Escherichia coli (E. coli) strains are among the most frequently isolated microorganisms in urinary tract infections able to colonize the surface of urinary catheters and form biofilms. These biofilms are highly resistant to antibiotics and host immune system, resulting in increased morbidity and mortality rates. Strategies to prevent biofilm development, especially via restricting the initial stages of bacteria attachment are therefore urgently needed. Herein, a common urinary catheter material – polydimethylsiloxane (PDMS) – was covalently functionalized with antibacterial aminocellulose nanospheres (ACNSs) using the epoxy/amine grafting chemistry. The PDMS surface was pre-activated with (3-glycidyloxypropyl)-triethoxysilane to introduce epoxy functionalities prior to immobilization of the intact ACNSs via its amino groups. The AC biopolymer was first sonochemically processed into NSs improving by up to 80% its potential to prevent the E. coli biofilm formation on a polystyrene surface. The silicone surface decorated with these NSs demonstrated efficient inhibition of E. coli biofilms, reducing the total biomass when compared with pristine silicone material. Therefore, the functionalization of silicone-based materials with ACNSs shows promise as potential platform for prevention of biofilm-associated infections caused by E. coli.
Macedo, M.M.; Rivera, D.; Tzanov, T.; Šližyte, R.; Mozuraityte, R.; Lantto, R.; Rommi, K. Process biochemistry Vol. 50, num. 11, p. 1843-1851 DOI: 10.1016/j.procbio.2015.08.001 Data de publicació: 2015-08-12 Article en revista
Salmon backbones, co-streams of salmon processing industry, were transformed into stable, odour-free ingredients for cosmetics. First, the backbones were hydrolysed using commercial proteases (Bromelain + Papain, Trypsin, Corolase® 7089 and Protamex®) in order to accomplish the release of fish protein hydrolysates (FPH), which showed antioxidant activity and aptitude to inhibit skin-degrading and inflammatory enzymes. However, due to the FPH instability in aqueous solution and propensity for microbial contamination, their bioactive properties were entirely lost only after 24 h. To overcome the low stability and prevent the effect loss, a sonochemical technology was then employed to transform the FPH into stable tea tree oil-filled bioactive peptide-shell nanospheres (NS). Such transformation boosted the FPH antioxidant potential, which was further reflected in protection of fibroblasts from UV damage. In the form of NSs, the FPH resisted microbial contamination for more than 6 months and presented antimicrobial activity against Escherichia coli and Staphylococcus aureus. In addition, the fish odour was eliminated after the NSs processing, thus addressing this important challenge for using fish raw materials in cosmetics. This work suggests an alternative high value use of the fishery co-streams and expands their application potential beyond their current use as fish or animal feed
The performance of a biotrickling filter for the abatement of composting emissions was evaluated at short gas contact times of 2–10 s with a structured and an unstructured packing material. The effect of the gas contact time, pH control and water make-up flowrate were also evaluated during 8 months.
The average elimination capacity was 13 g N m-3 h-1 and 3.3 g C m-3 h-1 for NH3 and VOCs, respectively.
Maximum capacities obtained during an inlet concentration spiking experiment were 45 g N m-3 h-1 and 20 g C m-3 h-1 at a removal efficiency of 92.5 and 46.7%, respectively. A decrease of 40% was detected in the nitrification capacity when the hydraulic residence time increased from 2 to 5 h. Thus, water renewal was identified as a critical parameter to avoid substrate inhibition by nitrite and NH3 accumulation.
Results demonstrate that significant NH3 and VOCs removal efficiencies can be achieved for composting emissions in a biotrickling filter operated at short gas contact times, which entails a substantial reduction of operational and investment costs in comparison to traditional techniques.
