Exopolysaccharides enriched in rare suggars: bacterial sources, production and applications

Mini ReviewMicrobial extracellular polysaccharides (EPS), produced by a wide range of bacteria, are high molecular weight biopolymers, presenting an extreme diversity in terms of chemical structure and composition. They may be used in many applications, depending on their chemical and physical properties. A rather unexplored aspect is the presence of rare sugars in the composition of some EPS. Rare sugars, such as rhamnose or fucose, may provide EPS with additional biological properties compared to those composed of more common sugar monomers. This review gives a brief overview of these specific EPS and their producing bacteria. Cultivation conditions are summarized, demonstrating their impact on the EPS composition, together with downstream processing. Finally, their use in different areas, including cosmetics, food products, pharmaceuticals, and biomedical applications, are discussedinfo:eu-repo/semantics/publishedVersio

Post-transcriptional control in the regulation of polyhydroxyalkanoates synthesis

Funding Information: Funding: Work at ITQB NOVA was financially supported by the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie ID: 867437, and projects UIDB/04612/2020 and UIDP/04612/2020 (Molecular, Structural and Cellular Microbiology), funded by FEDER through COMPETE 2020—Programa Operacional Competitividade e Internacionalização (POCI) and by national funds through FCT—Fundação para a Ciência e a Tecnologia; Work at NOVA School of Science and Technology FCT I.P., was funded by national funds from FCT—Fundação para a Ciência e a Tecnologia, I.P., in the scope of the project UIDP/04378/2020 and UIDB/04378/2020 of the Research Unit on Applied Molecular Biosciences—UCIBIO and the project LA/P/0140/2020 of the Associate Laboratory Institute for Health and Bioeconomy-i4HB. Funding Information: Work at ITQB NOVA was financially supported by the European Union?s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie ID: 867437, and projects UIDB/04612/2020 and UIDP/04612/2020 (Molecular, Structural and Cellular Microbiology), funded by FEDER through COMPETE 2020?Programa Operacional Competitividade e Internacionaliza??o (POCI) and by national funds through FCT?Funda??o para a Ci?ncia e a Tecnologia; Work at NOVA School of Science and Technology FCT I.P., was funded by national funds from FCT?Funda??o para a Ci?ncia e a Tecnologia, I.P., in the scope of the project UIDP/04378/2020 and UIDB/04378/2020 of the Research Unit on Applied Molecular Biosciences?UCIBIO and the project LA/P/0140/2020 of the Associate Laboratory Institute for Health and Bioeconomy-i4HB. Publisher Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland.The large production of non-degradable petrol-based plastics has become a major global issue due to its environmental pollution. Biopolymers produced by microorganisms such as polyhy-droxyalkanoates (PHAs) are gaining potential as a sustainable alternative, but the high cost associated with their industrial production has been a limiting factor. Post-transcriptional regulation is a key step to control gene expression in changing environments and has been reported to play a major role in numerous cellular processes. However, limited reports are available concerning the regulation of PHA accumulation in bacteria, and many essential regulatory factors still need to be identified. Here, we review studies where the synthesis of PHA has been reported to be regulated at the post-transcriptional level, and we analyze the RNA-mediated networks involved. Finally, we discuss the forthcoming research on riboregulation, synthetic, and metabolic engineering which could lead to improved strategies for PHAs synthesis in industrial production, thereby reducing the costs currently associated with this procedure.publishersversionpublishe

Low temperature dissolution of yeast chitin-glucan complex and characterization of the regenerated polymer

Chitin-glucan complex (CGC) is a copolymer composed of chitin and glucan moieties extracted from the cell-walls of several yeasts and fungi. Despite its proven valuable properties, that include antibacterial, antioxidant and anticancer activity, the utilization of CGC in many applications is hindered by its insolubility in water and most solvents. In this study, NaOH/urea solvent systems were used for the first time for solubilization of CGC extracted from the yeast Komagataella pastoris. Di erent NaOH/urea ratios (6:8, 8:4 and 11:4 (w/w), respectively) were used to obtain aqueous solutions using a freeze/thaw procedure. There was an overall solubilization of 63–68%, with the highest solubilization rate obtained for the highest tested urea concentration (8 wt%). The regenerated polymer, obtained by dialysis of the alkali solutions followed by lyophilization, formed porous macrostructures characterized by a chemical composition similar to that of the starting co-polymer, although the acetylation degree decreased from 61.3% to 33.9–50.6%, indicating that chitin was converted into chitosan, yielding chitosan-glucan complex (ChGC). Consistent with this, there was a reduction of the crystallinity index and thermal degradation temperature. Given these results, this study reports a simple and green procedure to solubilize CGC and obtain aqueous ChGC solutions that can be processed as novel biomaterialsinfo:eu-repo/semantics/publishedVersio

Evolution in swimming "science" research

Swimming seems to be one of the sports more studied . More than one decade ago, Clarys (1996) made an content analysis of the research about swimming. However, in these last 13 years several developments happened in the aquatic activities

Sludge retention time impacts on polyhydroxyalkanoate productivity in uncoupled storage/growth processes

