Bioremediation technology is one of the most profitable and sustainable strategies for remediating soils contaminated with hydrocarbons. This study focuses on assessing the influence of biostimulation and bioaugmentation with Pseudomonas fluorescens to contribute to the removal of total petroleum hydrocarbons (TPHs) of a soil. Laboratory studies were carried out (measurements of emitted CO₂, surface tension, and residual TPH) to select the best bioaugmentation and biostimulation treatment. The sources of C, N, and P were glucose–yeast extract, NH₄Cl–NaNO₃, and K₂HPO₄–K₃PO₄, respectively. The effect of culture conditions on the reduction of TPH and respiratory activity was evaluated through a factorial design, 2³, in a solid culture system. After 80 days of incubation, it was observed that treatments of yeast extract–NH₄Cl–K₂HPO₄ (Y4) and glucose–NaNO₃–K₃PO₄ (Y5) presented a higher level of TPH removal (20.91% and 20.00% degradation of TPH, respectively). Biostimulation favors the production of biosurfactants, indirectly measured by the change in surface tension in the soil extracts. The treatments Y4 and Y5 showed a lower change value of the surface tension (23.15 and 23.30 mN·m⁻¹ at 25 °C). A positive correlation was determined between the change in surface tension and the removal of TPH; hence there was a contribution of the biosurfactants produced to the removal of hydrocarbons.

This study employed the use of 16S rRNA gene sequence analysis to identify three of four native bacterial strains isolated from crude oil-contaminated site in Poza Rica, Veracruz, Mexico. The identified bacteria were Ochrobactrum intermedium, Pandoraea pnomenusa and Ochrobactrum sp., but SA2-09 strain was not identified. The ability of the isolates to degrade polycyclic aromatic hydrocarbons (PAHs) was evaluated at 31.61 and 54.52 mg/kg PAHs in soil, when used as crude oil in soil microcosm during 80 days of incubation at 30°C. The results demonstrated that O. intermedium biodegraded many PAHs, including the high molecular weight (HMW) PAHs fluoranthene (100% equivalent 0.24 mg/kg), benzo [b] fluoranthene (81.8% equal 0.18 mg/kg), Benzo[a]pyrene (87.0%, 0.20 mg/kg) and Benzo[g,h,i]perylene (52.7%, 0.39 mg/kg). P. pnomenusa had a degradation profile of HMW PAHs, which was similar to O. intermedium, while Ochrobactrum sp. and the strain SA-09 exhibited lower degradation rates of HMW.

En este documento se comenta el informe Captura de carbono en los suelos para un mejor manejo de la tierra[1] , en el que se analiza el potencial de los suelos agrícolas, forestales y de pastoreo para actuar como sumideros de carbono. Primero se revisa la dinámica actual de este elemento en los suelos y los factores que la regulan; posteriormente se proponen medidas de manejo para cada uso de suelo y finalmente se hace un análisis de las alternativas propuestas.

Introduction: Multidrug-resistant (MDR) pathogenic bacteria in seafood, especially shrimp and octopus, are significant public health concerns and are able to be transmitted to humans in foodstuffs, particularly when they are of animal origin. The present study was conducted to measure the antimicrobial susceptibility patterns and prevalence of Salmonella isolates obtained from octopus and shrimp in San Francisco de Campeche, Mexico. Methods: Two hundred shrimp and octopus samples (one hundred each) were collected from the municipal market, and each sample consisted of 100 g. The present study used conventional methods to identify and isolate Salmonella, with the disk-diffusion method used to screen all isolates for sensitivity to 12 antibiotics. Results: The prevalence of Salmonella was found to be 56% and 45% in shrimp and octopus, respectively. The high levels of Salmonella observed in the municipal market sampled by the present study reveal poor sanitary conditions in the processing and transport of the products of interest and those handling them at the point of sale. All the Salmonella strains were resistant to at least three antimicrobial classes. All shrimp isolates (100%) presented susceptibility to chloramphenicol and the majority (88%) presented sensitivity to ciprofloxacin, while the strains isolated in the octopus individuals sampled presented sensitivity to both the foregoing antibiotics (74% and 90%, respectively). Conclusion: Based on the high prevalence in the samples analyzed, our results suggest that shrimp and octopus could be involved in Salmonella infections in the population.