the proportions naturally found in the atmosphere produced by the yeast. The VOCs inhibited considerably the mycelial development and interfered negatively with the production of the morphogenesis-related enzymes. After 72 h of exposure to the VOCs the laccase and tyrosinase activities decreased 46 and 32%, respectively, however, the effect on the chitinase and β-1,3-glucanase activities was lower, 17 and 13% of inhibition, respectively. Therefore, the exposure of the fungus to the antimicrobial volatiles can influence both fungal mycelial growth rate and activity of enzymes implicated in morphogenesis. This knowledge is important to understand the microbial interactions mediated by VOCs in nature and to develop new strategies to control plant pathogens as G. citricarpa in postharvest.

Ecotoxicological assessment of water and sediment of the Corumbataí River, SP, Brazil

The Corumbataí River drains an economically important area which is mainly represented by the municipalities of Piracicaba and Rio Claro. In view of the impacts caused by the discharge of industrial waste and domestic sewage into the Piracicaba River, the Corumbataí has become increasingly significant as a source of water for the municipality of Piracicaba. However, chemical, physical, and microbiological analyses carried out prior to the present study had already indicated a decline in the quality of the Corumbataí waters. This study aimed to assess, through water and sediment samples, both acute and chronic toxicity to Daphnia magna and Daphnia similis, and to analyze acid-volatile sulfide (AVS) and simultaneously extracted metal (SEM) in the sediment. Resulting data were intended to be a contribution to future projects for the management and recuperation of this system. To that aim, water and sediment were collected at seven Corumbataí sampling stations in November 2003 and March 2004. Acute toxicity to D. similis was detected in water and sediment samples from the Piracicaba station, located at the mouth of the Corumbataí River. Chronic toxicity was identified in the water or sediment samples of all stations, with the exception of Analândia Montante (upstream), at the head of the river. This was found to affect survival, growth, and fecundity of the test-organisms. The AVS and SEM analyses showed the bioavailability of the metals, thus explaining toxicity found in bioassaying samples of water and sediment. The use of two test-organism species made it possible to obtain a better assessment of the condition of both water and sediment samples of the Corumbataí River.

Optimization of lipids production by Cryptococcus laurentii 11 using cheese whey with molasses

This study aimed the optimization of culture condition and composition for production of Cryptococcus laurentii 11 biomass and lipids in cheese whey medium supplemented with sugarcane molasses. The optimization of pH, fermentation time, and molasses concentration according to a full factorial statistical experimental design was followed by a Plackett-Burman experimental design, which was used to determine whether the supplementation of the culture medium by yeast extract and inorganic salts could provide a further enhancement of lipids production. The following conditions and composition of the culture medium were found to optimize biomass and lipids production: 360 h fermentation, 6.5 pH and supplementation of (g L−1): 50 molasses, 0.5 yeast extract, 4 KH2PO4, 1 Na2HPO4, 0.75 MgSO4·7H2O and 0.002 ZnSO4·H2O. Additional supplementation with inorganic salts and yeast extract was essential to optimize the production, in terms of product concentration and productivity, of neutral lipids by C. laurentii 11. Under this optimized condition, the production of total lipids increased by 133% in relation to control experiment (from 1.27 to 2.96 g L−1). The total lipids indicated a predominant (86%) presence of neutral lipids with high content of 16- and 18-carbon-chain saturated and monosaturated fatty acids. This class of lipids is considered especially suitable for the production of biodiesel.