Teixeira Alexandra V, Paixão Susana M, da Silva Teresa Lopes, Alves Luís
LNEG-Instituto Nacional de Energia e Geologia IP, Unidade de Bioenergia, Estrada do Paço do Lumiar, 22, 1649-038, Lisbon, Portugal.
Appl Biochem Biotechnol. 2014 Jun;173(4):870-82. doi: 10.1007/s12010-014-0902-6. Epub 2014 Apr 13.
The viability of bacteria plays a critical role in the enhancement of fossil fuels biodesulfurization efficiency since cells are exposed to toxic compounds such as 2-hydroxybiphenyl (2-HBP), the end product of dibenzothiophene (DBT) biodesulfurization. The goal of this work was to study the influence of the carbon source on the resistance of Gordonia alkanivorans strain 1B to 2-HBP. The physiological response of this bacterium, pre-grown in glucose or fructose, to 2-HBP was evaluated using two approaches: a growth inhibition toxicity test and flow cytometry. The results obtained from the growth inhibition bioassays showed that the carbon source has an influence on the sensitivity of strain 1B growing cells to 2-HBP. The highest IC50 value was obtained for the assay using fructose as carbon source in both inoculum growth and test medium (IC50-48 h = 0.464 mM). Relatively to the evaluation of 2-HBP effect on the physiological state of resting cells by flow cytometry, the results showed that concentrations of 2-HBP >1 mM generated significant loss of cell viability. The higher the 2-HBP concentration, the higher the toxicity effect on cells and the faster the loss of cell viability. In overall, the flow cytometry results highlighted that strain 1B resting cells grown in glucose-SO4 or glucose-DBT are physiologically less resistant to 2-HBP than resting cells grown in fructose-SO4 or fructose-DBT, respectively.
细菌的生存能力在提高化石燃料生物脱硫效率方面起着关键作用，因为细胞会接触到有毒化合物，如二苯并噻吩（DBT）生物脱硫的终产物2-羟基联苯（2-HBP）。这项工作的目标是研究碳源对食烷戈登氏菌1B菌株对2-HBP抗性的影响。使用两种方法评估了这种在葡萄糖或果糖中预培养的细菌对2-HBP的生理反应：生长抑制毒性试验和流式细胞术。从生长抑制生物测定中获得的结果表明，碳源对1B菌株生长细胞对2-HBP的敏感性有影响。在接种物生长和测试培养基中使用果糖作为碳源的试验中获得了最高的IC50值（IC50-48小时 = 0.464 mM）。相对于通过流式细胞术评估2-HBP对静息细胞生理状态的影响，结果表明，2-HBP浓度>1 mM会导致细胞活力显著丧失。2-HBP浓度越高，对细胞的毒性作用越大，细胞活力丧失越快。总体而言，流式细胞术结果突出表明，在葡萄糖-SO4或葡萄糖-DBT中生长的1B菌株静息细胞在生理上对2-HBP的抗性低于分别在果糖-SO4或果糖-DBT中生长的静息细胞。
