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Araújo D, Concórdio-Reis P, Marques AC, Sevrin C, Grandfils C, Alves VD, Fortunato E, Reis MAM, Freitas F. Demonstration of the ability of the bacterial polysaccharide FucoPol to flocculate kaolin suspensions. Environ Technol 2020; 41:287-295. [PMID: 29974822 DOI: 10.1080/09593330.2018.1497710] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 07/02/2018] [Indexed: 06/08/2023]
Abstract
In this study, the flocculation properties of FucoPol, a bacterial extracellular polysaccharide, were investigated. FucoPol is a high molecular weight polymer and negatively charged due to the presence of glucuronic acid and the acyl groups succinyl and pyruvyl. High flocculation rate values (>70%) were achieved with a low bioflocculant dosage of 1 mg/L, for pH values in the range 3-5 and temperature within 15-20°C. The bioflocculant was also shown to be stable after freezing/thawing and heating up to 100°C. Given the polymer's anionic character, the size of flocs formed and their surface profile, bridging seems to be the main flocculation mechanism of FucoPol. This study demonstrated that FucoPol is a promising natural, biodegradable and biocompatible alternative to the currently used synthetic or inorganic hazardous products, with potential to be used as a novel flocculation agent in several applications, such as water treatment, food or mining. Further studies will involve evaluating the reduction of cation dosage on flocculation efficiency, as well as testing the applicability of FucoPol to flocculate different types of suspended solids, such as, for example, activated carbons, soil solids or yeast cells.
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Affiliation(s)
- Diana Araújo
- UCIBIO-REQUIMTE, Chemistry Department, Faculty of Sciences and Technology, Universidade NOVA de Lisboa, Caparica, Portugal
| | - Patrícia Concórdio-Reis
- UCIBIO-REQUIMTE, Chemistry Department, Faculty of Sciences and Technology, Universidade NOVA de Lisboa, Caparica, Portugal
| | - Ana C Marques
- i3N/CENIMAT, Department of Materials Science, Faculty of Sciences and Technology, Universidade NOVA de Lisboa and CEMOP/UNINOVA, Caparica, Portugal
| | - Chantal Sevrin
- Interfaculty Research Centre of Biomaterials (CEIB), University of Liège, Liège, Belgium
| | - Christian Grandfils
- Interfaculty Research Centre of Biomaterials (CEIB), University of Liège, Liège, Belgium
| | - Vítor D Alves
- LEAF - Linking Landscape, Environment, Agriculture and Food, Instituto Superior de Agronomia, Universidade de Lisboa, Lisboa, Portugal
| | - Elvira Fortunato
- i3N/CENIMAT, Department of Materials Science, Faculty of Sciences and Technology, Universidade NOVA de Lisboa and CEMOP/UNINOVA, Caparica, Portugal
| | - Maria A M Reis
- UCIBIO-REQUIMTE, Chemistry Department, Faculty of Sciences and Technology, Universidade NOVA de Lisboa, Caparica, Portugal
| | - Filomena Freitas
- UCIBIO-REQUIMTE, Chemistry Department, Faculty of Sciences and Technology, Universidade NOVA de Lisboa, Caparica, Portugal
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Marques R, von Stosch M, Portela RMC, Torres CAV, Antunes S, Freitas F, Reis MAM, Oliveira R. Hybrid modeling of microbial exopolysaccharide (EPS) production: The case of Enterobacter A47. J Biotechnol 2017; 246:61-70. [PMID: 28153767 DOI: 10.1016/j.jbiotec.2017.01.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 01/13/2017] [Accepted: 01/27/2017] [Indexed: 11/25/2022]
Abstract
Enterobacter A47 is a bacterium that produces high amounts of a fucose-rich exopolysaccharide (EPS) from glycerol residue of the biodiesel industry. The fed-batch process is characterized by complex non-linear dynamics with highly viscous pseudo-plastic rheology due to the accumulation of EPS in the culture medium. In this paper, we study hybrid modeling as a methodology to increase the predictive power of models for EPS production optimization. We compare six hybrid structures that explore different levels of knowledge-based and machine-learning model components. Knowledge-based components consist of macroscopic material balances, Monod type kinetics, cardinal temperature and pH (CTP) dependency and power-law viscosity models. Unknown dependencies are set to be identified by a feedforward artificial neural network (ANN). A semiparametric identification schema is applied resorting to a data set of 13 independent fed-batch experiments. A parsimonious hybrid model was identified that describes the dynamics of the 13 experiments with the same parameterization. The final model is specific to Enterobacter A47 but can be easily extended to other microbial EPS processes.
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Affiliation(s)
- Rodolfo Marques
- LAQV-REQUIMTE, Systems Biology and Engineering Group, Chemistry Department, FCT/Universidade Nova de Lisboa, 2829-516 Campus Caparica, Portugal
| | - Moritz von Stosch
- LAQV-REQUIMTE, Systems Biology and Engineering Group, Chemistry Department, FCT/Universidade Nova de Lisboa, 2829-516 Campus Caparica, Portugal
| | - Rui M C Portela
- LAQV-REQUIMTE, Systems Biology and Engineering Group, Chemistry Department, FCT/Universidade Nova de Lisboa, 2829-516 Campus Caparica, Portugal
| | - Cristiana A V Torres
- UCIBIO-REQUIMTE, Biochemical Engineering Group, Chemistry Department, FCT/Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
| | - Sílvia Antunes
- UCIBIO-REQUIMTE, Biochemical Engineering Group, Chemistry Department, FCT/Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
| | - Filomena Freitas
- UCIBIO-REQUIMTE, Biochemical Engineering Group, Chemistry Department, FCT/Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
| | - Maria A M Reis
- UCIBIO-REQUIMTE, Biochemical Engineering Group, Chemistry Department, FCT/Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
| | - Rui Oliveira
- LAQV-REQUIMTE, Systems Biology and Engineering Group, Chemistry Department, FCT/Universidade Nova de Lisboa, 2829-516 Campus Caparica, Portugal.
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