The Experts below are selected from a list of 13410 Experts worldwide ranked by ideXlab platform
Chandralata Raghukumar - One of the best experts on this subject based on the ideXlab platform.
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simultaneous detoxification and decolorization of molasses spent wash by the immobilized white rot fungus flavodon flavus isolated from a Marine Habitat
Enzyme and Microbial Technology, 2004Co-Authors: Chandralata Raghukumar, C Mohandass, Shilpa Kamat, M S ShailajaAbstract:The wastewaters of molasses-based alcohol distilleries contain brown colored melanoidin pigments that are one of the major pollutants. We reported decolorization of such intensely brown colored molasses spent wash (MSW) by Flavodon flavus, a white-rot basidiomycete fungus isolated from a Marine Habitat. We have further attempted to improve the process of decolorization of MSW by this fungus by immobilization. Polyurethane foam-immobilized-fungus decolorized 10% diluted MSW by 60 and 73% by days 5 and 7, respectively. The immobilized fungus could be effectively used for a minimum of three cycles repeatedly to decolorize MSW. Besides decolorization, the fungus also removed the toxicity of MSW. Toxicity bioassay of the fungus-treated molasses spent wash using an estuarine fish Oreochromis mossambicus showed no liver damage in contrast to untreated effluent, which showed moderate liver damage. We detected benzo(a)pyrene, a polycyclic aromatic hydrocarbon (PAH) in the MSW and this appears to be one of the causes of toxicity of the MSW. The concentration of PAH in the MSW decreased by 68% by day 5 on treatment with the fungus. This is the first report where decolorization of MSW is accompanied by simultaneous detoxification and decrease in PAH content of the MSW. A comparison of gel filtration chromatography of MSW, before and after treatment with the immobilized F. flavus showed disappearance of the most of the colored fractions in the fungus-treated MSW. A possible mechanism of decolorization of MSW is via the action of glucose oxidase accompanied by production of hydrogen peroxide that may ultimately act as a bleaching agent.
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decolorization of molasses spent wash by the white rot fungus flavodon flavus isolated from a Marine Habitat
Applied Microbiology and Biotechnology, 2001Co-Authors: Chandralata Raghukumar, Gauri RivonkarAbstract:Flavodon flavus (Klotzsch) Ryvarden, a basidiomycete (NIOCC strain 312) isolated from decomposing leaves of a sea grass, decolorized pigments in molasses spent wash (MSW) by 80% after 8 days of incubation, when used at concentrations of 10% and 50%. Decolorizing activity was also present in media prepared with half-strength seawater (equivalent to 15 ppt salinity). Decolorizing activity was seen in low-nitrogen medium, nutrient-rich medium and in sugarcane bagasse medium. The percentage decolorization of MSW was highest when glucose or sucrose was used as the carbon source in the low-nitrogen medium. The production of lignin-modifying enzymes, manganese-dependent peroxidase (MNP) and laccase decreased in a medium containing MSW. MNP production and MSW decolorization were inversely correlated, suggesting no role for MNP in MSW decolorization. The decolorization of MSW was not effective when F. flavus was immobilized in calcium alginate beads. Decolorization was achieved best in oxygenated cultures. Besides color, total phenolics and chemical oxygen demand were reduced by 50% in MSW treated with F. flavus, suggesting its potential in the bioremediation of effluents.
M S Shailaja - One of the best experts on this subject based on the ideXlab platform.
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simultaneous detoxification and decolorization of molasses spent wash by the immobilized white rot fungus flavodon flavus isolated from a Marine Habitat
Enzyme and Microbial Technology, 2004Co-Authors: Chandralata Raghukumar, C Mohandass, Shilpa Kamat, M S ShailajaAbstract:The wastewaters of molasses-based alcohol distilleries contain brown colored melanoidin pigments that are one of the major pollutants. We reported decolorization of such intensely brown colored molasses spent wash (MSW) by Flavodon flavus, a white-rot basidiomycete fungus isolated from a Marine Habitat. We have further attempted to improve the process of decolorization of MSW by this fungus by immobilization. Polyurethane foam-immobilized-fungus decolorized 10% diluted MSW by 60 and 73% by days 5 and 7, respectively. The immobilized fungus could be effectively used for a minimum of three cycles repeatedly to decolorize MSW. Besides decolorization, the fungus also removed the toxicity of MSW. Toxicity bioassay of the fungus-treated molasses spent wash using an estuarine fish Oreochromis mossambicus showed no liver damage in contrast to untreated effluent, which showed moderate liver damage. We detected benzo(a)pyrene, a polycyclic aromatic hydrocarbon (PAH) in the MSW and this appears to be one of the causes of toxicity of the MSW. The concentration of PAH in the MSW decreased by 68% by day 5 on treatment with the fungus. This is the first report where decolorization of MSW is accompanied by simultaneous detoxification and decrease in PAH content of the MSW. A comparison of gel filtration chromatography of MSW, before and after treatment with the immobilized F. flavus showed disappearance of the most of the colored fractions in the fungus-treated MSW. A possible mechanism of decolorization of MSW is via the action of glucose oxidase accompanied by production of hydrogen peroxide that may ultimately act as a bleaching agent.
Gauri Rivonkar - One of the best experts on this subject based on the ideXlab platform.
