Production of surfactants from bio-materials

Este trabalho foi desenvolvido no âmbito de um projecto europeu, BIOPRODUCTION, tendo em vista o desenvolvimento de dois tipos de biomaterias funcionais: ésteres de açúcares com ácidos gordos (SFAE) e metacrilatos funcionais. A síntese laboratorial do biosurfactante SFAE foi efectuada utilizando como matérias-primas diferentes sacáridos, nomeadamente sacarose, glucose e melaço de cana-de-açúcar (mistura de polissacáridos), e ésteres metílicos de ácidos gordos (FAME) de óleos vegetais, tais como colza e coco. Esta síntese é constituída por dois passos: acilação dos açúcares com anidrido acético, e transesterificação do açúcar acilado com FAME, utilizando triflatos de lantanídeos como catalisador. Diferentes estequiometrias foram testadas, bem como diferentes processos de modo a evitar a degradação dos açúcares. Foram efectuados testes preliminares de emulsão e calculou-se, empiricamente, o respectivo HLB. Procedeu-se à caracterização do produto através de FTIR e RMN e também à optimização iterativa do processo de síntese. A modificação, à escala laboratorial, de metacrilatos de metilo (MMA) realizou-se recorrendo à sua transesterificação com polióis convencionais. Efectuaram-se testes de reticulação do produto com diferentes catalisadores e iniciadores para posterior aplicação em revestimentos de borracha. Por fim, para ambos os produtos serão necessários estudos adicionais de caracterização, nomeadamente tensão superficial para os biosurfactantes e propriedades mecânicas para polímeros modificados com MMA.

A new cloning system based on the OprI lipoprotein for the production of recombinant bacterial cell wall-derived immunogenic formulations

The conjugation of antigens with ligands of pattern recognition receptors (PRR) is emerging as a promising strategy for the modulation of specific immunity. Here, we describe a new Escherichia coli system for the cloning and expression of heterologous antigens in fusion with the OprI lipoprotein, a TLR ligand from the Pseudomonas aeruginosa outer membrane (OM). Analysis of the OprI expressed by this system reveals a triacylated lipid moiety mainly composed by palmitic acid residues. By offering a tight regulation of expression and allowing for antigen purification by metal affinity chromatography, the new system circumvents the major drawbacks of former versions. In addition, the anchoring of OprI to the OM of the host cell is further explored for the production of novel recombinant bacterial cell wall-derived formulations (OM fragments and OM vesicles) with distinct potential for PRR activation. As an example, the African swine fever virus ORF A104R was cloned and the recombinant antigen was obtained in the three formulations. Overall, our results validate a new system suitable for the production of immunogenic formulations that can be used for the development of experimental vaccines and for studies on the modulation of acquired immunity.

Production of hydroxamic acids by immobilized Pseudomonas aeruginosa cells Kinetic analysis in reverse micelles

Intact cells from Pseudomonas aeruginosa strain L10 containing amidase were used as biocatalysts both free and immobilized in a reverse micellar system. The apparent kinetic constants for the transamidation reaction in hydroxamic acids synthesis, were determined using substrates such as aliphatic, amino acid and aromatic amides and esters, in both media. In reverse micelles, K-m values decreased 2-7 fold relatively to the free biocatalyst using as substrates acetamide, acrylamide, propionamide and glycinamide ethyl ester. We have concluded that overall the affinity of the biocatalyst to each substrate increases when reactions are performed in the reversed micellar system as opposed to the buffer system. The immobilized biocatalyst in general, exhibits higher stability and faster rates of reactions at lower substrates concentration relatively to the free form, which is advantageous. Additionally, the immobilization revealed to be suitable for obtaining the highest yields of hydroxamic acids derivatives, in some cases higher than 80%. (C) 2013 Elsevier B.V. All rights reserved.

Study of the production of polyesters for polyurethanes at pilot plant scale

Dissertação para obtenção do grau de Mestre em Engenharia Química

Biomass production of four Cynara cardunculus clones and lignin composition analysis

Four Cynara cardunculus clones, two from Portugal and two from Spain were studied for biomass production and their lignin was characterized. The clones differed in biomass partitioning: Spanish clones produced more capitula (54.5% vs. 43.9%), and Portuguese clones more stalks (37.2% vs. 25.6%). The heating values (HHV0) of the stalks were similar, ranging from 17.1 to 18.4 MJ/kg. Lignin was studied by analytical pyrolysis (Py-GC/MS(FID)), separately in depithed stalks (stalksDP) and pith. StalksDP had in average higher relative proportions of lignin derived compounds than pith (23.9% vs. 21.8%) with slightly different lignin monomeric composition: pith samples were richer in syringyl units as compared to stalksDP (64% vs. 53%), with S/G ratios of 2.1 and 1.3, respectively. The H:G:S composition was 7:40:53 in stalksDP and 7:29:64 in pith. The lignin content ranged from 18.8% to 25.5%, enabling a differentiation between clones and provenances. © 2015 Elsevier Ltd. All rights reserved.