Suchergebnisse

Polyurethane-ureas are a versatile family of polymers which can be employed in a wide range of applications. Among them, waterborne polyurethane-urea (WBPUU) dispersions are gaining relevance in the field of environmentally-friendly products since their productive process adopts green synthesis routes, avoiding the use of organic solvents. Furthermore, their waterborne character can be exploited to incorporate several water compatible ingredients able to confer functional properties to the final materials. Among them, plant extracts, which are known to have relevant bioactivities, can be viewed as interesting candidates. Therefore, in this work, two extracts known to present antimicrobial activity (Melissa officinalis L. and Salvia officinalis L.) were obtained by the infusion method and incorporated into the WBPUU (1, 3 and 5 wt%) following different incorporation routes comprising its adding during different phases of the productive process (post-, in-situ and pre- methods). Thereafter films were prepared by solvent-casting and characterized from the viewpoint of physicochemical, thermal, mechanical, thermomechanical and antibacterial properties and morphologically. The studied incorporation routes resulted in different intercalation mechanisms that varied from extract positioned among the polyurethane-urea nanoparticles (post-method) to extract partially embedded inside them (in-situ and pre-methods), which produced stiffening or flexibilizing effects in the produced films, enhancing in general the antimicrobial characteristics of films after 4 days of incubation comparing with base WBPUU, especially when the extract is embedded. ; Financial support from the Basque Government (IT-776-13), the Spanish Ministry of Economy and Competitiveness (MINECO) (MAT2016-76294-R), POCI-01-0145-FEDER-006984 (LA LSRE-LCM) funded by ERDF through POCI-COMPETE2020 and FCT and NORTE-01-0145-FEDER-000006, funded by NORTE 2020, under PT2020 through ERDF is gratefully acknowledged. We also wish to acknowledge the "Macrobehaviour- Mesostructure-Nanotechnology" SGIker units from the University of the Basque Country, for their technical support. A.S-E thanks the University of the Basque Country for Ph.D. grant (PIF/UPV/12/201). ; Financial support from the Basque Government (IT-776-13), the Spanish Ministry of Economy and Competitiveness (MINECO) (MAT2016-76294-R), POCI-01-0145-FEDER-006984 (LA LSRE-LCM) funded by ERDF through POCI-COMPETE2020 and FCT and NORTE- 01-0145-FEDER-000006, funded by NORTE 2020, under PT2020 through ERDF is gratefully acknowledged. We also wish to acknowledge the "Macrobehaviour- Mesostructure-Nanotechnology" SGIker units from the University of the Basque Country, for their technical support. A.S-E thanks the University of the Basque Country for Ph.D. grant (PIF/UPV/12/201). ; info:eu-repo/semantics/publishedVersion

13 p.-5 fig. ; Komagataeibacter medellinensis ID13488 (formerly Gluconacetobacter medellinensis ID13488) is able to produce crystalline bacterial cellulose (BC) under high acidic growth conditions. These abilities make this strain desirable for industrial BC production from acidic residues (e.g. wastes generated from cider production). To explore the molecular bases of the BC biosynthesis in this bacterium, the genome has been sequenced revealing a sequence of 3.4 Mb containing three putative plasmids of 38.1 kb (pKM01), 4.3 kb (pKM02) and 3.3 Kb (pKM03). Genome comparison analyses of K. medellinensis ID13488 with other cellulose-producing related strains resulted in the identification of the bcs genes involved in the cellulose biosynthesis. Genes arrangement and composition of four bcs clusters (bcs1, bcs2, bcs3 and bcs4) was studied by RT-PCR, and their organization in four operons transcribed as four independent polycistronic mRNAs was determined. qRT-PCR experiments demonstrated that mostly bcs1 and bcs4 are expressed under BC production conditions, suggesting that these operons direct the synthesis of BC. Genomic differences with the close related strain K. medellinensis NBRC 3288 unable to produce BC were also described and discussed. ; The authors thank for the financial support from the Foundation Domingo Martınez (2015-Area Materiales 2), the Spanish Ministry of Science, Innovation and Universities (MAT2016-76294-R, BIO2017-83448-R), the Community of Madrid (P2013/MIT2807), the Basque Government in the frame of Grupos Consolidados (IT-776-13). L.U. PIF PRE_2014_1_371. ; Peer reviewed