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Papers by ROSANGELA BUZON PIROTA

Research paper thumbnail of Enzymatic Hydrolysis of Sugarcane Bagasse Using Enzyme Extract and Whole Solid-state Fermentation Medium of Two Newly Isolated Strains of Aspergillus Oryzae

Chemical Engineering Transactions, 2014

Enzymatic conversion of lignocellulosic biomass into fuels and chemicals will be a key technology... more Enzymatic conversion of lignocellulosic biomass into fuels and chemicals will be a key technology in the future. However, in order to make this process economically feasible, it is necessary to improve the efficiency of enzyme production, since the cost of the enzymatic cocktails significantly influences the viability of the overall process. In this sense, the use of solid-state fermentation (SSF) is particularly advantageous for enzyme production. Here, a comparative study on the enzymatic hydrolysis of steam- exploded sugarcane bagasse (SESB) using enzymatic extract (EE) and whole solid-state fermentation medium (WM) of two newly isolated strains of Aspergillus oryzae (P6B2 and P27C3A) from the Amazon Rainforest was carried out. The biomass conversion using WM from A. oryzae P6B2 was more efficient when compared with the EE, while for A. oryzae P27C3A the conversion yields were similar. The WM from P27C3A supplemented with a low dosage of commercial enzyme resulted in a final conv...

Research paper thumbnail of Sistema automatizado para processos de fermentação em estado sólido: produção de enzimas pelo fungo trichoderma harzianum

Research paper thumbnail of Modelagem matemática do processo de fermentação em estado sólido com aspergilius niger para produção de celulases

Research paper thumbnail of BIOPROCESS DEVELOPMENTS FOR CELLULASE PRODUCTION BY Aspergillus oryzae CULTIVATED UNDER SOLID-STATE FERMENTATION

Brazilian Journal of Chemical Engineering, 2016

Research paper thumbnail of Caracterização de fungos isolados da Floresta Amazônica quanto à produção de xilanases pelos processos de fermentação em estado sólido e fermentação submersa

Research paper thumbnail of Simplification of the Biomass to Ethanol Conversion Process by Using the Whole Medium of Filamentous Fungi Cultivated Under Solid-State Fermentation

BioEnergy Research, 2014

ABSTRACT A novel simplified configuration is proposed for the conversion of biomass to ethanol us... more ABSTRACT A novel simplified configuration is proposed for the conversion of biomass to ethanol using whole medium enzymatic cocktails (WM) and enzymatic extracts (EE) from different filamentous fungi (Trichoderma reesei, Aspergillus niger, and Aspergillus oryzae) cultivated under solid-state fermentation (SSF) for the hydrolysis of steam-exploded sugarcane bagasse (SESB). The hydrolyzed material derived from the saccharification of SESB using the combinations A. niger WM + T. reesei EE, A. oryzae WM + A. niger EE, and A. niger EE + T. reesei WM resulted in the best biomass conversion yields (66, 65, and 64 % of the theoretical reducing sugar yields, respectively). The best ethanol production (84 % of the theoretical yield) was obtained using the material hydrolyzed by a combination of A. oryzae WM + A. niger EE. The enzymatic conversion of SESB using on-site produced enzymes from the whole SSF cultivation medium, followed by an ethanol production step, is a potential configuration for the biomass to ethanol conversion process. This novel simplified configuration would enable the use of a single reactor system, avoiding the need for additional separation steps.

Research paper thumbnail of Improving the extraction conditions of endoglucanase produced by Aspergillus niger under solid-state fermentation

Brazilian Journal of Chemical Engineering, 2013

Research paper thumbnail of Isolation and characterization of a β-galactosidase from a new Amazon forest strain of Aspergillus niger as a potential accessory enzyme for biomass conversion

Biocatalysis and Biotransformation, 2013

Research paper thumbnail of Isolamento de fungos visando à produção de enzimas celulolíticas para aplicação na hidrólise da biomassa

Research paper thumbnail of Effect of initial moisture content on two Amazon rainforest Aspergillus strains cultivated on agro-industrial residues: Biomass-degrading enzymes production and characterization

