Increase in desulfurization activity of Rhodococcus erythropolis KA2-5-1 using ethanol feeding

Effects of nicotinamide and riboflavin on the biodesulfurization activity of dibenzothiophene by Rhodococcus erythropolis USTB-03

“…Addition of nicotinamide or riboflavin was found to obviously promote SA of R. erythropolis USTB-03 (Figs.2c and 3c). The current maximum SA of 159.0 mmol 2HBP/(kg dry cells·h), in comparison with 135.0 mmol 2HBP/(kg dry cells·h) in our previous report (Yan et al, 2000(Yan et al, ), was et al, 2000, was achieved when R. erythropolis USTB-03 was grown on both nicotinamide of 5 mmol and riboflavin of 25 µmol (Fig.4c). In addition to the enhancement of SA by genetic engineering was widely studied (Ishii et al, 2000;Borole et al, 2002;Nomura et al, 2005), it could also be achieved by the metabolic supplementation using nicotinamide and riboflavin in the culture medium.…”

“…Although chemical-physical processes can be used to remove inorganic sulfur from crude fuels, organic sulfur in dibenzothiophene (DBT), a widely used model of organic sulfur compound, remains in petroleum and coal even after these processes (Gray et al, 1996). To overcome this problem, some promising bacterial strains are identified to remove sulfur from DBT through the sulfur-specific pathway, which is capable of obtaining nutritional sulfur from DBT and producing 2-hydroxybiphenyl (2HBP) as the final product without causing oxidative loss of fuel carbon, which is the most efficient means for the desulfurization of DBT (Yan et al, 2000;Furuya et al, 2001;Kirimura et al, 2002;Li et al, 2005;Ishii et al, 2005;Yang and Marison, 2005;Gunam et al, 2006).…”

“…Subsequently, a second flavomonooxygenase (Dsz A) is responsible for the conversion of DBTO 2 to 2-2 -hydroxyphenyl benzene sulfinate (HPBS), and Dsz B, a desulfinase, catalyzes the final step involving the conversion of HPBS to 2HBP (Yan et al, 2000). Reduced form of flavin mononucleotide (FMNH2) is required for the activities of both Dsz C and A, and a enzyme flavin reductase (Dsz D) is needed for the conversion of FMN to FMNH2 using NADH as the reducing agent (Lei and Tu, 1996;Matsubara et al, 2001;Gray and Mrachko, 2003).…”

“…If microorganisms are to be used as non-growing biocatalysts, they need to be grown in a separate process and SA of biodesulfurization is a crucial indicator for efficiency. Previously, high SA of 135.5 mmol 2HBP/(kg dry cells·h) and cell concentration of 37 g dry cells/L of Rhodococcus erythropolis KA2-5-1 were found in a fed-batch fermentation culture, when ethanol as the sole carbon and energy source was maintained at 1.0 g/L under the control of a semiconductor gas sensor (Yan et al, 2000). The genes for biodesulfurization enzymes have been cloned, sequenced and engineered from a variety of microorganisms (Ishii et al, 2000;Borole et al, 2002;Nomura et al, 2005); however, little information was provided on how to increase SA of biodesulfurization through the metabolic promotion of FMNH2 and the production of reduced form of nicotinamide-adenine dinucleotide (NADH) .…”

H2S removal and bacterial structure along a full-scale biofilter bed packed with polyurethane foam in a landfill site

“…Pusillimonas noertemannii was identified from aerobic activated sludge for phenols and thiocyanate removal and the bacterial community in a full-scale biofilter treating pig house exhaust air (Felföldi et al, 2010;Kristiansen et al, 2011). Rhodococcus erythropolis was found to desulfurize dibenzothiophene in a C-S bond targeting manner and form sulfite as final products (Yan et al, 2000). The introduction of odorants into the biofilter shifted the structure of the existing microbial populations toward a specific culture that could metabolize the target substrates.…”