Cultivo de Batis maritima, Sarcocornia ambigua e Sporobolus virginicus com água residuária do cultivo de Litopenaeus vannamei

As águas residuárias de carcinicultura descartadas diretamente no ambiente podem provocar diversos impactos para a estabilidade dos ecossistemas adjacentes. Nesta perspectiva, este trabalho compara: o crescimento de plantas halófitas cultivadas com água residuária do cultivo de camarão e com água bruta de um estuário; a interação entre o cultivo integrado de plantas halófitas com camarões em sistemas de recirculação de água; e as medidas de variáveis físico-químicas das águas residuárias antes e após serem submetidas a um sistema de tratamento com plantas halófitas. Para tanto, foram realizados dois experimentos de bancada utilizando caixas de fibra para o cultivo das halófitas. Em ambos os experimentos foram realizadas medições semanais do crescimento e das massas inicial e final das plantas. As taxas de crescimento relativo e absoluto foram mensuradas para a massa e a altura das espécies vegetais. As taxas de crescimento absoluto para a massa da espécie Batis maritima dos sistemas um e dois do experimento 1 e do sistema com plantas do experimento 2 foi, respectivamente, 1,12 cm/d, 4,40 cm/d e 3,55 cm/d. Os dados indicaram que halófitas cultivadas com águas residuárias de carcinicultura apresentam crescimento maior, assim como são reduzidos os nutrientes do meio de cultivo na presença das plantas

Immobilization of microbial cells: A promising tool for treatment of toxic pollutants in industrial wastewater

The review articles on cell immobilization have been published since 1980 and reflect the general interest in this topic. Immobilized microbial cells create opportunities in a wide range of sectors including environmental pollution control. Compared with suspended microorganism technology, cell immobilization shows many advantages, such as resistance to toxic chemicals. This review presents the potential of immobilized microbial cells for treatment of toxic pollutants in industrial wastewater, the fundamentals, history and advantages of immobilized cells compared with suspended cells, characteristics of support materials and the principal methods of immobilization, with special emphasis for natural immobilization by cell adsorption.Keywords: Cell immobilization, microorganisms, adsorption, toxic pollutants, wastewaterAfrican Journal of Biotechnology Vol. 12(28), pp. 4412-441

Facilitation as Attenuating of Environmental Stress among Structured Microbial Populations

There is currently an intense debate in microbial societies on whether evolution in complex communities is driven by competition or cooperation. Since Darwin, competition for scarce food resources has been considered the main ecological interaction shaping population dynamics and community structure both in vivo and in vitro. However, facilitation may be widespread across several animal and plant species. This could also be true in microbial strains growing under environmental stress. Pure and mixed strains of Serratia marcescens and Candida rugosa were grown in mineral culture media containing phenol. Growth rates were estimated as the angular coefficients computed from linearized growth curves. Fitness index was estimated as the quotient between growth rates computed for lineages grown in isolation and in mixed cultures. The growth rates were significantly higher in associated cultures than in pure cultures and fitness index was greater than 1 for both microbial species showing that the interaction between Serratia marcescens and Candida rugosa yielded more efficient phenol utilization by both lineages. This result corroborates the hypothesis that facilitation between microbial strains can increase their fitness and performance in environmental bioremediation

Selection of culturable environmental microbial strains for cellular immobilization: Association of phenotypic adhesive characteristics and quantitative cellular retention

