Joana Pais - Academia.edu (original) (raw)
Papers by Joana Pais
New Biotechnology, Sep 1, 2009
Bioresource Technology, 2009
A new extracellular charged polysaccharide composed mainly by galactose, with lower amounts of ma... more A new extracellular charged polysaccharide composed mainly by galactose, with lower amounts of mannose, glucose and rhamnose, was produced by the cultivation of Pseudomonas oleovorans NRRL B-14682 using glycerol as the sole carbon source. Thermal and solid-state NMR analysis showed that this polymer is essentially amorphous, with a glass transition temperature of 155.7 degrees C. The exopolysaccharide aqueous solutions have viscoelastic properties similar to that of Guar gum, but with affinity to salts as a result of its polyelectrolyte character. In addition, the exopolysaccharide has demonstrated good flocculating and emulsifying properties and film-forming capacity. These properties make this polymer a good alternative to more expensive natural polysaccharides, such as Guar gum, in several applications in the food, pharmaceutical, cosmetic, textile, paper and petroleum industries.
Frontiers in Environmental Science, Sep 20, 2022
Regional Studies in Marine Science, Dec 1, 2023
bioRxiv, 2020
The biopolyester cutin is ubiquitous in land plants, building the polymeric matrix of the plant’s... more The biopolyester cutin is ubiquitous in land plants, building the polymeric matrix of the plant’s outermost defensive barrier - the cuticle. Cutin influences many biological processes in planta however due to its complexity and highly branched nature, the native structure remains partially unresolved. Our aim was to define an original workflow for the purification and systematic characterisation of the molecular structure of cutin. To purify cutin we tested the ionic liquids cholinium hexanoate and 1-butyl-3-methyl-imidazolium acetate. The ensuing polymers are highly esterified, amorphous and have the typical monomeric composition as demonstrated by solid state NMR, complemented by spectroscopic (GC-MS), thermal (DSC) and x-ray scattering (WAXS) analyses. A systematic study by solution-state NMR of cryogenically milled cutins extracted from Micro-Tom tomatoes (the wild type and the gpat6 and cus1 mutants) was undertaken. Their molecular structures, relative distribution of ester ali...
Materials Today Bio, 2020
Materials Today Bio, 2020
Applied Microbiology and Biotechnology, 2019
European Journal of Applied Microbiology, 1975
Summary First investigations of a slimy material fromP. stutzeri show that it represents a polysa... more Summary First investigations of a slimy material fromP. stutzeri show that it represents a polysaccharide, composed of glucose and mannose in nearly equal amounts and of rhamnose and another unknown sugar in lesser quantities. Acid hydrolysis of the polysaccharide additionally yields an oligomeric, very acid stable compound which could not as yet be identified.
Sustainability, 2022
The majority of microplastics (MP) found in the marine environment have land-based sources and ri... more The majority of microplastics (MP) found in the marine environment have land-based sources and rivers are known as carriers of these particles to the ocean. This work is the first to study MP in the Lis River Basin and coastal shoreline (total nine sampling sites) and the potential relationship with inputs from 105 companies/units. We report the seasonal abundance, typology, colour, size, and polymer distribution of MP in surface water and sediment. To the collected samples, a digestion protocol was applied, followed by filtration. For sediment, an MP density separation was performed prior to filtration. MP were mostly fibres (0.02 to 1111.11 items.m−3 in water and 10.66 to 1609.64 items.kg−1 in sediment) and fragments (0.02 to 2311.11 items.m−3 in water and 10.66 to 501.01 items.kg−1 in sediment). The most frequent colours were transparent and blue, and MP were mostly smaller than 1 mm in water and 2 mm in sediment samples. The most abundant polymers in water were polyethylene (37%...
