Browsing by Author "Pintado, Manuela M. E."
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- Bacteria immobilsation on hydroxyapatite surface for wastewater treatmentPublication . Pereira, Sofia Isabel Almeida; Piccirillo, Clara; Marques, Ana P. G. C.; Pullar, Robbert C.; Pintado, Manuela M. E.; Castro, Paula M. L.Heavy metals pollution in the environment is a big cause of concern, due to the toxicity of the metals themselves. In this work we propose an innovative method for heavy metals removal from contaminated waste water – a combination of hydroxyapatite (already used for water treatment) and microorganisms. Selected bacterial strains were immobilised on the surface of hydroxyapatite of natural origin (extracted from cod fish bones). These systems were used to tested on heavy metals, such as zinc and cadmium, from water solutions. The three strains used were Pseudomonas fluorescens, Microbacterium oxydans and Cupravidus sp.; they were selected as they showed high heavy metal resistance. SEM micrographies were used to study their immobilization on the hydroxyapatite surface. Solutions containing different concentrations of either Zn (II), Cd (II) or both metals at the same time were used. Results showed that the combination of hydroxyapatite and bacteria increases the metal uptake, indicating a synergistic action between the solid support and the bacteria biofilm. Particularly high removal rates were observed for higher heavy metal concentrations and for the Pseudomonas fluorescens strain. This work shows a promising way for environmental remediation, combining products of natural origin with microbiology.
- In vitro evaluation of “horchata” co-products as carbon source for probiotic bacteria growthPublication . Sánchez-Zapata, Elena; Fernández-López, Juana; Pérez-Alvarez, José A.; Soares, José; Sousa, Sérgio; Gomes, Ana M. P.; Pintado, Manuela M. E.Tiger nut milk ("horchata") liquid co-products (TNLC) were evaluated as carbon source for probiotic bacteria (Lactobacillus acidophilus and Bifidobacterium animalis) growth by screening via microplate assay and determination of viable cells and metabolic activity. Based on MRS five different basal media were prepared ((i) without carbon source, (ii) with 2% (w/v) glucose, (iii) with 2% (w/v) FOS, (iv) with 2% (v/v) TNLC and (v) 3% (v/v) TNLC). Additionally, reconstituted TNLC was also used as basal medium. For determination of viable cells and metabolic activity skim milk powder was used. Glucose was found to be the best substrate to L. acidophilus grows, followed by FOS and TNLC (2% and 3%, respectively). TNLC (3%) was found to be the best substrate followed by TNLC (2%), glucose and FOS, in the promotion of growth of B. animalis. The growth of L. acidophilus and B. animalis in skim milk reconstituted TNLC + water was higher than samples inoculated in skim milk reconstituted only with water (p < 0.05). This is supported by the pH effect and by the faster organic acid production (mainly lactic acid, acetic acid, and butyric acid), confirming the property of TNLC as a carbon source for probiotic bacteria growth.
- Novel eco-friendly method to extract keratin from hairPublication . Cassoni, Ana C.; Freixo, Ricardo; Pintado, Ana I. E.; Amorim, Manuela; Pereira, Carlos D.; Madureira, Ana Raquel; Pintado, Manuela M. E.Pig slaughtering for meat production is a major worldwide industry that generates many byproducts that can cause environmental problems. Nonetheless, it is possible to have a management of these residues toward the reuse and valorization of these byproducts. One opportunity focuses on the extraction of value-added compounds such as keratin since pig hair is composed by 80% of this protein. There are some methods for keratin extraction from human hair as other sources such as wool and feathers, but they bring many problems such as pollution, time-consumption, and high costs. This work uses a commercial detergent belonging to the category of degreasers, capable of fast and efficient dissolution of pig hair, followed by a simple filtration to remove residues from skin trimmings with fat and lard. The resulting solution is submitted to an ultrafiltration process to obtain a solution with higher protein content and purity, both at laboratory scale and pilot scale-up. Use of this keratin green extraction method allows to obtain a keratin product with protein purity up to 70% with a yield extraction of about 50%, which although lower than the previous methods allow protein integrity and cleaner technology. This method allows a relevant valorization of pig hair, using for the first time a simple, cost-effective, and environmentally friendly approach.