Response Surface Methodology Optimization of Dibenzothiophene Biodesulfurization in Model Oil by Nanomagnet Immobilized Rhodococcus Erythropolis R1

Abstract

Abstract:Rhodococcus erythropolis R1 is a capable strain in bioconversion of dibenzothiophene (DBT) to 2-hydroxybiphenyl (2-HBP) in oil model. In order to prevent the contamination of biodesulfurization (BDS) products by free cells, microbial cells were immobilized using different materials such as magnetic Fe 3 O 4 nanoparticles (NPs). In this study, magnetic NPs were produced by two different procedures and their characteristics were determined via transmission electron microscopy (TEM) and X-ray diffraction (XRD). Also, binding of NPs on the cell surface was studied and better NPs were used for cells immobilization. Both NPs were crystallized and less than 10nm. The BDS by immobilized cells was carried out in biphasic system, and media conditions were optimized statistically by response surface methodology (RSM). The DBT concentration, temperature and interaction between them had statistically significant effects on 2-HBP production by nanomagnet immobilized cells. The optimum DBT concentration, temperature and pH for 2-HBP production by immobilized R. erythropolis R1 were obtained at 6.76mM, 29.63 °C and 6.84 respectively by HPLC analysis.

Characterization of Immobilized Magnetic Fe3O4 Nanoparticles on Raoultella Ornithinolytica sp. and Its Application for Azo Dye Removal

“…Chang et al [ 51 ] found that the high rate of degradation at optimal pH is linked to the transfer of dye molecules through the cell membrane, which is the rate-limiting stage in degradation. Changes in pH can influence not just the shape of an enzyme, but also the shape or charge characteristics of the substrate, which prevents the substrate from binding to the active site or undergoing catalysis, according to Etemadifar et al [ 52 ]. Rajeswari et al [ 53 ] discovered that the maximal removal of reactive dyes by employing Lysinibacillus sphaericus RSV-1 was 94.37% and 91.99% at pH 7 and 9, respectively, after 36 h of incubation.…”

Investigation of Desulfurization Activity, Reusability, and Viability of Magnetite Coated Bacterial Cells

“…In the previous studies, magnetite nanoparticles were immobilized on the surface of Pseudomans delafieldii , Rhodococcus erythropolis LSSE8-1, and Rhodococcus erythropolis IGTS8 bacterial cells, where the desulfurization activity and reusability of magnetite coated bacteria were evaluated (19, 20, 22, 23). On the other hand, in our prior study, we coated R. erythropolis IGTS8 and R. erythropolis FMF with glycine-modified magnetite nanoparticles and investigated the effect of magnetite nanoparticles on the desulfurization activity of bacterial strains (24).…”