Percorrer por autor "Silva, Anna Paula Lima Teixeira da"
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- 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; Crugeira, Pedro Jorge Louro; Silva, Anna Paula Lima Teixeira da; Castro, Isabele Cardoso Vieira de; Costa, Wellington Luís Reis; Almeida, Paulo Fernando de; Pinheiro, Antonio Luiz BarbosaAnnually, 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 lightfree 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.