A Novel Moisture-Absorbing Extracellular Polysaccharide from Rhodococcus rhodochrous SM-1.

Abstract

An extracellular polysaccharide (EPS) prepared from SM-1, a mucoidal mutant of Rhodococcus rhodochrous ATCC 12674 was found to absorb and retain moisture in both dry and high-temperature environments. The EPS absorbed more than 120% and 17% of its weight in moisture under the conditions of 32% and 11% relative humidity, respectively, representing much higher absorption than that of known moisture absorbents such as silica gel, glycerol, and hyaluronic acid. The SM-1 EPS is an acidic polysaccharide containing D-galactose, D-glucose, L-fucose, and D-glucuronic acid at a molar ratio of 6: 3: 2: 4. In addition, 1.2% (W/W) stearic acid, 2.3% (W/W) palmitic acid, and 10.3% (W/W) pyruvic acid were also contained in the SM-1 EPS. These evidences indicate that the SM-1 EPS is a novel moistureabsorbing biopolymer.

Mucilaginibacter kameinonensis sp., nov., isolated from garden soil

“…It has been reported that some bacterial strains belonging to the genus Rhodococcus produce extracellular polysaccharides (EPS), including fatty acids containing EPS, and that these EPS have a variety of functions, including protection of bacterial cells from the toxicity of hydrocarbons (Aizawa et al, 2005;Iwabuchi et al, 2000), emulsification, moisture absorption (Urai et al, 2002(Urai et al, , 2004 and stimulation of degradation of polyaromatic hydrocarbons (PAH) spilled in marine environments, the latter probably occurring via stimulation of marine PAHassimilating bacteria (Iwabuchi et al, 2002). These EPS are acidic, high-molecular-mass polysaccharides containing uronic acids (Urai et al, 2006a(Urai et al, , b, 2007a.…”

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

“…Pyruvic acid content was enzymatically determined with an F-kit Pyruvic acid (J. K. International Co., Tokyo, Japan), as described by the supplier, after hydrolysis with 2% TFA at 100°C for 120 min. Fatty acid analyses were performed as described previously 10) . Gel filtration column chromatography for native 33 EPS was performed by using Sephacryl S1000 (850 mm × 15 mmφ; Amersham Biosciences UK Limited, Buckinghamshire, UK) as resin, 1 mM Tris-HCl (pH8.0) containing 0.1 M NaCl as eluent, and Dextran T2000 (Amersham Biosciences UK Limited, Buckinghamshire, UK) as size marker.…”

“…33 (33 EPS) and by Rhodococcus rhodochrous S-2 (S-2 EPS) were removed from the cells by shaking and partially purified by enzymatic treatments, phenol/chloroform treatment and ethanol precipitation as described by Urai et al 10) These partially purified EPS were further purified by DEAE-Toyopearl 650M column chromatography as described by Urai et al…”

An Anionic Polymer Incorporating Low Amounts of Hydrophobic Residues Is a Multifunctional Surfactant. Part 1: Emulsifying, Thickening,Moisture-Absorption and Moisture-Retention Abilities of a FattyAcid-Containing Anionic Polysaccharide

“…The moisture absorption and retention capacities were measured as described by Urai et al [1]. Briefly, constant relative humidity conditions were established at 37˚C.…”

“…We have been studying the function and structure of extracellular polysaccharides (EPS) produced by several Rhodococcus species [1]- [8], and we demonstrated the potential commercial application of an EPS, prepared from a mucoidal mutant, SM-1, of Rhodococcus rhodochrous ATCC 12674 (SM-1 EPS), as an emulsifier and in moisture-absorbent and moisture-retention materials [1]. SM-1 EPS was found to absorb and retain moisture in both dry and high-temperature environments at a much greater extent than known moisture absorbents or retentioners such as silica gel, glycerol, and hyaluronic acid.…”