Industrial Crops and Products, 2013

Research paper thumbnail of Produção de enzimas despolimerizantes de materal vegetal por fungos termofílicos usando suplemento comercial como substrato

... de laboratório pela ajuda na realizaçmo deste trabalho: Andréia, Ana Flávia, Ana Lúcia, Carol... more ... de laboratório pela ajuda na realizaçmo deste trabalho: Andréia, Ana Flávia, Ana Lúcia, Carol, Caroline, Denise, Ellen, Ellen Lago, Fabiana, Gisele, Hamilton, Heloiza, Lilian, Maira, Marcelo, Marcia Moretti ... Grande parte desses resíduos fica disponível no campo tornando-se, ...

Research paper thumbnail of Simplificação do processo de conversão de biomassa a etanol usando enzimas do meio fermentado integral de fungos filamentosos cultivados por fermentação em estado sólido

Research paper thumbnail of Enhancing xylanases production by a new Amazon Forest strain of Aspergillus oryzae using solid-state fermentation under controlled operation conditions

Industrial Crops and Products, 2013

Bioprocess studies towards improving the production of xylanases are of great value due to the im... more Bioprocess studies towards improving the production of xylanases are of great value due to the importance of these enzymes on several industrial applications. This work evaluates the effects of operational conditions on xylanase production by a new strain of Aspergillus oryzae (P6B2) isolated from the Amazon Rain Forest. The fungus was cultivated under solid-state fermentation (SSF) using an instrumented lab-scale bioreactor equipped with an on-line automated monitoring and control system. The effects of initial substrate moisture content and temperature on xylanase production were evaluated and compared to static conditions. It was outstanding the positive effect on xylanase production by SSF cultivations under controlled conditions of forced over static aeration conditions. The conditions selected for further characterization resulted in the highest production of xylanase (2830.7 IU/g), which was achieved using an initial substrate moisture content of 80%, at 28 °C with an air flo...

Research paper thumbnail of Enzyme production by solid-state fermentation: Application to animal nutrition

Animal Feed Science and Technology, Jun 1, 2008

Research paper thumbnail of Using Amazon forest fungi and agricultural residues as a strategy to produce cellulolytic enzymes

Biomass and Bioenergy, Feb 1, 2012

The successful strategy to produce cellulolytic enzymes includes both microorganism selection and... more The successful strategy to produce cellulolytic enzymes includes both microorganism selection and improved fermentation process conditions. This work describes the isolation, screening and selection of biomass-degrading fungi species from the Amazon forest and ...

Research paper thumbnail of Caracterização de fungos isolados da região Amazônica quanto ao potencial para produção das enzimas envolvidas na conversão da biomassa vegetal

Research paper thumbnail of Production and evaluation of exogenous fibrolytic enzymes in presence of the rumen fluid and in vitro digestibility of tropical forage using enzymatic complex

Research paper thumbnail of Effect of initial moisture content on two Amazon rainforest Aspergillus strains cultivated on agro-industrial residues: Biomass-degrading enzymes production and characterization

Industrial Crops and Products, 2013

Research paper thumbnail of Isolation and characterization of a β-galactosidase from a new Amazon forest strain of Aspergillus niger as a potential accessory enzyme for biomass conversion

Biocatalysis and Biotransformation, 2014

The selection of enzyme-producing fungi is useful to obtain enzymes required to hydrolyze lignoce... more The selection of enzyme-producing fungi is useful to obtain enzymes required to hydrolyze lignocellulosic material and thereby contribute to biomass conversion into fuels and chemicals. Besides cellulases, the presence of accessory enzymes in enzyme cocktails is necessary to enhance hydrolysis efficiency. This study evaluates the production, purification, and biochemical-kinetic characterization of beta-galactosidase produced by a new strain of Aspergillus niger (P47C3) isolated from the Amazon Forest. The A. niger (P47C3) was cultured under SmF conditions and beta-galactosidase was purified in a three-step purification, using an ultrafiltration membrane, ion exchange (TSK-SP), and gel filtration (Sephacryl S-200). The calculated molecular weight of the purified enzyme was 125 kDa. Optimum pH (4.0) and temperature (55 degrees C) of beta-galactosidase activity were determined. The values of the kinetic parameters obtained from p-nitrophenyl-beta-D-galactopyranoside (PNPG) hydrolysis ...

