Robson Andreazza

Use of High-Yielding Bioenergy Plant Castor Bean (Ricinus communis L.) as a Potential Phytoremediator for Copper-Contaminated Soils

Abstract Copper (Cu) contamination in the environment has been increased during the years with agricultural and industrial activities. Biotechnological approaches are needed for bioremediation in these areas. The aims of this study were i) to evaluate the phytoremediation capacity of the high-yielding bioenergy plant castor bean (Ricinus communis L.) in vineyard soils (Inceptisol and Mollisol) contaminated with Cu and a Cu mining waste; ii) to characterize the castor bean as a Cu phytoremediation plant; and iii) to evaluate the nutrient uptake by castor bean. Castor bean plants cultivated in soil with toxic levels of Cu for 57 d exhibited high phytomass production, a high tolerance index of roots fresh mass and shoots dry mass, a high level of Cu phytoaccumulation in the roots and also, a robust capacity for Cu phytostabilization. Furthermore, castor bean plants did not significantly deplete soil nutrients (such as N, P, and Mg) during cultivation. Plants cultivated in Inceptisol, Mollisol and Cu mining waste exhibited a strong potential for Cu phytoaccumulation, with values of 5 900, 3 052 and 2 805 g ha−1, respectively. In addition, the castor beans elevated phytomass production and strong growth in Cu-contaminated soils indicated a high level of Cu phytoaccumulation and a potential application in biofuels. These findings indicate that the castor bean is a efficient hyperaccumulator of Cu and a potential candidate plant for the phytoremediation of Cu-contaminated soil.

Enzymatic activity of catechol 1,2-dioxygenase and catechol 2,3-dioxygenase produced by Gordonia polyisoprenivorans

This study aimed to evaluate the environmental conditions for enzyme activity of catechol 1,2-dioxygenase (C1,2O) and catechol 2,3-dioxygenase (C2,3O) produced by Gordonia polyisoprenivorans in cell-free and immobilized extracts. The optimum conditions of pH, temperature, time course and effect of ions for enzyme activity were determined. Peak activity of C1,2O occurred at pH 8.0. The isolate exhibited the highest activity of C2,3O at pH 7.0 and 8.0 for the cell-free extract and immobilized extract, respectively. This isolate exhibited important characteristics such as broad range of pH, temperature and time course for enzyme activity.

Capability of a selected bacterial consortium for degrading diesel/biodiesel blends (B20): Enzyme and biosurfactant production

The search for alternative sources of energy, such as biodiesel, has been stimulated, since this biofuel is highly susceptible for biodegradation and has low toxicity, thus, reducing the impact in ecosystems. The objective of this study was to select a bacterial consortium with potential for degrading diesel/biodiesel blends (B20) obtained from areas contaminated with hydrocarbons/esters. In order to evaluate the biodegrability of the blend, six enzyme assays were conducted: alkane hydroxylase, Catechol 1,2-dioxygenase, Catechol 2,3-dioxygenase, Protocatechol 3,4-dioxygenase, ρ-NPA hydrolysis (esterase), and release of fatty acids through titration (lipase), with estimative of total protein and biosurfactant production (surface tension measurement and emulsifying index E24). The best results obtained allowed the selection of four bacteria isolates (Bacillus megaterium, Bacillus pumilus, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia) for compiling a consortium, which will be used for bioaugmentation strategies in soils contaminated with these fuels. This consortium exhibited high potential for biodegradation of biodiesel, and might be an efficient alternative for cleaning up these contaminated environments.

Properties of catechol 1,2-dioxygenase in the cell free extract and immobilized extract of Mycobacterium fortuitum

Polycyclic aromatic hydrocarbons (PAH) are carcinogenic compounds which contaminate water and soil, and the enzymes can be used for bioremediation of these environments. This study aimed to evaluate some environmental conditions that affect the production and activity of the catechol 1,2-dioxygenase (C12O) by Mycobacterium fortuitum in the cell free and immobilized extract in sodium alginate. The bacterium was grown in mineral medium and LB broth containing 250 mg L−1 of anthracene (PAH). The optimum conditions of pH (4.0–9.0), temperature (5–70 °C), reaction time (10–90 min) and the effect of ions in the enzyme activity were determined. The Mycobacterium cultivated in LB shown higher growth and the C12O activity was two-fold higher to that in the mineral medium. To both extracts the highest enzyme activity was at pH 8.0, however, the immobilized extract promoted the increase in the C12O activity in a pH range between 4.0 and 8.5. The immobilized extract increased the enzymatic activity time and showed the highest C12O activity at 45 °C, 20 °C higher than the greatest temperature in the cell free extract. The enzyme activity in both extracts was stimulated by Fe3+, Hg2+ and Mn2+ and inhibited by NH4+ and Cu2+, but the immobilization protected the enzyme against the deleterious effects of K+ and Mg2+ in tested concentrations. The catechol 1,2-dioxygenase of Mycobacterium fortuitum in the immobilized extract has greater stability to the variations of pH, temperature and reaction time, and show higher activity in presence of ions, comparing to the cell free extract.