Engineering in Life Sciences, 2009
An integrated procedure for the recovery of polyhydroxybutyrate (PHB) produced by Cupriavidus nec... more An integrated procedure for the recovery of polyhydroxybutyrate (PHB) produced by Cupriavidus necator based on the extraction with 1,2-propylene carbonate was eval-uated. The effect of temperature (1001451C) and contact time (1545min), preci-pitation period, and biomass ...
This invention concerns a biopolymer consisting of a polysaccharide composed of galactose (50-90%... more This invention concerns a biopolymer consisting of a polysaccharide composed of galactose (50-90%), glucose (1-25%), mannose (1-25%) and rhamnose (0.5-20%), which may additionally contain, in trace amounts, xylose, fucose, ribose, arabinose and/or fructose. The galactose-rich polymer also contains non-saccharide components, namely, acyl groups. This invention also concerns a process for the production of the galactose-rich polymer, by microbial fermentation using glycerol or glycerol-rich substrates as carbon source, and recovery of the polymer from the culture broth. From the process for the production of the galactose-rich polymer results the co-production of intracellular biopolymers, namely, polyhydroxyalkanoates. This invention also concerns to the application of the galactose-rich polymer and the products of its partial or complete degradation and/or derivatization, namely, galacto-oligosaccharides, galactose, rhamnose and others, by physical, chemical and/or biological methods, in food, agricultural, textile and paper industries, pharmaceutical and cosmetic products, oil and metal recovery in mining industry, industrial waste treatment and wastewater treatment, among others.
Process Biochemistry, 2010
Enzyme and Microbial Technology, 2014
In this work Escherichia coli strain CML3-1 was engineered through the insertion of Cupriavidus n... more In this work Escherichia coli strain CML3-1 was engineered through the insertion of Cupriavidus necator P(3HB)-synthesis genes, fused to a lactose-inducible promoter, into the chromosome, via transposition-mediated mechanism. It was shown that polyhydroxyalkanotes (PHAs) production by this strain, using cheese whey, was low due to a significant organic acids (OA) synthesis. The proton suicide method was used as a strategy to obtain an E. coli mutant strain with a reduced OA-producing capacity, aiming at driving bacterial metabolism toward PHAs synthesis. Thirteen E. coli mutant strains were obtained and tested in shake flask assays, using either rich or defined media supplemented with lactose. P8-X8 was selected as the best candidate strain for bioreactor fed-batch tests using cheese whey as the sole carbon source. Although cell growth was considerably slower for this mutant strain, a lower yield of OA on substrate (0.04 Cmol(OA)/Cmol(lac)) and a higher P(3HB) production (18.88 g(P(3HB))/L) were achieved, comparing to the original recombinant strain (0.11 Cmol(OA)/Cmol(lac) and 7.8 g(P(3HB))/L, respectively). This methodology showed to be effective on the reduction of OA yield by consequently improving the P(3HB) yield on lactose (0.28 Cmol (P(3HB))/Cmol(lac) vs 0.10 Cmol(P(3HB))/Cmol(lac) of the original strain).
New biotechnology, Jan 29, 2015
Haloferax mediterranei was cultivated in highly saline medium using cheese whey as the substrate ... more Haloferax mediterranei was cultivated in highly saline medium using cheese whey as the substrate for the production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate), P(3HB-co-3HV). Acid hydrolysis provided a simple inexpensive method to obtain a cheese whey hydrolysate that was used for cultivation of H. mediterranei. Batch bioreactor cultivation of H. mediterranei resulted in the production of an active biomass concentration of 7.54gL(-1) with a polymer content of 53%, and a volumetric productivity of 4.04gL(-1)day(-1). Supplementation of the cultivation medium with micronutrients favored galactose consumption that was used for polymer synthesis after exhaustion of the available glucose. P(3HB-co-3HV) with a 3-hydroxyvalerate content of 1.5mol% was extracted from the biomass by hypo-osmotic shock. The polymer presented a molecular mass of 4.4×10(5), with a polydispersity index of 1.5. This work demonstrated the feasibility of using cheese whey for the production of a value-added bio...
