Percorrer por autor "Crugeira, Pedro"
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- Bacterial cellulose biosynthesis in the presence of raw moist olive pomace: A green sustainable approach that enhances biopolymer production and propertiesPublication . Crugeira, Pedro; Khelifa, Halima; Barreira, Luísa; Halla, Noureddine; Barreiro, Filomena; Rodrigues, Paula; Peres, António M.; Schreiner, Tatiana B.; Schreiner, Tatiana B.In this study, the biosynthesis of bacterial cellulose (BC) by Komagataeibacter intermedius strain isolated from Kombucha tea in the presence of raw moist olive pomace (MOP) (concentration up to 40 % in the fermentation media) was studied. The BC membranes were characterized by their antioxidant activity, structural character- istics, crystallinity, thermal stability, and mechanical behavior. Using raw MOP activated the inherent activity of the phenolic compounds, leading to cellular adaptation under unfavorable conditions and increased BC pro- duction for all tested MOP concentrations (p < 0.0001). This led to a 166.61 % increase for the 20 % MOP group compared to the control (HS medium). For this sample, enhanced antioxidant activity (~40-fold higher than the control) was found, which might be associated with the molecular interactions established between hydroxyls of BC and phenolic compounds. Moreover, an increase of 603.03 % in strain capacity, and a 376.01 % improvement in stress at break compared to the control was observed. The study confirmed that BC can be synthesized using MOP in its natural state, supporting a sustainable circular economy while enhancing the biosynthesis of a value- added product. By reducing synthetic media and utilizing MOP, a greener bioprocess can be achieved, and BC’s applicability can be expanded.
- Inactivation of Staphylococcus aureus by antimicrobial photodynamic therapy using 1,9-Dimethyl-Methylene Blue: in vitro and in vivo studiesPublication . Brito Júnior, Anildo Alves de; Crugeira, Pedro; Barbosa, Andressa Vollono; Costa, Wellington Luis Reis; Cangussu, Maria Cristina Teixeira; Oliveira, Susana Carla Pires Sampaio de; Pinheiro, Antônio Luiz Barbosa; Melo, Amanda Inês Vieira de; Pinheiro, Antônio Luiz Barbosa; Azevedo, Juliana MonteiroThe efficiency of antibiotics in terms of their bacterial inhibition is well known. However, studies show that its overuse, underuse, and misuse induce antimicrobial resistance, promoting the need to work with alternative methods. In this sense, antimicrobial photodynamic therapy (aPDT) is a promising selective method demonstrating excellent response. This study aimed to evaluate the antimicrobial action promoted in Staphylococcus aureus using 1,9 dimethyl methylene blue dye (DMMB) combined with red LED (λ 630 ± 20 nm, CW, 125 mW, 12 J/ cm², 192 s) in planktonic culture and rats skin wounds contaminated with staphylococcal bacteria. The experimental in vitro and in vivo groups were Control, LED, DMMB, and LED + DMMB; after aPDT, the triplicate samples for each dilution were incubated for 24 h, and the number of bacteria was determined by counting the colony-forming units, and the logarithm (CFU/mL log). Based on in vitro data obtained, the LED + DMMB group, when compared to the Control, showed a reduction in microbial load of 99.943% (p < 0.0001), with decimal reduction (RD = 3). Whereas in vivo results, the same comparing groups demonstrated a reduc- tion in microbial load, reaching 99.994% (RD = 4). In this research, the aPDT was a unique treatment, and it is possible to repeat it to obtain higher microbial reduction, providing an alternative therapeutic that can be clinically validated to combat infections caused by S. aureus.
- Influence of Produced Water and Light Irradiation on the Composition of Exopolysaccharide Produced by L. amnigena Evaluated by Raman SpectroscopyPublication . Silva, Anna Paula Lima Teixeira da; Soares, Luiz Guilherme Pinheiro; Gulberg, Lars Duarte; Crugeira, Pedro; Almeida, Paulo Fernando de; Fernandes, Adjaci Uchoa; Silveira, Landulfo; Pinheiro, Antonio Luiz BarbosaThis study aimed to compare the changes in the composition of the exopolysaccharide (EPS) produced by Lelliottia amnigena in culture medium containing distilled water (DW) and dialyzed produced water (DPW) irradiated by either Laser (λ660 nm, 8.0 J/cm2) or LED (λ630 nm, 12.0 J/cm2) during bacterial growth using Raman spectroscopy at 1064 nm. The cultures of L. amnigena were irradiated at 9‐ and 12‐h, and the EPS obtained from different production protocols were analyzed dehydrated. Raman spectra showed peaks assigned to saccharides from EPS polymer, and principal component analysis revealed differences in the composition of the EPS produced depending on the water used in production and the light source used for irradiation. Remarkably, the presence of acyl groups (acetyl and pyruvyl) in the mannose residues at the group DW and mannose without evidence of acetyl in the irradiated groups; the irradiated groups also presented evidence of carboxylate (succinyl).
- Photoinactivation of sulfate-reducing bacteria using 1,9-dimethyl-methylene blue – DMMB and laser lightPublication . Santos, Gustavo Vital dos; Moura, Hesrom Fernandes Serra; Pedro Jorge Louro Crugeira; Anna Paula Lima Teixeira da Silva; Isabele Cardoso Vieira de Castro; Wellington Luís Reis Costa; Paulo Fernando de Almeida; Antonio Luiz Barbosa Pinheiro; Crugeira, PedroAnnually, the oil and gas industry faces equipment losses and product quality degradation due to the presence of sulfate-reducing bacteria (SRB). Given the negative impact of SRB, this study evaluates the use of photoinactivation (PI) with zinc chloride double salt of 1,9-Dimethyl-Methylene Blue (DMMB) as a photosensitizer (PS) in varying concentrations and combined with Laser light at different exposures in an SRB consortium. For culture growth, a modified Postgate C medium (without ferrous sulfate) was used, and cell quantification was performed on 100 μL aliquots of the consortium, read on a spectrophotometer (λ600 nm) in an oxygen- and light-free environment at room temperature. Statistical analyses included two-way ANOVA and ANOVA with interaction to separately and jointly evaluate the effects of PS and light in PI. Results indicated microbial activity in all groups, with an antimicrobial inhibition rate exceeding 50 % (p < 0.05) for concentrations above 1.5 μg/mL of DMMB. PI efficacy significantly depended on DMMB concentration and light density, achieving a 70.58 % (55.73–70.58, with a mean of 66.71 %) reduction (p < 0.05) with 1.5 μg/mL of DMMB and a 70.15 % (65–70.15, with a mean of 68.21 %) reduction with 2.0 μg/mL at an intensity of 21.6 J/cm2. In conclusion, PI presents a promising alternative to biocides in the oil and gas industry, offering easy application, avoiding bacterial resistance, being environmentally safe, and compatible with other SRB population control techniques.