Avaliação in vitro do potencial antioxidante de frutas e hortaliças

O efeito protetor exercido por frutas e hortalicas tem sido atribuido a presenca de compostos antioxidantes. Objetivou-se, neste estudo, avaliar in vitro a capacidade antioxidante de um grupo de frutas e hortalicas, cruas e cozidas, atraves da diminuicao da peroxidacao lipidica, induzida por ferro em figado de ratos. Foram utilizados figados de ratos homogeneizados, que foram submetidos a oxidacao pelo ferro. As frutas e hortalicas foram utilizadas como antioxidantes, a fim de combater o estresse oxidativo induzido pelo ferro. O metodo utilizado neste trabalho foi a Reacao ao Acido Tiobarbiturico (TBARS), tendo como marcador para avaliar o estresse oxidativo o Malonaldeido (MDA). De acordo com os resultados obtidos, observou-se que houve uma diminuicao significativa do estresse oxidativo no grupo das frutas e das hortalicas cruas e cozidas com ferro, quando o figado foi submetido a oxidacao deste micronutriente. No grupo das frutas e das hortalicas cruas e cozidas sem ferro, ocorreu reducao significativa do estresse oxidativo, apenas em determinadas frutas e hortalicas. O consumo de uma dieta rica em frutas e hortalicas contribui com a defesa antioxidante do organismo, inibindo danos oxidativos em macromoleculas in vitro.

Potential Phytoextraction and Phytostabilization of Perennial Peanut on Copper-Contaminated Vineyard Soils and Copper Mining Waste

This study sought to evaluate the potential of perennial peanut (Arachis pintoi) for copper phytoremediation in vineyard soils (Inceptisol and Mollisol) contaminated with copper and copper mining waste. Our results showed high phytomass production of perennial peanut in both vineyard soils. Macronutrient uptakes were not negatively affected by perennial peanut cultivated in all contaminated soils. Plants cultivated in Mollisol showed high copper concentrations in the roots and shoots of 475 and 52xa0mgxa0kg−1, respectively. Perennial peanut plants showed low translocation factor values for Cu, although these plants showed high bioaccumulation factor (BCF) for both vineyard soils, Inceptisol and Mollisol, with BCF values of 3.83 and 3.24, respectively, being characterized as a copper hyperaccumulator plant in these soils. Copper phytoextraction from Inceptisol soil was the highest for both roots and entire plant biomass, with more than 800xa0mgxa0kg−1 of copper in whole plant. The highest potential copper phytoextraction by perennial peanut was in Inceptisol soil with copper removal of 2,500xa0gxa0ha−1. Also, perennial peanut showed high potential for copper phytoremoval in copper mining waste and Mollisol with 1,700 and 1,500xa0g of copper per hectare, respectively. In addition, perennial peanuts characterized high potential for phytoextraction and phytostabilization of copper in vineyard soils and copper mining waste.

The effects of trace elements, cations, and environmental conditions on protocatechuate 3,4-dioxygenase activity

Phenanthracene is a highly toxic organic compound capable of contaminating water and soils, and biodegradation is an important tool for remediating polluted environments. This study aimed to evaluate the effects of trace elements, cations, and environmental conditions on the activity of the protocatechol 3,4-dioxygenase (P3,4O) enzyme produced by the isolate Leifsonia sp. in cell-free and immobilized extracts. The isolate was grown in Luria Bertani broth medium (LB) amended with 250 mg L-1 of phenanthrene. Various levels of pH (4.0-9.0), temperature (5-80 °C), time (0-90 min), trace elements (Cu2+, Hg2+ and Fe3+), and cations (Mg2+, Mn2+, K+ and NH4+) were tested to determine which conditions optimized enzyme activity. In general, the immobilized extract exhibited higher enzyme activity than the cell-free extract in the presence of trace elements and cations. Adding iron yielded the highest relative activity for both cell-free and immobilized extracts, with values of 16 and 99 %, respectively. Copper also increased enzyme activity for both cell-free and immobilized extracts, with values of 8 and 44 %, respectively. Enzyme activity in the phosphate buffer was high across a wide range of pH, reaching 80 % in the pH range between 6.5 and 8.0. The optimum temperatures for enzyme activity differed for cell-free and immobilized extracts, with maximum enzyme activity observed at 35 oC for the cell-free extract and at 55 oC for the immobilized extract. The cell-free extract of the P3,4O enzyme exhibited high activity only during the first 3 min of incubation, when it showed 50 % relative activity, and dropped to 0 % after 60 min of incubation. By contrast, activity in the immobilized extract was maintained during 90 min of incubation. This isolate has important characteristics for phenanthrene biodegradation, producing high quantities of the P3,4O enzyme that forms part of the most important pathway for PAH biodegradation.