Process Biochemistry, 2010
New Biotechnology, Sep 1, 2009
Bioresource Technology, 2009
A new extracellular charged polysaccharide composed mainly by galactose, with lower amounts of ma... more A new extracellular charged polysaccharide composed mainly by galactose, with lower amounts of mannose, glucose and rhamnose, was produced by the cultivation of Pseudomonas oleovorans NRRL B-14682 using glycerol as the sole carbon source. Thermal and solid-state NMR analysis showed that this polymer is essentially amorphous, with a glass transition temperature of 155.7 degrees C. The exopolysaccharide aqueous solutions have viscoelastic properties similar to that of Guar gum, but with affinity to salts as a result of its polyelectrolyte character. In addition, the exopolysaccharide has demonstrated good flocculating and emulsifying properties and film-forming capacity. These properties make this polymer a good alternative to more expensive natural polysaccharides, such as Guar gum, in several applications in the food, pharmaceutical, cosmetic, textile, paper and petroleum industries.
Frontiers in Environmental Science, Sep 20, 2022
Regional Studies in Marine Science, Dec 1, 2023
bioRxiv, 2020
The biopolyester cutin is ubiquitous in land plants, building the polymeric matrix of the plant’s... more The biopolyester cutin is ubiquitous in land plants, building the polymeric matrix of the plant’s outermost defensive barrier - the cuticle. Cutin influences many biological processes in planta however due to its complexity and highly branched nature, the native structure remains partially unresolved. Our aim was to define an original workflow for the purification and systematic characterisation of the molecular structure of cutin. To purify cutin we tested the ionic liquids cholinium hexanoate and 1-butyl-3-methyl-imidazolium acetate. The ensuing polymers are highly esterified, amorphous and have the typical monomeric composition as demonstrated by solid state NMR, complemented by spectroscopic (GC-MS), thermal (DSC) and x-ray scattering (WAXS) analyses. A systematic study by solution-state NMR of cryogenically milled cutins extracted from Micro-Tom tomatoes (the wild type and the gpat6 and cus1 mutants) was undertaken. Their molecular structures, relative distribution of ester ali...
Materials Today Bio, 2020
Materials Today Bio, 2020
Applied Microbiology and Biotechnology, 2019
European Journal of Applied Microbiology, 1975
Summary First investigations of a slimy material fromP. stutzeri show that it represents a polysa... more Summary First investigations of a slimy material fromP. stutzeri show that it represents a polysaccharide, composed of glucose and mannose in nearly equal amounts and of rhamnose and another unknown sugar in lesser quantities. Acid hydrolysis of the polysaccharide additionally yields an oligomeric, very acid stable compound which could not as yet be identified.
Sustainability, 2022
The majority of microplastics (MP) found in the marine environment have land-based sources and ri... more The majority of microplastics (MP) found in the marine environment have land-based sources and rivers are known as carriers of these particles to the ocean. This work is the first to study MP in the Lis River Basin and coastal shoreline (total nine sampling sites) and the potential relationship with inputs from 105 companies/units. We report the seasonal abundance, typology, colour, size, and polymer distribution of MP in surface water and sediment. To the collected samples, a digestion protocol was applied, followed by filtration. For sediment, an MP density separation was performed prior to filtration. MP were mostly fibres (0.02 to 1111.11 items.m−3 in water and 10.66 to 1609.64 items.kg−1 in sediment) and fragments (0.02 to 2311.11 items.m−3 in water and 10.66 to 501.01 items.kg−1 in sediment). The most frequent colours were transparent and blue, and MP were mostly smaller than 1 mm in water and 2 mm in sediment samples. The most abundant polymers in water were polyethylene (37%...
Engineering in Life Sciences, 2009
An integrated procedure for the recovery of polyhydroxybutyrate (PHB) produced by Cupriavidus nec... more An integrated procedure for the recovery of polyhydroxybutyrate (PHB) produced by Cupriavidus necator based on the extraction with 1,2-propylene carbonate was eval-uated. The effect of temperature (1001451C) and contact time (1545min), preci-pitation period, and biomass ...