Research paper thumbnail of Addendum to Issue 1 - ENZITEC 2012Simultaneous biosynthesis of biomass-degrading enzymes using co-cultivation of Aspergillus niger and Trichoderma reesei

Biocatalysis and Biotransformation, 2014

Abstract The biotransformation of lignocellulosic materials into biofuels and chemicals requires ... more Abstract The biotransformation of lignocellulosic materials into biofuels and chemicals requires the simultaneous action of multiple enzymes. Since the cost of producing an efficient enzyme system maybe high, mixed cultures of microorganisms maybe an alternative to increase enzymatic production and consequently reduce costs. This study investigated the effects of different inoculum ratios and inoculation delays on the biosynthesis of cellulases and xylanases during co-cultivation of Aspergillus niger and Trichoderma reesei under solid-state fermentation (SSF). While the monoculture of T. reesei was more efficient for CMCase production than the co-cultivation of A. niger and T. reesei, a significant increase in β-glucosidase and xylanase production was achieved by co-cultivation of both species. The maximum CMCase activity of 153.91 IU/g was obtained with T. reesei after 48 h of cultivation, while the highest β-glucosidase activity of 119.71 IU/g (after 120 h) was obtained by co-cultivation of A. niger and T. reesei with a 3:1 inoculum ratio (A. niger: T. reesei). The greatest xylanase activity observed was 589.39 IU/g after 72 h of mixed culturing of A. niger and T. Reesei with a 1:1 inoculum ratio. This is the first study where the effects of inoculum ratio and inoculation delay in mixed culture of T. reesei and A. niger under SSF have been systematically assessed, and it indicates co-cultivation as a feasible alternative to increase enzymatic production.

Research paper thumbnail of Enzymatic Hydrolysis of Sugarcane Bagasse Using Enzyme Extract and Whole Solid-state Fermentation Medium of Two Newly Isolated Strains of Aspergillus Oryzae

Chemical Engineering Transactions, 2014

Enzymatic conversion of lignocellulosic biomass into fuels and chemicals will be a key technology... more Enzymatic conversion of lignocellulosic biomass into fuels and chemicals will be a key technology in the future. However, in order to make this process economically feasible, it is necessary to improve the efficiency of enzyme production, since the cost of the enzymatic cocktails significantly influences the viability of the overall process. In this sense, the use of solid-state fermentation (SSF) is particularly advantageous for enzyme production. Here, a comparative study on the enzymatic hydrolysis of steam- exploded sugarcane bagasse (SESB) using enzymatic extract (EE) and whole solid-state fermentation medium (WM) of two newly isolated strains of Aspergillus oryzae (P6B2 and P27C3A) from the Amazon Rainforest was carried out. The biomass conversion using WM from A. oryzae P6B2 was more efficient when compared with the EE, while for A. oryzae P27C3A the conversion yields were similar. The WM from P27C3A supplemented with a low dosage of commercial enzyme resulted in a final conv...

Research paper thumbnail of Sistema automatizado para processos de fermentação em estado sólido: produção de enzimas pelo fungo trichoderma harzianum

Research paper thumbnail of Modelagem matemática do processo de fermentação em estado sólido com aspergilius niger para produção de celulases

Research paper thumbnail of BIOPROCESS DEVELOPMENTS FOR CELLULASE PRODUCTION BY Aspergillus oryzae CULTIVATED UNDER SOLID-STATE FERMENTATION

Brazilian Journal of Chemical Engineering, 2016

Research paper thumbnail of Caracterização de fungos isolados da Floresta Amazônica quanto à produção de xilanases pelos processos de fermentação em estado sólido e fermentação submersa