DECOMPOSIÇÃO DE RESÍDUOS INDUSTRIAIS NO SOLO

Waste disposal in soils is an efficient alternative to reduce environmentalnegative impact of industrial wastes and can be used as an important nutrientssource for the plants. Thus, the aim of this study was to evaluatethe decomposition rate of four industrial wastes applied in two differentsoils (Oxisol and Ultisol). The industrial wastes of treatment station were:(brewery – CERV; dairy products – LAT; plywood – AGL and textile – TEXT).It was evaluated the decomposition of the doses of these wastes throughthe microbial activity and N mineralization. The organic wastes evaluatedcan be used in agricultural soils, although, should be used nitrogen as additionalfertilization. The rate of the decomposition of the wastes in the bothevaluated soils, for the C-CO2 release and for the N accumulation in thesoils, increased in the following order: TEXT >LAT>CERV>AGL.

QUALIDADE BIOLÓGICA DO SOLO DE SISTEMAS DE CULTIVO EM POMARES DE CITRUS DELICIOSA

The citrus production is grown in Rio Grande do Sul under different croppingsystems, and their impact on soil quality is unknown. The aim of thisstudy was to evaluate some measures of environmental quality between differentmanagement systems of Citrus from Vale do Cai, RS with emphasison the production of tangerines ‘Montenegrina’ (Citrus deliciosa Tenore) bychemical and biological characterization of soils. The samples were collectedfrom five areas cultivated under different cropping types: organic cropping(PO), organic cropping in transition to biodynamic (POT), agroforestry cropping(PAF), conventional cropping (PC) and native forestry (MN) as a controltreatment in the Montenegro city, Rio Grande do Sul, at 0-10 cm of depth. Wedetermined the microbial biomass carbon (CBM), basal respiration (RB), theactivities of urease, acid phosphatase (FA) and the hydrolysis of fluoresceindiacetate (FDA). For all evaluations, the results were significantly higher inthe control area (MN). In CBM evaluations, the control obtained values of175.2 mg C Kg-1 of dry soil and the lowest value was found in CP at 34 mg CKg-1 of dry soil. The values of RB to system PAF (334.4 mg C-CO2 kg-1 of dryxa0soil), PO (333.3 mg C-CO2 kg-1 of dry soil) and LPO (257.7 mg C-CO2 kg-1 soildried) were significantly lower against the control (728.7 mg C-CO2 kg-1 drysoil). In the urease evaluation, the systems POT and PO were significantlylower with values of 77.7 and 68.5 µg N-NH4 g-1 of dry soil 2 h-1 respectively,compared with the control (128 µg N-NH4 g-1 of dry soil 2 h-1). For croppingxa0systems of PC and PAF, FA values obtained were almost three folds lower(541 and 427 µg p-nitrofenol g-1 dry soil h-1 respectively) when compared withthe control area. So the cropping systems, even the less intensive, were notable to maintain the same quality of soil microbiology that areas of the nativeforestry. This shows that soil quality indicators such as RB, the FA and ureasecan be important indicators in assessing the environmental quality of differentcropping systems of Citrus deliciosa.

DECOMPOSIÇÃO DE RESÍDUOS DE AGROINDÚSTRIA FUMAGEIRA NO SOLO

The industrial processing of tobacco produces around 35,000 tones of wastes per year. Furthermore, these wastes do not have commercial value and cause environmental problems. Thus, the aim of this study was evaluate the potential use to agricultural recycling of two main types of agro waste tobacco (AWT) and their soil mineralization in different conditions. Twelve treatments were used with increasing additions of AWT in dust (AWT D) and in stems (AWT S) and mineral fertilization. The mineralization of AWT, evaluated by the C-CO 2 evolution was up to 40% with AWT D and 49% with the AWT S. After AWT addition, it was observed high mineralization of nitrogen and increase of the soil pH. Hence, the addition of AWT can be an efficient alternative to promote the nutritional and physical conditions of soils with low cost.