Environmental pollution by organic compounds is a global problem. Biological treatment methods are used to restore polluted environments. Microbial immobilization on abiotic surfaces is a recent strategy to improve the efficiency of these processes. In this technique, cell adhesion is a fundamental step for subsequent colonization and biofilm formation. Therefore, the use of strains with adhesive properties is a critical factor for successful immobilization. In this work, culturable environmental microbial strains were phenotypically characterized regarding their hydrophobicity, adhesion to polystyrene and production of exopolysaccharides and amyloid fibers. The cell retention was quantified by counting viable cells using polyurethane foam as material support. The degree of hydrophobicity varied from moderately hydrophobic to hydrophilic, while the adhesion to polystyrene and production of exopolysaccharides and amyloid fibers ranged from strong to negative. The results of qualitative tests were transformed into scores and a direct relationship between the qualitative characteristics and number of adhered cells on polyurethane foam was observed. The Gram-negative bacterium Serratia marcescens and the yeast Candida rugosa showed the best results and were selected for further immobilization tests.Key words: Hydrophobicity, cell adhesion, cell immobilization, Serratia marcescens, Candida rugosa

Cultivo de Batis maritima, Sarcocornia ambigua e Sporobolus virginicus com água residuária do cultivo de Litopenaeus vannamei

Shrimp wastewater discarded directly into the environment can impact the stability of adjacent ecosystems. This study evaluated the following: the growth of halophytes cultivated with shrimp culture water and water from an estuary; the interaction between the integrated cultivation of halophytes and shrimp in water recirculation systems; and physicochemical variables of wastewater before and after being treated with halophytes. Two bench experiments were carried out using fiber boxes to cultivate the halophytes. In both experiments, growth and initial and final mass of the plants were measured weekly. The relative and absolute growth rates were measured for the mass and height of the plant species. The absolute growth rates for Batis maritima of systems one and two of the first experiment, and of the system of plants of the second experiment, were 1.12 cm/d, 4.40 cm/d and 3.55 cm/d, respectively. The data indicated that halophytes cultivated with shrimp wastewater had higher growth and that the nutrients of the culture medium were reduced in the presence of plants.As águas residuárias de carcinicultura descartadas diretamente no ambiente podem provocar diversos impactos para a estabilidade dos ecossistemas adjacentes. Nesta perspectiva, este trabalho compara: o crescimento de plantas halófitas cultivadas com água residuária do cultivo de camarão e com água bruta de um estuário; a interação entre o cultivo integrado de plantas halófitas com camarões em sistemas de recirculação de água; e as medidas de variáveis físico-químicas das águas residuárias antes e após serem submetidas a um sistema de tratamento com plantas halófitas. Para tanto, foram realizados dois experimentos de bancada utilizando caixas de fibra para o cultivo das halófitas. Em ambos os experimentos foram realizadas medições semanais do crescimento e das massas inicial e final das plantas. As taxas de crescimento relativo e absoluto foram mensuradas para a massa e a altura das espécies vegetais. As taxas de crescimento absoluto para a massa da espécie Batis maritima dos sistemas um e dois do experimento 1 e do sistema com plantas do experimento 2 foi, respectivamente, 1,12 cm/d, 4,40 cm/d e 3,55 cm/d. Os dados indicaram que halófitas cultivadas com águas residuárias de carcinicultura apresentam crescimento maior, assim como são reduzidos os nutrientes do meio de cultivo na presença das plantas

Bioavailability of crude protein and lipid from biofloc meals produced in an activated sludge system for white shrimp, Litopenaeus vannamei

The present study compared the bioavailability of crude protein and lipid from biofloc meals generated with an activated sludge system using two water sources: wastewater from shrimp experimental culture (BFL-W) and, artificially, using clean seawater (BFL-C). The sludge system operated by chemical and organic fertilization three times per week. Sampling of bioflocs occurred every two days during 81 days. To evaluate digestibility, each type of biofloc meal was incorporated into a reference diet (REF) at 300 g/kg. Another diet acted as a negative control (NEG) by using fish waste meal. The apparent digestibility of bioflocs was estimated by the indirect method using chromic oxide (Cr2O3) as the inert marker at 10 g/kg of the diet. Juvenile L. vannamei of 5.09±0.79 g (n = 440) were stocked at 10 shrimp/tank in 44 tanks of 61 L each that operated under a water recirculating regime. Biofloc meals contained a high ash content (591.0-649.2 g/kg) combined with a low crude protein content (95.9-137.3 g/kg). After 26 days, shrimp achieved a final survival of 93.2±0.8% and a biomass gain of 37.1±1.8 g/tank. Final shrimp body weight ranged from 9.01±0.15 to 9.45±0.13 g. The apparent digestibility coefficient (ADC) of crude protein in the biofloc produced from BFL-W, BFL-C and fish waste meal (NEG) reached 26.0, 25.7, and 64.1%, respectively. Similarly, the lipid ADC was 78.9, 67.9, and 85.8%, respectively. This study indicated that biofloc meals had a low protein availability for L. vannamei. However, although low levels of lipid were present, it proved to be available for the species. The dietary inclusion of biofloc meal appears to have a growth-promoting effect on shrimp, which may be associated with trace minerals, or other nutrients not identified in this study

