Relationship between Extracellular Polysaccharide and Benzene Tolerance of Rhodococcus sp. 33

Abstract

Benzene is one of the most toxic and prevailing environmental pollutants. Rhodococcus sp. 33 can tolerate and efficiently degrade various concentrations of benzene. Under either resting or growth conditions, rough mutant strains derived from strain 33 were more sensitive to benzene than the mucoidal parent strain. The rough strains did not produce extracellular polysaccharides (EPS), whereas the parental strain 33 did so in large quantity (33 EPS). By the addition of 33 EPS to the rough strains, both the survival and growth of the rough strains in media containing benzene were improved. The 33 EPS was found to be an acidic polysaccharide containing D-galactose, D-glucose, D-mannose, D-glucuronic acid, and pyruvic acid at a molar ratio of 1: 1: 1: 1: 1. These data suggest that the 33 EPS plays an important role in the benzene tolerance in Rhodococcus sp. 33, especially helping the cells to survive an initial challenge with benzene.

The structure of the exocellular polysaccharide produced by Rhodococcus sp. RHA1

“…However, the rough strains showed restored growth after the addition of EPS produced by the mucoid strain. 14,16 Furthermore, it was shown that the addition of EPS produced by R. rhodochrous strain S-2 to oil-contaminated seawater, resulted in oil emulsification and increased degradation of polyaromatic hydrocarbons (PAH) and the promotion of PAH indigenous degrading marine bacteria. 13 Thus, rhodococcal EPS plays a role, not only in cell viability and survival, but also in biodegradation of reluctant aromatic compounds.…”

Burkholderia bannensis sp. nov., an acid-neutralizing bacterium isolated from torpedo grass (Panicum repens) growing in highly acidic swamps

“…The major fatty acids of both strains grown on 1/10 TS agar plates containing 1 % glucose (pH 5.0) at 28 u C for 3 days were C 16 : 0 , C 17 : 0 cyclo and C 18 : 1 v7c (Supplementary Table S2); similar patterns were obtained from cells of the type strains of closely related species. Isoprenoid quinones were prepared as described previously (Tamura et al, 1994) and analysed by using a Quattro premier MS coupled to an Acuity UPLC (UPLC/MS/MS; Waters) as described by Aizawa et al (2010a). The major isoprenoid quinone of the strains was Q-8, as in the case of other species of the genus Burkholderia (Yamada et al, 1982;Zhang et al, 2000;Yang et al, 2006;Valverde et al, 2006;Aizawa et al, 2010b, c).…”

Analysis of Benzene-Induced Effects onRhodococcussp. 33 Reveals that Constitutive Processes Play a Major Role in Conferring Tolerance

“…Previous work on the isolated polymer by Aizawa et al [25] showed it to exhibit surfactant properties, similarly to polymers isolated from other rhodococci [26,27,28,29], and that addition of the polymer to rough mutant strains (i.e., lacking in their production of the polymer) increased both their survival and growth in media containing benzene. Interestingly, the pyruvic acid moiety of the polymer was suggested as a key factor in tolerance [25]. Collectively, since the mutant strains generated in the present study were found to have either partially or completely lost their ability to express cell surface polymer, their susceptibilities to benzene appear to be contributed by their lack of polymer expression.…”

“…Polyanionic biopolymers can have useful commercial applications, such as in the sequestration of cationic dyes and heavy metals from contaminated effluents and wastewaters [22,23,24]. Previous work on the isolated polymer by Aizawa et al [25] showed it to exhibit surfactant properties, similarly to polymers isolated from other rhodococci [26,27,28,29], and that addition of the polymer to rough mutant strains (i.e., lacking in their production of the polymer) increased both their survival and growth in media containing benzene. Interestingly, the pyruvic acid moiety of the polymer was suggested as a key factor in tolerance [25].…”