SFRH/BD/104767/2014 program ( GA 773375 ) UIDP/04378/2020 UIDB/04378/2020The process involving mixed microbial cultures (MMCs) and waste-based substrates emerged as an alternative solution to reduce the market price of polyhydroxyalkanoates (PHAs). The selection of an efficient MMC that displays a significant PHA accumulation potential and a high growth rate is considered a key factor for the MMC PHA production feasibility. This study used a pilot plant to investigate the dynamics of growth vs storage in a mixed culture fed with fermented fruit waste under uncoupled carbon and nitrogen feeding. Varying sludge retention times (SRTs) (2 and 4 d) and organic loading rates (OLRs) (from 2.6 to 14.5 gCOD.L−1.d−1) were imposed for this purpose. Results showed that, regardless of the OLR imposed, cultures selected at lower SRT grew faster and more efficiently using stored PHA. However, they had inferior specific storage rates and accumulation capacity, resulting in lower PHA productivity. Additionally, the polymer storage yield was independent of the SRT, and was directly linked with the abundance of putative PHA-storers in the MMC. The high PHA productivity (4.6 ± 0.3 g.L−1.d−1) obtained for the culture selected at 4 d of SRT was 80% above that obtained for the lower SRT tested, underlining the importance of achieving a good balance between culture growth and accumulation capacity to increase the viability of the PHA-producing process from wastes.publishersversionpublishe

Evolution on Swimming Science Research: content analysis of the “Biomechanics and Medicine in Swimming” Proceedings Books from 1971 to 2006

Swimming seems to be one of the sports more studied . More than one decade ago, Clarys (1996) made an content analysis of the research about swimming. However, in these last 13 years several developments happened in the aquatic activities

Characterization of the Thermostable Biosurfactant Produced by Burkholderia thailandensis DSM 13276

Funding Information: Technology: 31961133015; Shandong University: 31961133014). C.V.G., A.E. and A.T.R. acknowledge FCT I.P. for the Ph.D. grants 2021.05798.BD, 2021.05014.BD and 2020.06470.BD, respectively. Funding Information: ThTeh ethgelrymcoalli pstoapbeilpittyid oef bthioesuBr. ftahcatialanntdseencsriestbediobsuyrBfaucrtkahnotl dweraisa ethvaailluanatdeedn sbisyD exSpMos1i3n2g7 6 thwe absiodpeomlyomnsetrr aitne danto apquosesoeusss svoalluutaiobnle tsou raf atecme-apcetriavteuprer oopfe 1r2ti1e s°,Cnainm aenly ,aautloowclaCvMe (C0.9a8nd bar) for 20 min. Interestingly, the treated solution maintained its shear-thinning behavior, with a slight increase in the flow behavior index value (0.46) compared to the untre◦ ated biosurfactant solution (0.44) (refer to Figure S4 for supporting information on fitting the power law model). The thermally treated biosurfactant also maintained a surface tension value of 40.36 ± 0.5 mN/m, which was identical to that of the untreated solution (40.31 ± 0.agent26 mNin/mfood), thus conand/orfirmcosmeticing its prthermoducts/pral stabocessing,ility. and for bioremediation. The emulsifying ability of the treated biosurfactant, on the other hand, was negatively affected, with a reduction in the EA to 50.5 ± 0.9%, which is around half of the value observed for the non-treated biosurfactant (100.0 ± 0.0%). Different biosurfactants (e.g., glAyucothliopridCso)n atrlisbousthioonws:eCdoan scleipgthuta dliezcartieoans,eC i.nV.tGh.e, eF.mF.ualnsdifyCi.nAg.Vc.aTp.;amciettyhoadftoelroghye,aCt .tVre.Ga.t,mAe.Tn.tR ., at similar temperatures [64]. Nevertheless, the value is still within the range reported for good EA (≥50%) [59]. Moreover, Triton X-100 also suffered a similar reduction in its emulsification ability, as the EA of the emulsions stabilized with the autoclaved compound also reduced from 43.9 ± 2.1% to 33.4 ± 5.2%. These results underline the potential of the B. thIa.Pil.a, nindetnhseisscboipoesuorfftahcetapnrot jfeocrts uUseID, fPo/r0e4x37a8m/p20le20, ianntdheU fIDooBd/ 0i4n3d7u8/st2r0y2,0 inofwthheicRhestheaercthemUpneitr-on atAuprepslieadreMeolleevcuatlaerdBdiouscriienngcepsr—oUceCsIsBiInOgaonrd tthhee fpirnoajelcpt rLoAd/uPc/t0 i1s40c/o2n0s2u0mofetdh.e Associate Laboratory Institute for Health and Bioeconomy—i4HB, and by the European Union’s Horizon 2020 research and 4. Coninnovcalustionioprnos gram through Project Bio Innovation of a Circular Economy for Plastics (BioICEP), under The glycolipopeptide biosurfactant secreted by Burkholderia thailandensis DSM 13276 numbers: Institute of Microbiology, Chinese Academy of Sciences: 31961133016; Beijing Institute of was demonstrated to possess valuable surface-active properties, namely, a low CMC and high EA for almond and sunflower oils, and for benzene. Moreover, the biosurfactant showed good thermostability, with a thermal degradation temperature above 200 °C, and the ability to maintain stable rheological and surface-active properties, as well as good EA Publisher Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland.Biosurfactants synthesized by microorganisms represent safe and sustainable alternatives to the use of synthetic surfactants, due to their lower toxicity, better biodegradability and biocompatibility, and their production from low-cost feedstocks. In line with this, the present study describes the physical, chemical, and functional characterization of the biopolymer secreted by the bacterium Burkholderia thailandensis DSM 13276, envisaging its validation as a biosurfactant. The biopolymer was found to be a glycolipopeptide with carbohydrate and protein contents of 33.1 ± 6.4% and 23.0 ± 3.2%, respectively. Galactose, glucose, rhamnose, mannose, and glucuronic acid were detected in the carbohydrate moiety at a relative molar ratio of 4:3:2:2:1. It is a high-molecular-weight biopolymer (1.0×107Da) with low polydispersity (1.66), and forms aqueous solutions with shear-thinning behavior, which remained after autoclaving. The biopolymer has demonstrated a good emulsionstabilizing capacity towards different hydrophobic compounds, namely, benzene, almond oil, and sunflower oil. The emulsions prepared with the biosurfactant, as well as with its autoclaved solution, displayed high emulsification activity (>90% and ~50%, respectively). Moreover, the almond and sunflower oil emulsions stabilized with the biosurfactant were stable for up to 4 weeks, which further supports the potential of this novel biopolymer for utilization as a natural bioemulsifier.publishersversionpublishe

