Publicação: Solubilização do fosfato de rocha por Aspergillus niger
Carregando...
Tipo do documento
Data
Direito de acesso
Coleções
Área do conhecimento
CNPQ::ENGENHARIAS::ENGENHARIA QUIMICA
Título da Revista
ISSN da Revista
Título de Volume
Autores
Orientador
Coorientador
Juliatti, Fernando César
Resumo
Phosphorus (P) is an essential macro element for maintenance of life of animals and plants. It
is found in nature in the form of numerous minerals, such as apatite. The mining industry
performs the extraction and processing of phosphate reserves. In the industrial process of this
element considerable losses occur through industrial waste or through leaching by rain. The
phosphorus dragged by rain can cause the reduction of oxigen of water bodies
(eutrophication), necessary for maintaining life. Another industrial aspect concerns the
production of fertilizers which traditionally utilize strong inorganic acids (sulfuric acid) for
the obtaining of more soluble forms of phosphate, generating impactful byproducts to the
environment. Within this context, this work proposed a possible alternative for the treatment
of waste and for the traditional chemical processing, sulfuric route, by the use of Aspergillus
niger, which excretes organic acid (less impactful) that by chelation mechanisms and ion
exchange reactions, markedly increase the concentration of phosphorus in solution. Initially
the fungus A. niger was found from soybean seeds removed from the field. 12 isolated fungi
were obtained and designated numerically from 1 to 12 respectively, which were submitted to
quantitative classification. In this step the two isolated fungi with the highest power of
solubilization in a liquid form were selected, which are Isolated 7 (440 mg/L) and Isolated 9
(460mg/L), using the statistical methods Anova, Tukey and Scott-Knott in the quantitative
classification. These solubilizattion values corresponded to ± 12% of P2O5 solubilization of
phosphate rock. The next step was the experimental planning, more specifically, a Central
Compound Rotational Delineation (CCRD). The relevant variables evaluated were the
temperature in °C, substrate (glucose) in g/L and phosphate rock in g/L. As results were
obtained for the two isolated fungi selected, the equations of the static models and graphics
which represent the response surfaces between the variables. The Isolated 7 showed welldefined
optimal points that were confirmed in the validation of the model, namely, 37°C for
temperature, 41 g/L for the substrate and 36 g/L for the phosphate rock. The Isolated 9 didn´t
show optimal points, but it showed an optimal region,namely, and 25 to 31 ° C for
temperature, 28 to 37 g/L for the substrate and indifferent to phosphate rock, since this last is
not shown to be significant in the experimental range. Even at this stage, it was verified the
percentage of solubilization, ranging from 8 to 62% of P2O5 of the rock. After the planning it
was measured the variation in the initial concentration of spores in the trials at concentrations
of 105, 106, 107 and 108 spores per mL, and there was no statistical significance in the results
at the end of the experiment for both fungi. It was also performed kinetic solubilization of the
phosphorus, namely, to Isolated 7, the settling time has occurred within ± 36 days (5 weeks)
after the start of the tests, reaching the value of 632 mg/L of P in solution. The solubilization
rate was increased in the first 11 days. The settling time for the Isolated 9 occurred in ± 45
days (6 weeks), attaining the value of P in solution of 436 mg/L. The solubilization rate was
increasing in the first 7 days. Finally, it was proposed a 6 L discontinuous bioreactor with
aeration and recycle, which operated within optimum conditions defined above. It was
obtained at the final test the value of 123 mg/L of soluble Phosphorus.
Abstract
Phosphorus (P) is an essential macro element for maintenance of life of animals and plants. It
is found in nature in the form of numerous minerals, such as apatite. The mining industry
performs the extraction and processing of phosphate reserves. In the industrial process of this
element considerable losses occur through industrial waste or through leaching by rain. The
phosphorus dragged by rain can cause the reduction of oxigen of water bodies
(eutrophication), necessary for maintaining life. Another industrial aspect concerns the
production of fertilizers which traditionally utilize strong inorganic acids (sulfuric acid) for
the obtaining of more soluble forms of phosphate, generating impactful byproducts to the
environment. Within this context, this work proposed a possible alternative for the treatment
of waste and for the traditional chemical processing, sulfuric route, by the use of Aspergillus
niger, which excretes organic acid (less impactful) that by chelation mechanisms and ion
exchange reactions, markedly increase the concentration of phosphorus in solution. Initially
the fungus A. niger was found from soybean seeds removed from the field. 12 isolated fungi
were obtained and designated numerically from 1 to 12 respectively, which were submitted to
quantitative classification. In this step the two isolated fungi with the highest power of
solubilization in a liquid form were selected, which are Isolated 7 (440 mg/L) and Isolated 9
(460mg/L), using the statistical methods Anova, Tukey and Scott-Knott in the quantitative
classification. These solubilizattion values corresponded to ± 12% of P2O5 solubilization of
phosphate rock. The next step was the experimental planning, more specifically, a Central
Compound Rotational Delineation (CCRD). The relevant variables evaluated were the
temperature in °C, substrate (glucose) in g/L and phosphate rock in g/L. As results were
obtained for the two isolated fungi selected, the equations of the static models and graphics
which represent the response surfaces between the variables. The Isolated 7 showed welldefined
optimal points that were confirmed in the validation of the model, namely, 37°C for
temperature, 41 g/L for the substrate and 36 g/L for the phosphate rock. The Isolated 9 didn´t
show optimal points, but it showed an optimal region,namely, and 25 to 31 ° C for
temperature, 28 to 37 g/L for the substrate and indifferent to phosphate rock, since this last is
not shown to be significant in the experimental range. Even at this stage, it was verified the
percentage of solubilization, ranging from 8 to 62% of P2O5 of the rock. After the planning it
was measured the variation in the initial concentration of spores in the trials at concentrations
of 105, 106, 107 and 108 spores per mL, and there was no statistical significance in the results
at the end of the experiment for both fungi. It was also performed kinetic solubilization of the
phosphorus, namely, to Isolated 7, the settling time has occurred within ± 36 days (5 weeks)
after the start of the tests, reaching the value of 632 mg/L of P in solution. The solubilization
rate was increased in the first 11 days. The settling time for the Isolated 9 occurred in ± 45
days (6 weeks), attaining the value of P in solution of 436 mg/L. The solubilization rate was
increasing in the first 7 days. Finally, it was proposed a 6 L discontinuous bioreactor with
aeration and recycle, which operated within optimum conditions defined above. It was
obtained at the final test the value of 123 mg/L of soluble Phosphorus.
Palavras-chave
Aspergillus niger, Fosfato - Solubilidade, Fostatos, Solubilidade
Citação
ALVES, Glaicon Florisbelo. Solubilização do fosfato de rocha por Aspergillus niger. 2012. 146 f. Dissertação (Mestrado em Engenharias) - Universidade Federal de Uberlândia, Uberlândia, 2012. DOI https://doi.org/10.14393/ufu.di.2012.340