This invention concerns a biopolymer consisting of a polysaccharide composed of galactose (50-90%... more This invention concerns a biopolymer consisting of a polysaccharide composed of galactose (50-90%), glucose (1-25%), mannose (1-25%) and rhamnose (0.5-20%), which may additionally contain, in trace amounts, xylose, fucose, ribose, arabinose and/or fructose. The galactose-rich polymer also contains non-saccharide components, namely, acyl groups. This invention also concerns a process for the production of the galactose-rich polymer, by microbial fermentation using glycerol or glycerol-rich substrates as carbon source, and recovery of the polymer from the culture broth. From the process for the production of the galactose-rich polymer results the co-production of intracellular biopolymers, namely, polyhydroxyalkanoates. This invention also concerns to the application of the galactose-rich polymer and the products of its partial or complete degradation and/or derivatization, namely, galacto-oligosaccharides, galactose, rhamnose and others, by physical, chemical and/or biological methods, in food, agricultural, textile and paper industries, pharmaceutical and cosmetic products, oil and metal recovery in mining industry, industrial waste treatment and wastewater treatment, among others.
Process Biochemistry, 2010
Enzyme and Microbial Technology, 2014
In this work Escherichia coli strain CML3-1 was engineered through the insertion of Cupriavidus n... more In this work Escherichia coli strain CML3-1 was engineered through the insertion of Cupriavidus necator P(3HB)-synthesis genes, fused to a lactose-inducible promoter, into the chromosome, via transposition-mediated mechanism. It was shown that polyhydroxyalkanotes (PHAs) production by this strain, using cheese whey, was low due to a significant organic acids (OA) synthesis. The proton suicide method was used as a strategy to obtain an E. coli mutant strain with a reduced OA-producing capacity, aiming at driving bacterial metabolism toward PHAs synthesis. Thirteen E. coli mutant strains were obtained and tested in shake flask assays, using either rich or defined media supplemented with lactose. P8-X8 was selected as the best candidate strain for bioreactor fed-batch tests using cheese whey as the sole carbon source. Although cell growth was considerably slower for this mutant strain, a lower yield of OA on substrate (0.04 Cmol(OA)/Cmol(lac)) and a higher P(3HB) production (18.88 g(P(3HB))/L) were achieved, comparing to the original recombinant strain (0.11 Cmol(OA)/Cmol(lac) and 7.8 g(P(3HB))/L, respectively). This methodology showed to be effective on the reduction of OA yield by consequently improving the P(3HB) yield on lactose (0.28 Cmol (P(3HB))/Cmol(lac) vs 0.10 Cmol(P(3HB))/Cmol(lac) of the original strain).
New biotechnology, Jan 29, 2015
Haloferax mediterranei was cultivated in highly saline medium using cheese whey as the substrate ... more Haloferax mediterranei was cultivated in highly saline medium using cheese whey as the substrate for the production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate), P(3HB-co-3HV). Acid hydrolysis provided a simple inexpensive method to obtain a cheese whey hydrolysate that was used for cultivation of H. mediterranei. Batch bioreactor cultivation of H. mediterranei resulted in the production of an active biomass concentration of 7.54gL(-1) with a polymer content of 53%, and a volumetric productivity of 4.04gL(-1)day(-1). Supplementation of the cultivation medium with micronutrients favored galactose consumption that was used for polymer synthesis after exhaustion of the available glucose. P(3HB-co-3HV) with a 3-hydroxyvalerate content of 1.5mol% was extracted from the biomass by hypo-osmotic shock. The polymer presented a molecular mass of 4.4×10(5), with a polydispersity index of 1.5. This work demonstrated the feasibility of using cheese whey for the production of a value-added bio...
Process Biochemistry, 2010