Biodesulfurization of dibenzothiophene and gas oil using a bioreactor containing a catalytic bed with Rhodococcus rhodochrous immobilized on silica

Abstract

Biodesulfurization (BDS) in a bioreactor packed with a catalytic bed of silica containing immobilized Rhodococcus rhodochrous was studied. Various bed lengths and support particle sizes were evaluated for BDS of dibenzothiophene (DBT) and gas oil. The sulfur-containing substrates were introduced separately into the bioreactor at different feed flows. Higher removal of sulfur from DBT and gas oil was achieved with a long bed, lower substrate flow, and larger sizes of immobilization particles. The packed bed bioreactor containing metabolic active cells was recycled and maintained BDS activity.

Metaproteomic analysis of atmospheric aerosol samples

“…The identified proteins mainly originated from plants (68 % in TSP, 31 % in fine particles), microorganisms (fungi, bacteria, Amoebozoa, etc., 25 % in TSP, 50 % in fine particles) and animals (7 % in TSP, 19 % in fine particles), which is in line with the major categories of PBAP [1]. Notably, in the coarse particle sample one protein has been assigned to a bacterium ( Rhodococcus rhodochrous ) [47], which is used as a soil inoculant in agriculture, while potential assignments of proteins identified in the fine particle and TSP sample to the kingdom of bacteria were not unambiguous on the kingdom level.…”

A new functional biofilm biocatalyst for the simultaneous removal of dibenzothiophene and quinoline using Rhodococcus rhodochrous and curli amyloid overproducer mutants derived from Cobetia sp. strain MM1IDA2H-1

“…The bacterial strains and their relevant genotype and phenotype are listed in Table 1 . For sulfur-containing heterocycle metabolism, Medium A, supplemented with sodium succinate (30 mM) and citrate (0.1% w/v) as energy and carbon sources, respectively, or DBT (0.1 mM) (Merck) dissolved in isooctane (IOA) as the sulfur source, was used for growth [ 17 , 18 ]. For N-heterocycle metabolism with Cobetia sp.…”

“…For this, cells were collected from 24 h cultures of each strain by centrifugation at 4000 ☓ g for 5 min at 4 °C. The pellet was suspended in 1000 mL of 0.85% w/v NaCl at pH 5.5 and circulated through the SiO 2 of packed bed column with a total volume of 94.2 mL (2 cm diam., 30 cm length) in a downward direction at 10 mL min −1 for 72 h [ 18 ]. The number of immobilized cells was measured by loss of turbidity of the initial cell suspension at 600 nm [ 18 ].…”

“…For the reaction step, packed bed columns with respective biofilms were used as bioreactors for removal of QN and the simultaneous removal of DBT and QN. Each glass column was filled with SiO 2 particles with a bed height of 15 cm and particle sizes in the range 3.35–5.6 mm [ 18 ]. For reactions QN solution (0.77 mM) with nitrogen-free Medium 9 or a mixture of DBT (6.23 mM) and QN solution (0.77 mM) with a mixture of nitrogen-free Medium 9 and sulphur-free Medium A were fed continuously into the bioreactor in a downward direction at 0.9 mL min −1 using a peristaltic pump over two hours.…”

Kinetic Analysis for Biodesulfurization of Dibenzothiophene using R. rhodochrous Adsorbed on Silica

“…However, the main disadvantage of BDS process is the limited access of the microorganisms to the organic substrates, due to the low bioavailability of sulfur compounds in the bacterial aqueous medium [9]. In this context, immobilized bacterial cells [10][11][12][13][14] and the use of surfactants [15][16][17] constitute an improvement in the field of desulfurization. BDS operation with microbial cells immobilized either, onto the surface of adsorbent material [13,14] or entrapped into a polymeric matrix [12,18] has gained special interest during the last decade.…”