Soley, A.; Fontova, A.; Gálvez, J.; Sarró, E.; Lecina, M.; Bragos, R.; Cairó, J.J.; Gòdia Casablancas, Francesc Process biochemistry Vol. 47, num. 4, p. 597-605 DOI: 10.1016/j.procbio.2011.12.022 Data de publicació: 2012-04 Article en revista
A simple disposable six minibioreactor system has been developed in order to perform multiple cell culture experiments in parallel, as a tool to accelerate experimentation in cell culture optimization. The system consists of a fixed part containing all instrumentation, sensors and actuators, and a disposable part, a compact unit with six minibioreactors with 10–15 mL of working volume each. This single-use unit is made of transparent biocompatible plastic material (polystyrene). Each one of the minibioreactors is equipped with agitation, headspace aeration supply and two optical probes, one for total cells measurement and pH, and another for dissolved oxygen measurement (and consequently the evaluation of Oxygen Uptake Rate, OUR). As an example of application, the performance of the system is successfully demonstrated for the culture of hybridoma cells growing in suspension under different conditions. The results allowed confirming the reproducibility of the system, and the feasibility to follow-up continuously the differences in cell growth, pH, pO2 and OUR evolution when hybridoma cells are cultured in different experimental conditions. For this, three different sets of experiments are considered. First, the use of the same culture medium DMEM supplemented with 10% fetal calf serum in all six minibioreactors. Second, the use of DMEM supplemented with three different FCS percentages (0, 1 and 10%) in two minibioreactors each. Third, the use of two different media (DMEM supplemented with 10% FCS and a chemically defined medium) in three minibioreactors each.
The variation of the contents in hexenuronic acids (HexA) and lignin in eucalyptus kraft pulp during sequences with the laccase–mediator treatment with or without xylanase pretreatment was studied. The laccase–HBT system (HBT: 1-hydroxybenzotriazole) initially oxidized lignin alone but altered
cellulose in the pulp as well after some time. Once all accessible lignin was removed, the system acted on HexA. As a result, the laccase–mediator treatment reduced the HexA content of the pulp, especially if a xylanase pretreatment was applied before. A previously unseen effect was observed here: HexA removal was found to depend on the laccase and HBT doses, but not on the reaction time. In addition, the xylanase pretreatment was found to strongly boost the effects of the laccase–HBT system by facilitating their access to HexA without affecting the lignin content.
Valls, C.; Molina, S.; Vidal, T.; del Rio, J.; Colom, J.F.; Martínez, Á.T; Gutíerrez, A.; Roncero, M.B. Process biochemistry Vol. 44, num. 9, p. 1032-1038 DOI: 10.1016/j.procbio.2009.05.002 Data de publicació: 2009-09 Article en revista
Carrillo, F.; Colom, X.; López, M.; Lis, M.; González, F.; Valldeperas, J. Process biochemistry Vol. 39, num. 2, p. 257-261 DOI: 10.1016/S0032-9592(03)00066-9 Data de publicació: 2003-10 Article en revista
he development of auto-regenerative biological life support systems for men in Space will be based on photosynthetic organisms, such as higher plants and algae, providing edible material. In this work, Spirulina platensis grown in a continuous photobioreactor was used to design a process for its recovery and further treatment to be used as food. Two different possibilities are studied (liquid or dry food). In each case, different steps are considered in the design of the process and further characterised: cell harvesting, washing, pasteurisation and spry-drying. Special emphasis is made on biomass quality, both in terms of potential microbial contamination and changes in its composition during the different steps of the process. Cell harvesting was conducted with a net recovery of solids and water higher than 95% with a solids concentration factor about 20–30. Biomass quality was shown as satisfactory in all the treatments tested.
The development of auto-regenerative biological life support systems for men in Space will be based on photosynthetic organisms, such as higher plants and algae, providing edible material. In this work, Spirulina platensis grown in a continuous photobioreactor was used to design a process for its recovery and further treatment to be used as food. Two different possibilities are studied (liquid or dry food). In each case, different steps are considered in the design of the process and further characterised: cell harvesting, washing, pasteurisation and spry-drying. Special emphasis is made on biomass quality, both in terms of potential microbial contamination and changes in its composition during the different steps of the process. Cell harvesting was conducted with a net recovery of solids and water higher than 95% with a solids concentration factor about 20–30. Biomass quality was shown as satisfactory in all the treatments tested.