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decolorization of molasses spent wash by the white rot fungus flavodon flavus isolated from a Marine Habitat
Applied Microbiology and Biotechnology, 2001Co-Authors: Chandralata Raghukumar, Gauri RivonkarAbstract:Flavodon flavus (Klotzsch) Ryvarden, a basidiomycete (NIOCC strain 312) isolated from decomposing leaves of a sea grass, decolorized pigments in molasses spent wash (MSW) by 80% after 8 days of incubation, when used at concentrations of 10% and 50%. Decolorizing activity was also present in media prepared with half-strength seawater (equivalent to 15 ppt salinity). Decolorizing activity was seen in low-nitrogen medium, nutrient-rich medium and in sugarcane bagasse medium. The percentage decolorization of MSW was highest when glucose or sucrose was used as the carbon source in the low-nitrogen medium. The production of lignin-modifying enzymes, manganese-dependent peroxidase (MNP) and laccase decreased in a medium containing MSW. MNP production and MSW decolorization were inversely correlated, suggesting no role for MNP in MSW decolorization. The decolorization of MSW was not effective when F. flavus was immobilized in calcium alginate beads. Decolorization was achieved best in oxygenated cultures. Besides color, total phenolics and chemical oxygen demand were reduced by 50% in MSW treated with F. flavus, suggesting its potential in the bioremediation of effluents.
Edgar A Martinezgarcia - One of the best experts on this subject based on the ideXlab platform.
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vision based reactive autonomous navigation with obstacle avoidance towards a non invasive and cautious exploration of Marine Habitat
International Conference on Robotics and Automation, 2014Co-Authors: Geovani F Rodriguezteiles, Ricardo Perezalcocer, Alejandro Maldonadoramirez, Abril L Torresmendez, Edgar A MartinezgarciaAbstract:We present a visual based approach for reactive autonomous navigation of an underwater vehicle. In particular, we are interested in the exploration and continuous monitoring of coral reefs in order to diagnose disease or physical damage. An autonomous underwater vehicle needs to decide in real time the best route while avoiding collisions with fragile Marine life and structure. We have opted to use only visual information as input. We have improved the Simple Linear Iterative Cluster algorithm which, together with a simple nearest neighbor classifier, robustly segment and classify objects from water in a fast and efficient way, even in poor visibility conditions. From the resulting classification and the current robot's direction and orientation, the next possible free-collision route can be estimated. This is achieved by grouping together neighboring water superpixels (considered as "regions of interest"). Finally, we use a model-free robust control scheme that allows the robot to autonomously navigate through the free-collision routes obtained in the first step. The experimental results, both in simulations and in practice, show the effectiveness of the proposed navigation system. In this paper, an autonomous reactive navigation approach based on visual information for an underwater vehicle is presented. Our method is divided in two stages. In the first stage, we use our improved version of the Simple Linear Iterative Clustering (SLIC) superpixel algorithm (4) to robustly segment low-resolution images based on their color features. We exploit the fact that high-resolution information is not needed for navigation (see (5), (6) for studies on the subject) and also that for underwater images, the CIELab color space can be adjusted to highlight only the color on objects that do not represent water itself. Given that this algorithm has a linear computational complexity, the objects and RoI (water) can be segmented in a fast and efficient way. After this, a simple nearest neighbor classifier is applied to separate and detect objects from water. In the second stage, from the resulted classification and the current direction and orientation of the robot, the next possible free-collision route (also called direction of escape) can be estimated. This is achieved by obtaining the geometric center of the area covered by a RoI. We have previously used this approach for indoor mobile robot navigation with promising results (7). Finally, we present a model-free robust control scheme that allows the robot to autonomously navigate by mapping the image error (in terms of the geometric center of RoI) to robot motion directly. The experimental results show the effectiveness of the proposed navigation system.
Edgar A. Martínez-garcía - One of the best experts on this subject based on the ideXlab platform.
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Vision-based reactive autonomous navigation with obstacle avoidance: Towards a non-invasive and cautious exploration of Marine Habitat
2014 IEEE International Conference on Robotics and Automation (ICRA), 2014Co-Authors: Geovani F. Rodríguez-teiles, Ricardo Pérez-alcocer, Alejandro Maldonado-ramírez, Abril L. Torres-méndez, Bir Bikram Dey, Edgar A. Martínez-garcíaAbstract:We present a visual based approach for reactive autonomous navigation of an underwater vehicle. In particular, we are interested in the exploration and continuous monitoring of coral reefs in order to diagnose disease or physical damage. An autonomous underwater vehicle needs to decide in real time the best route while avoiding collisions with fragile Marine life and structure. We have opted to use only visual information as input. We have improved the Simple Linear Iterative Cluster algorithm which, together with a simple nearest neighbor classifier, robustly segment and classify objects from water in a fast and efficient way, even in poor visibility conditions. From the resulting classification and the current robot's direction and orientation, the next possible free-collision route can be estimated. This is achieved by grouping together neighboring water superpixels (considered as “regions of interest”). Finally, we use a model-free robust control scheme that allows the robot to autonomously navigate through the free-collision routes obtained in the first step. The experimental results, both in simulations and in practice, show the effectiveness of the proposed navigation system.