Research paper thumbnail of Simplification of the Biomass to Ethanol Conversion Process by Using the Whole Medium of Filamentous Fungi Cultivated Under Solid-State Fermentation

BioEnergy Research, 2014

ABSTRACT A novel simplified configuration is proposed for the conversion of biomass to ethanol us... more ABSTRACT A novel simplified configuration is proposed for the conversion of biomass to ethanol using whole medium enzymatic cocktails (WM) and enzymatic extracts (EE) from different filamentous fungi (Trichoderma reesei, Aspergillus niger, and Aspergillus oryzae) cultivated under solid-state fermentation (SSF) for the hydrolysis of steam-exploded sugarcane bagasse (SESB). The hydrolyzed material derived from the saccharification of SESB using the combinations A. niger WM + T. reesei EE, A. oryzae WM + A. niger EE, and A. niger EE + T. reesei WM resulted in the best biomass conversion yields (66, 65, and 64 % of the theoretical reducing sugar yields, respectively). The best ethanol production (84 % of the theoretical yield) was obtained using the material hydrolyzed by a combination of A. oryzae WM + A. niger EE. The enzymatic conversion of SESB using on-site produced enzymes from the whole SSF cultivation medium, followed by an ethanol production step, is a potential configuration for the biomass to ethanol conversion process. This novel simplified configuration would enable the use of a single reactor system, avoiding the need for additional separation steps.

Research paper thumbnail of Improving the extraction conditions of endoglucanase produced by Aspergillus niger under solid-state fermentation

Brazilian Journal of Chemical Engineering, 2013

Research paper thumbnail of Isolation and characterization of a β-galactosidase from a new Amazon forest strain of Aspergillus niger as a potential accessory enzyme for biomass conversion

Biocatalysis and Biotransformation, 2013

Research paper thumbnail of Isolamento de fungos visando à produção de enzimas celulolíticas para aplicação na hidrólise da biomassa

Research paper thumbnail of Effect of initial moisture content on two Amazon rainforest Aspergillus strains cultivated on agro-industrial residues: Biomass-degrading enzymes production and characterization

Industrial Crops and Products, 2013

Research paper thumbnail of Produção de enzimas despolimerizantes de materal vegetal por fungos termofílicos usando suplemento comercial como substrato

... de laboratório pela ajuda na realizaçmo deste trabalho: Andréia, Ana Flávia, Ana Lúcia, Carol... more ... de laboratório pela ajuda na realizaçmo deste trabalho: Andréia, Ana Flávia, Ana Lúcia, Carol, Caroline, Denise, Ellen, Ellen Lago, Fabiana, Gisele, Hamilton, Heloiza, Lilian, Maira, Marcelo, Marcia Moretti ... Grande parte desses resíduos fica disponível no campo tornando-se, ...

Research paper thumbnail of Simplificação do processo de conversão de biomassa a etanol usando enzimas do meio fermentado integral de fungos filamentosos cultivados por fermentação em estado sólido

Research paper thumbnail of Enhancing xylanases production by a new Amazon Forest strain of Aspergillus oryzae using solid-state fermentation under controlled operation conditions

Industrial Crops and Products, 2013

Bioprocess studies towards improving the production of xylanases are of great value due to the im... more Bioprocess studies towards improving the production of xylanases are of great value due to the importance of these enzymes on several industrial applications. This work evaluates the effects of operational conditions on xylanase production by a new strain of Aspergillus oryzae (P6B2) isolated from the Amazon Rain Forest. The fungus was cultivated under solid-state fermentation (SSF) using an instrumented lab-scale bioreactor equipped with an on-line automated monitoring and control system. The effects of initial substrate moisture content and temperature on xylanase production were evaluated and compared to static conditions. It was outstanding the positive effect on xylanase production by SSF cultivations under controlled conditions of forced over static aeration conditions. The conditions selected for further characterization resulted in the highest production of xylanase (2830.7 IU/g), which was achieved using an initial substrate moisture content of 80%, at 28 °C with an air flo...

