Extracellular accumulation of mono- and di-succinoyl trehalose lipids by a strain of Rhodococcus erythropolis grown on n-alkanes.

Abstract

A bacterium, strain SD-74, which was isolated from soil under alkaline conditions, was found to abundantly produce acidic exolipids from /i-alkanes. The strain proved to be alkali-resistant rather than alkalophilic and was identified as Rhodococcus erythropolis. The acidic exolipids (15 g) were isolated from culture broth (1 1) containing /i-hexadecane as the sole carbon source and were found to be composed of two new succinoyl trehalose lipids (STL-1 and STL-2). After purification, STL-1 showed mp 169 to 171 C and [a]2D°+92.3°(c=0.6, CHC13/ MeOH=2:l), and STL-2 mp 161 to 163 C and [a]2D°+75.0°(c=0.6, CHCl3/MeOH=2:1). On the basis of the results of chemical degradation and methylation, STL-1 and STL-2 were concluded to be 2,3,4,2'-di-0-succinoyl-di-0-alkanoyl-a,a-trehalose and 2,3,4-mono-O-succinoyl-di-Oalkanoyl-a,a-trehalose, respectively.

Structural Characterization and Surface-Active Properties of a Succinoyl Trehalose Lipid Produced by Rhodococcus sp. SD-74

“…The molecular weight of the major constituent of the purified STL-1 was 1042.2 as determined by the main peak ([M+Na] + ) of MALDI-TOF/MS analysis. This clearly indicates that the major constituent is trehalose lipid having two succinoyl and hexadecanoyl residues as previously reported 10) . We further investigated the fatty acid profile of the purified STL-1 by the GC-MS method (…”

“…Rhodococcus sp. SD-74 isolated as a STL producer 10) was exclusively used in this study. Stock culture were cultivated for 3 days at 30 on a PMY agar medium containing 1% (wt/v) glycerol, 0.5% polypeptone, 0.3% yeast extract, 0.3% malt extract, 0.1% KH 2 PO 4 , 0.1% K 2 HPO 4 , and 1.5% agar.…”

“…The extracts were analyzed by TLC on silica plates with chloroform/methanol/acetic acid/water (65:15:2:2, by vol.). The compounds on the plates were located by charring at 110 for 5 min after spraying an anthrone/sulfuric acid reagent as reported previously 10) . The extracts were concentrated under reduced pressure and dissolved in chloroform/methanol (1:1, v/v) and then purified by silica-gel (Wako-gel C-200) column chromatography using a gradient elution of chloroform/methanol (10:0 7:3, v/v) mixtures as solvent systems.…”

“…SD-74 grown on n-hexadecane mainly produces two glycolipids, namely STL-1 and STL-2 6,10) . On TLC, the ethyl acetate extracts gave three spots of glycolipids ( ).…”

Analysis of Genes for Succinoyl Trehalose Lipid Production and Increasing Production in Rhodococcus sp. Strain SD-74

“…These STLs are also recovered via precipitation (12). This bacterial strain primarily produces two types of STL homologues, STL-1 and STL-2, in addition to other minor components (13). Interestingly, the hydrophobic acyl groups of all STLs have the same carbon chain length as the n-alkane used as the substrate.…”