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). (...)

Structural and enzymatic characterization of ABgp46, a novel phage endolysin with broad anti-Gram-negative bacterial activity

The present study demonstrates the antibacterial potential of a phage endolysin against Gram-negative pathogens, particularly against multidrug resistant strains of Acinetobacter baumannii. We have cloned, heterologously expressed and characterized a novel endolysin (ABgp46) from Acinetobacter phage vb_AbaP_CEB1 and tested its antibacterial activity against several multidrug-resistant A. baumannii strains. LC-MS revealed that ABgp46 is an N-acetylmuramidase, that is also active over a broad pH range (4.0-10.0) and temperatures up to 50°C. Interestingly, ABgp46 has intrinsic and specific anti-A. baumannii activity, reducing multidrug resistant strains by up to 2 logs within 2 hours. By combining ABgp46 with several organic acids that act as outer membrane permeabilizing agents, it is possible to increase and broaden antibacterial activity to include other Gram-negative bacterial pathogens. In the presence of citric and malic acid, ABgp46 reduces A. baumannii below the detection limit (> 5 log) and more than 4 logs P. aeruginosa and Salmonella Typhimurium strains. Overall, this globular endolysin exhibits a broad and high activity against Gram-negative pathogens, that can be enhanced in presence of citric and malic acid, and be used in human and veterinary medicine.

Bacterial nanocellulose as a structured platform for conductive biopolymers

[Exert] Since the discovery that polyacetylene could be doped to the metallic state more than 3 decades ago, an ever-growing body of a multidisciplinary approach to material design, synthesis, and system integration has been evidenced. The present chapter will primarily review the emerging field of intrinsically conducting polymer and conductive polymer blends, with polyaniline and polypyrrole as the major representatives of conducting polymers. This survey will also address some of the potential areas for applications of such conductive polymer blends. Also, current results concerning the chemical polymerization of conducting polymers on bacterial nanocellulose (BNC) will be presented, including brief remarks on the rationale for the use of conductive BNC blends. This will be followed by a discussion on their properties and potential applications (...).

Bacterial cellulose surface modification

The unique properties of bacterial nanocellulose (BNC) provide the basis for a wide range of applications in human and veterinary medicine, odontology, pharmaceuticals, acoustic and filter membranes, biotechnological devices, and in the food and paper industry. In this chapter, an overview of surface modifications of bacterial cellulose is presented. Depending on the envisaged applications, chemical modifications, incorporation of bioactive molecules, modification of the porosity, crystallinity, and biodegradability may be obtained, further enlarging the potential of BNC.

Laccase immobilization on bacterial nanocellulose membranes: antimicrobial, kinetic and stability properties

This work studied the physical immobilization of a commercial laccase on bacterial nanocellulose (BNC) aiming to identify the laccase antibacterial properties suitable for wound dressings. Physico-chemical analysis demonstrates that the BNC structure is manly formed by pure crystalline I cellulose. The pH optimum and activation energy of free laccase depends on the substrate employed corresponding to pH 6, 7, 3 and 57, 22, 48 kJ mol1 for 2,6-dimethylphenol (DMP), catechol and 2,2 -azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), respectively. The Michaelis-Menten constant (Km) value for the immobilized laccase (0.77 mM) was found to be almost double of that of the free enzyme (0.42 mM). However, the specific activities of immobilized and free laccase are similar suggesting that the cage-like structure of BNC allows entrapped laccase to maintain some flexibility and favour substrate accessibility. The results clearly show the antimicrobial effect of laccase in Gram-positive (92%) and Gram-negative (26%) bacteria and cytotoxicity acceptable for wound dressing applications.

Bacterial cellulose-lactoferrin as an antimicrobial edible packaging

Bacterial cellulose (BC) films from two distinct sources (obtained by static culture with Gluconacetobacter xylinus ATCC 53582 (BC1) and from a commercial source (BC2)) were modified by bovine lactoferrin (bLF) adsorption. The functionalized films (BC+bLF) were assessed as edible antimicrobial packaging, for use in direct contact with highly perishable foods, specifically fresh sausage as a model of meat products. BC+bLF films and sausage casings were characterized regarding their water vapour permeability (WVP), mechanical properties, and bactericidal efficiency against two food pathogens, Escherichia coli and Staphylococcus aureus. Considering their edibility, an in vitro gastrointestinal tract model was used to study the changes occurring in the BC films during passage through the gastrointestinal tract. Moreover, the cytotoxicity of the BC films against 3T3 mouse embryo fibroblasts was evaluated. BC1 and BC2 showed equivalent density, WVP and maximum tensile strength. The percentage of bactericidal efficiency of BC1 and BC2 with adsorbed bLF (BC1+bLF and BC2+bLF, respectively) in the standalone films and in inoculated fresh sausages, was similar against E. coli (mean reduction 69 % in the films per se versus 94 % in the sausages) and S. aureus (mean reduction 97 % in the films per se versus 36 % in the case sausages). Moreover, the BC1+bLF and BC2+bLF films significantly hindered the specific growth rate of both bacteria. Finally, no relevant cytotoxicity against 3T3 fibroblasts was found for the films before and after the simulated digestion. BC films with adsorbed bLF may constitute an approach in the development of bio-based edible antimicrobial packaging systems.

Novel strategies to combat gram-negative bacterial pathogens using bacteriophage proteins

Dissertação de mestrado em Bioengenharia

Influence of oxygen conditions on bacterial interactions within biofilms related with cystic fibrosis

Dissertação de mestrado em Bioengineering

Insights into bacterial colony morphology evolution and diversification during infection development in cystic fibrosis

Tese de Doutoramento em Engenharia Biomédica.