Preparation and characterization of films based on a natural P(3HB)/mcl-PHA blend obtained through the co-culture of Cupriavidus necator and Pseudomonas citronellolis in apple pulp waste

The co-culture of Cupriavidus necator DSM 428 and Pseudomonas citronellolis NRRL B-2504 was performed using apple pulp waste from the fruit processing industry as the sole carbon source to produce poly(3-hydroxybutyrate), P(3HB) and medium-chain length PHA, mcl-PHA, respectively. The polymers accumulated by both strains were extracted from the co-culture’s biomass, resulting in a natural blend that was composed of around 48 wt% P(3HB) and 52 wt% mcl-PHA, with an average molecular weight of 4.3 105 Da and a polydispersity index of 2.2. Two melting temperatures (Tm) were observed for the blend, 52 and 174 C, which correspond to the Tm of the mcl-PHA and P(3HB), respectively. P(3HB)/mcl-PHA blend films prepared by the solvent evaporation method had permeabilities to oxygen and carbon dioxide of 2.6 and 32 Barrer, respectively. The films were flexible and easily deformed, as demonstrated by their tensile strength at break of 1.47 0.07 MPa, with a deformation of 338 19% until breaking, associated with a Young modulus of 5.42 1.02 MPa. This study demonstrates for the first time the feasibility of using the co-culture of C. necator and P. citronellolis strains to obtain a natural blend of P(3HB)/mcl-PHA that can be processed into films suitable for applications ranging from commodity packaging products to high-value biomaterialsinfo:eu-repo/semantics/publishedVersio

Production of Medium-Chain Length Polyhydroxyalkanoates by Pseudomonas citronellolis Grown in Apple Pulp Waste

Background and objective: Apple pulp waste generated by the fruit processing industry is a sugar-rich material with great potential to be used as a feedstock for production of value added microbial products. The aim of this work was to use this feedstock for the cultivation of Pseudomonas citronellolis and production of medium-chain-length polyhydroxyalkanoates, a natural elastomer.Material and methods: The solid fraction of the apple pulp waste was discarded and the soluble fraction, rich in fructose (17.7 g l-1), glucose (7.5 g l-1) and sucrose (1.2 g l-1), was used for the batch bioreactor cultivation of Pseudomonas citronellolis NRRL B-2504.Results and conclusion: Pseudomonas citronellolis reached a polymer content in the biomass of 30% wt and a volumetric productivity of 0.025 g l-1 h-1. The polymer was mainly composed of 3-hydroxydecanoate (68% mol) and 3-hydroxyoctanoate (22% mol), with minor contents of 3-hydroxydodecanoate (5% mol), 3-hydroxytetradecanoate (4% mol) and 3-hydroxyhexanoate (1% mol), and had a molecular weight of 3.7×105 Da. It presented glass transition and melting temperatures of -12 and 53°C, respectively, and a thermal degradation temperature of 296°C. The polymer’s films were dense, ductile and permeable to oxygen and carbon dioxide. These results demonstrated that apple pulp waste is a suitable feedstock for the production of a biopolymer with properties that render it a promising alternative to some synthetic petrochemical-derived polyesters.Conflict of interest: The authors declare no conflict of interest

Polymyxin-Resistant Acinetobacter spp. Isolates: What is Next?

Univ Fed Sao Paulo, Div Infect Dis, Lab Especial Microbiol Clin, BR-04025010 Sao Paulo, SP, BrazilUniv Fed Sao Paulo, Div Infect Dis, Lab Especial Microbiol Clin, BR-04025010 Sao Paulo, SP, BrazilWeb of Scienc