Research paper thumbnail of Enzyme production by solid-state fermentation: Application to animal nutrition

Animal Feed Science and Technology, Jun 1, 2008

Research paper thumbnail of Using Amazon forest fungi and agricultural residues as a strategy to produce cellulolytic enzymes

Biomass and Bioenergy, Feb 1, 2012

The successful strategy to produce cellulolytic enzymes includes both microorganism selection and... more The successful strategy to produce cellulolytic enzymes includes both microorganism selection and improved fermentation process conditions. This work describes the isolation, screening and selection of biomass-degrading fungi species from the Amazon forest and ...

Research paper thumbnail of Caracterização de fungos isolados da região Amazônica quanto ao potencial para produção das enzimas envolvidas na conversão da biomassa vegetal

Research paper thumbnail of Production and evaluation of exogenous fibrolytic enzymes in presence of the rumen fluid and in vitro digestibility of tropical forage using enzymatic complex

Research paper thumbnail of Effect of initial moisture content on two Amazon rainforest Aspergillus strains cultivated on agro-industrial residues: Biomass-degrading enzymes production and characterization

Industrial Crops and Products, 2013

Research paper thumbnail of Isolation and characterization of a β-galactosidase from a new Amazon forest strain of Aspergillus niger as a potential accessory enzyme for biomass conversion

Biocatalysis and Biotransformation, 2014

The selection of enzyme-producing fungi is useful to obtain enzymes required to hydrolyze lignoce... more The selection of enzyme-producing fungi is useful to obtain enzymes required to hydrolyze lignocellulosic material and thereby contribute to biomass conversion into fuels and chemicals. Besides cellulases, the presence of accessory enzymes in enzyme cocktails is necessary to enhance hydrolysis efficiency. This study evaluates the production, purification, and biochemical-kinetic characterization of beta-galactosidase produced by a new strain of Aspergillus niger (P47C3) isolated from the Amazon Forest. The A. niger (P47C3) was cultured under SmF conditions and beta-galactosidase was purified in a three-step purification, using an ultrafiltration membrane, ion exchange (TSK-SP), and gel filtration (Sephacryl S-200). The calculated molecular weight of the purified enzyme was 125 kDa. Optimum pH (4.0) and temperature (55 degrees C) of beta-galactosidase activity were determined. The values of the kinetic parameters obtained from p-nitrophenyl-beta-D-galactopyranoside (PNPG) hydrolysis ...

Research paper thumbnail of Addendum to Issue 1 - ENZITEC 2012Simultaneous biosynthesis of biomass-degrading enzymes using co-cultivation of Aspergillus niger and Trichoderma reesei

Biocatalysis and Biotransformation, 2014

Abstract The biotransformation of lignocellulosic materials into biofuels and chemicals requires ... more Abstract The biotransformation of lignocellulosic materials into biofuels and chemicals requires the simultaneous action of multiple enzymes. Since the cost of producing an efficient enzyme system maybe high, mixed cultures of microorganisms maybe an alternative to increase enzymatic production and consequently reduce costs. This study investigated the effects of different inoculum ratios and inoculation delays on the biosynthesis of cellulases and xylanases during co-cultivation of Aspergillus niger and Trichoderma reesei under solid-state fermentation (SSF). While the monoculture of T. reesei was more efficient for CMCase production than the co-cultivation of A. niger and T. reesei, a significant increase in β-glucosidase and xylanase production was achieved by co-cultivation of both species. The maximum CMCase activity of 153.91 IU/g was obtained with T. reesei after 48 h of cultivation, while the highest β-glucosidase activity of 119.71 IU/g (after 120 h) was obtained by co-cultivation of A. niger and T. reesei with a 3:1 inoculum ratio (A. niger: T. reesei). The greatest xylanase activity observed was 589.39 IU/g after 72 h of mixed culturing of A. niger and T. Reesei with a 1:1 inoculum ratio. This is the first study where the effects of inoculum ratio and inoculation delay in mixed culture of T. reesei and A. niger under SSF have been systematically assessed, and it indicates co-cultivation as a feasible alternative to increase enzymatic production.