Studies on the use of purified CBH I for oligosaccharide synthesis

The importance of biologically active carbohydrates has been recognized over the last decade. The availability of cheap oligosaccharides for biological activity studies is very reduced. The isolation of these compounds from natural sources is almost impossible, because of their very high specific activity. and consequently very low concentration in nature. As chemical synthesis is a difficult and time consuming, the enzymatic synthesis has been regarded over the last years as a very attractive methodology for oligosaccharide production. The main approach when utilizing glycanases for di- or trisaccharides synthesis has been the transglycosylation reaction. However, the isolation of products is quite complicated. On the other hand, the condensation reaction by reversed hydrolysis activity, which in many cases requires cheaper substrates. has a very low yield. In this work, a purified exoglucanase CBH I from the fungus Trichoderma reesei was analyzed for its reversed hydrolysis activity. The enzyme was purified by conventional methodologies (preparative isoelectric focusing, gel filtration on Sephacryl 100 HR, anionic exchange on a Mono Q column and cationic exchange on a Mono S column), from a commercial cellulase, Cellulast, from Novo. The activity of the purified enzyme on a large set of substrates, such as lichenan, laminarin, filter paper, acid swollen Avicel, xylan and carboxymethylcellulose was characterized, suggesting that it is basically free of contaminant activities. The enzyme was incubated in aqueous media with high sugar concentrations. Several mono- and disaccharides were used, in order to study the enzyme specificity. The obtained products were analyzed in a Dionex chromatographer using a CarboPac PA-100 column. The separated reaction products were analysed by NMR. The yields of the condensation reaction were in several cases considerably high

Nata organisms: an overview on the fermentative microbial ecosystem

Publicado em "Abstracts of papers - American Chemical Society", vol. 245The Acetobacter and Gluconacetobacter genus (both from the Acetobacteraceae family) are the most notable acetic acid producers, their intermediate metabolites being exploited biotechnologicaly for the production of vinegar, Kombucha, cocoa and nata de coco. Extensive efforts are being made to better understand the dynamic interplay of microbial populations during fermentation processes, with ample literature existing on virtually every food product currently being consumed. In the case of nata de coco, Gluconacetobacter strains have been found to play a key role in cellulose production. Despite abundant literature with isolated cellulose−producing strains, little work has been done in analysing population dynamics of the microbial communities. This presentation will address the microbial interplay in the production of nata de coco, with an overview of the taxonomy of the major acetic acid strains involved. An overview on the efforts and potential implications of upgrading nata de coco production through biotechnology will also be addressed

Chitosan-based nanoparticles prepared by template polymerization

INTRODUCTION: Chitosan (CS) /poly(acrylic acid) (PAA) nanoparticles (NPs) have recently been obtained by template polymerization1. In this technique, the NPs are produced upon polymerization of an acrylic monomer next to the chitosan backbone. Due to the electrostatic interaction, the negatively charged acrylic monomers align along the chitosan molecules. These physic interactions leads to self-assembled particles. The molecular weight and deacetylation degree of chitosan affect the solubility, size, and stability of the particles. (...)(undefined

Bacterial NanoCellulose: what future?

Acetic acid bacteria (AAB) have been used in various fermentation processes. Of several ABB, the bacterial nanocellulose (BNC) producers, notably Komagataeibacter xylinus, appears as an interesting species, in large part because of their ability in the secretion of cellulose as nano/microfibrils. In fact, BNC is characterized by a native nanofibrillar structure, which may outperform the currently used celluloses in the food industry as a promising novel hydrocolloid additive. During the last couple of years, a number of companies worldwide have introduced some BNC-based products to the market. The main aim of this editorial is to underline the BNC potentials.info:eu-repo/semantics/publishedVersio

Bacterial cellulose from lab to market

Book of Abstracts of CEB Annual Meeting 2017Bacterial nanocellulose (BNC) is a nanofibrilar exopolysaccharide synthesized by certain Gram-negative, obligate aerobic, acetic acid bacteria, the Komagataeibacter genus being the most important due to the high cellulose yield obtained. The unique properties of this biopolymer have supported a wide range of potential applications, in human and veterinary medicine, odonthology, pharmaceutical industry, acoustic and filter membranes, biotechnological devices and in the food and paper industry. The largescale production of BNC, through advanced biotechnology has eluded many researches. Historical attempts but on low volume and high-value (mostly for biomedical applications) production can be traced back to the 90s. This presentation will show the main work with BNC by the Funcarb group. Examples of these studies will include the use of BNC in biomedical and food applications. Finally, an overview on the main efforts towards the production of BNC at large scale and potential markets will also be presented.info:eu-repo/semantics/publishedVersio

Characterization of the self-assembly process of hydrophobically modified dextrin

Hydrophobized dextrin, randomly substituted by long alkyl chain (C16), forms stable hydrogel nanoparticles by self-assembling in water. Hydrophobic chains, distributed along the polymer backbone, promote the formation of hydrophobic microdomains within the nanoparticles. The influence of degree of substitution with hydrophobic chains (DSC16) on nanoparticles size, colloidal stability, density, aggregation number and nanoparticle weight was studied. Size distribution was also evaluated at different pH, urea concentration and ionic strength conditions. As shown by dynamic light scattering and transmission electron microscopy, the particles are spherical having a diameter of about 20 nm. The more substituted polymer forms more densely packed hydrophobic microdomains, such that the colloidal stability (in water and PBS buffer) of nanoparticles is increased. The knowledge of the aggregate building process and the characteristics of the nanoparticles are crucial for the design of drug delivery systems.Fundação para a Ciência e a Tecnologia (FCT) - SFRH/BD/22242/2005, POCTI/ BIO/45356/2002

A spin-offs journey into achieving marketable products from bacterial cellulose

[Excerpt] Academic spin-offs, technological ventures born inside Universities, have increasingly strengthen the connections between the scholarship and the economy, by fostering the role of technology transfer and knowledge commercialization. This presentation will outline the major steps in taking an idea or a technology to market, growing the venture and aiming at securing a successful exit. Also, it will present BCTechnologies (Bacterial Cellulose Technologies), a spin-off from the University of Minho (Portugal). (...