Influence of rainfall on the trophic status of a brazilian semiarid reservoir - doi: 10.4025/actascibiolsci.v35i4.18261

This study evaluated the trophic conditions of the reservoir located in the urban perimeter of the town General Sampaio, semiarid region of the Ceará State, Brazil and its relationship with seasonal variation in rainfall between 2010 and 2011. It was obtained data for Secchi disk transparency, total phosphorus, and chlorophyll a to calculate the Trophic State Index (TSI), as well as rainfall data. The Trophic State Index (TSI) proposed by Carlson (1977) and modified by Toledo Junior (1990) was used to test the influence of the seasonal variation in rainfall on hydrological variables and on trophic conditions of the reservoir in 2010 and 2011. There was seasonal variability in variables analyzed between climatic periods (rainy and dry) and trophic conditions determined through the trophic index indicated conditions ranging from oligotrophic to eutrophic during the two years analyzed in this reservoir. Under these circumstances, one may conclude that the trophic status is related to seasonal fluctuations in the hydrology of the system controlled by rainfall, which is a common feature of semiarid regions.

Remoção de compostos nitrogenados de águas residuárias de refinarias de petróleo através de reatores biológicos com fungos.

The presence of nitrogenous compounds in effluent of petroleum refineries and with concentrations above legal limits is a known serious environmental problem. The proposal of this research was to evaluate the removal of nitrogen compounds (ammonia, nitrite and nitrate) present in petrochemical wastewater by using fungi biological reactor (FBR). In laboratory scale, two aerobic biological reactors with fungi acting as immobilized biomass and up-flow were investigated. Good removals of ammonia, nitrite and nitrate were reached, and the best results occurred in the reactor 2 (R2), operated with HRT of 4 h and 0.5 g glucose/L. The reactor showed removals of 57% (± 25.4) for ammonia, 66% (± 40.7) for nitrite and 62% (± 29.9) for nitrate. The research findings showed that fungi biological reactors are a viable alternative for removal of inorganic nitrogen compounds in effluent from petroleum refineries.A ocorrência de compostos nitrogenados em efluentes de refinarias de petróleo com concentrações superiores aos limites legais é um problema sério e conhecido. A proposta desta pesquisa foi avaliar a remoção de nitrogênio amoniacal, nitrito e nitrato presentes em águas residuárias de indústrias petroquímicas, empregando processo biológico com fungos. Foram montados, em escala de laboratório, dois reatores biológicos aeróbios com fungos (RBF), com biomassa imobilizada e escoamento contínuo ascendente. Obtiveram-se boas remoções de amônia, nitrito e nitrato, sendo que os melhores resultados foram obtidos com o reator 2 (R2), operado com TDH de 4h e 0,5g de glicose/L, o qual apresentou eficiência de remoção de amônia de 57% (± 25,4), nitrito 66% (± 40,7) e nitrato 62% (± 29,9). Pelos resultados obtidos, concluiu-se que reatores biológicos com fungos são uma alternativa viável para remoção de nitrogênio amoniacal, nitrito e nitrato de efluentes de refinarias de petróleo