Browsing by Author "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.
- 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).