Susana Rodrı́guez Couto
University of Vigo
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Featured researches published by Susana Rodrı́guez Couto.
Process Biochemistry | 2002
Susana Rodrı́guez Couto; Marı́a Gundı́n; Miriam Lorenzo; M. Ángeles Sanromán
Abstract The production of laccase by Trametes versicolor under semi-solid-state conditions has been studied. Several supports (polyurethane foam, wheat straw, barley straw, wood shavings and barley bran) have been tested in order to determine the most suitable for laccase production by the above-mentioned microorganism. Barley bran led to the highest activity levels, reaching maximum values of about 1200 U/l. In this stage of research, several factors affecting laccase production (veratryl alcohol, xylidine, fresh support and the initial C/N ratio) were investigated. Xylidine was shown to be the best inducer of laccase activity, attaining values of about 1700 U/l. Moreover, the addition of fresh support not only prolonged culture lifetime but also enhanced activity levels, reaching in all the cases values higher than 2000 U/l. In addition, the decolourisation of three structurally different dyes by cultures grown on the best operating conditions determined in the present study, was monitored in order to assess the degrading capability of the ligninolytic complex secreted by such cultures. The decolourisation of all the dyes tested was almost total (85–96%) after 6 days of incubation.
Process Biochemistry | 2001
Alberto Domínguez; Isabel Rivela; Susana Rodrı́guez Couto; Ma Ángeles Sanromán
The production of ligninolytic enzymes by the white-rot fungus Phanerochaete chrysosporium BKM-F-1767 was studied in a new bioreactor configuration based on a standard rotating drum bioreactor. P. chrysosporium was grown on cubes of nylon sponge, and cultivation was carried out in batch. Two aeration levels: 0.5 and 1 vvm were tested. The latter led to activities about 3-fold higher than the former, achieving maximum manganese-dependent peroxidase (MnP) and lignin peroxidase (LiP) activities of 1350 and 364 U/l, respectively. Moreover, laccase activity was also detected, showing a highest activity of 56 U/l. In addition, the in vitro decolorisation of a model dye (Poly R-478) by the extracellular liquid obtained in the bioreactor was monitored in order to assess its ligninolytic ability. A percentage of Poly R-478 decolorisation of about 19% was achieved, after 15 min of dye incubation.
Process Biochemistry | 2002
Susana Rodrı́guez Couto; María Sandra Fragueiro Barreiro; Isabel Rivela; M.A. Longo; A. Sanromán
The production of ligninolytic enzymes by the white-rot fungus Phanerochaete chrysosporium BKM-F-1767 in a solid-state immersion bioreactor, employing cubes of nylon sponge as a support, was studied. Cultivation was carried out in both batch and continuous mode, and the effect of some operational variables (aeration level, pH) was investigated. Batch operation at an aeration level of 0.5 vvm led to maximum manganese-dependent peroxidase (MnP) and lignin peroxidase (LiP) activities of 574 and 116 U l−1, respectively. The results were compared with those obtained at a higher aeration level (1 vvm), reported in a previous work, and it appeared that LiP productivity increased with aeration rate, while MnP was not significantly affected. Continuous operation showed much lower MnP activities (around 60 U l−1) and similar LiP activities (about 132 U l−1). However, in terms of productivity the difference between batch and continuous operation for MnP was less remarkable (239 and 150 U day−1, respectively), whereas LiP productivity was ten-fold higher in continuous operation than in batch mode. This could be attributed to the influence of operation pH on ligninolytic enzyme activities. The study of the kinetic characteristics of the biocatalysts supported this hypothesis.
Biodegradation | 1998
Susana Rodrı́guez Couto; Marjaana Rättö
An inert carrier (nylon sponge), a non-inert carrier (barley straw) and the addition of veratryl alcohol or manganese (IV) oxide to the cultures were used to study the production of ligninolytic enzymes by Phanerochaete chrysosporium BKM-F-1767 (ATCC 24725) during semi solid state fermentation conditions. By supplementing the medium with these compounds we could stimulate the ligninolytic system of this fungus. The different carriers employed and the effect of adding veratryl alcohol or manganese (IV) oxide to the cultures were compared in order to determine the best system to produce high activities of ligninolytic enzymes. Lignin peroxidase (LiP) activities higher than 500 U/L and manganese-dependent peroxidase (MnP) activities about 1100 U/L were achieved.
Journal of Chemical Technology & Biotechnology | 2001
Susana Rodrı́guez Couto; Isabel Rivela; A. Sanromán
The production of ligninolytic enzymes by Phanerochaete chrysosporium BKM-F-1767 (ATCC 24725) in laboratory-scale bioreactors was studied. The cultivations were carried out in semi-solid-state conditions, employing corncob as carrier, which functioned both as a place of attachment and as a source of nutrients. Several bioreactor configurations were investigated in order to determine the most suitable one for ligninolytic enzyme production: a 1-dm3-static-bed bioreactor, a 1-dm3-static-bed bioreactor with air diffusers into the bed, a 0.5-dm3-static-bed bioreactor with air diffusers into the bed and a tray bioreactor. Although the static-bed configurations produced maximum individual lignin peroxidase (LiP) activities about 400 U dm−3 (1.0-dm3 bioreactor) and about 700 U dm−3 (0.5-dm3 bioreactor), manganese-dependent peroxidase (MnP) was not detected throughout the cultures. Nevertheless, the tray configuration led to maximum individual MnP and LiP activities of about 200 U dm−3 and 300 U dm−3, respectively. Therefore, this configuration is the most adequate of the different bioreactor configurations tested in the present work, since the ligninolytic complex formed by MnP and LiP is more efficient for its application to bio-processing systems. In addition, the results indicated the influence of the oxygen in ligninolytic enzyme production. © 2001 Society of Chemical Industry
Process Biochemistry | 2001
Susana Rodrı́guez Couto; Marjaana Rättö; Alberto Domínguez; A. Sanromán
Abstract The production of ligninolytic enzymes by Phanerochaete chrysosporium BKM-F-1767 (ATCC 24725) was studied in laboratory-scale bioreactors, operating under semi-solid-state conditions. The bioreactors were filled with inert support (polypropylene sponges) and cultivation was carried out in batch. Veratryl alcohol (2 mM) and Tween 80 (0.05% v/v) were added at the beginning of the fermentation to stimulate the production of ligninolytic enzymes. A modification in the design of a bioreactor, which operates in semi-solid-state conditions, lead to a significant improvement in the ligninolytic enzyme activities obtained. Thus, by modifying the design of the bioreactor employed in the current study, it was possible to increase about tenfold manganese-dependent peroxidase (MnP) activities and around 40% lignin peroxidase (LiP) activities. Moreover, both MnP and LiP profiles were more regular in the modified bioreactor.
Journal of Food Engineering | 2006
Susana Rodrı́guez Couto; Ma Ángeles Sanromán
Journal of Food Engineering | 2005
J. Gómez; Marta Pazos; Susana Rodrı́guez Couto; Ma Ángeles Sanromán
Process Biochemistry | 2003
Gonzalo Rancaño; Miriam Lorenzo; Norma Molares; Susana Rodrı́guez Couto; Ma̱ Ángeles Sanromán
World Journal of Microbiology & Biotechnology | 2005
Alberto Domínguez; Susana Rodrı́guez Couto; Ma Ángeles Sanromán