Pseudomonas resinovorans SPR1, a newly isolated strain with potential of transforming eugenol to vanillin and vanillic acid

In this study a novel strain was isolated with the capability to grow on eugenol as a source of carbon and energy. This strain was identified as Pseudomonas resinovorans (GenBank accession no. HQ198585) based on phenotypic characterization and phylogenetic analysis of 16S rDNA gene. The intermediates coniferyl alcohol, coniferyl aldehyde, ferulic acid, vanillin and vanillic acid were detected in the culture supernatant during eugenol biotransformation with this strain. The products were confirmed by thin layer chromatography (TLC), high performance liquid chromatography (HPLC) and spectral data achieved from UV-vis, FTIR and mass spectroscopy. Using eugenol as substrate and resting cells of P. resinovorans SPR1, which were harvested at the end of the exponential growth phase, without further optimization 0.24 g/L vanillin (molar yield of 10%) and 1.1g/L vanillic acid (molar yield of 44%) were produced after 30 h and 60 h biotransformation, respectively. The current work gives the first evidence for the eugenol biotransformation by P. resinovorans.     

Candida galli Strain PGO6: A Novel Isolated Yeast Strain Capable of Transformation of Isoeugenol into Vanillin and Vanillic Acid

Candida galli strain PGO6 isolated from oil-contaminated water is the first isolated yeast strain which is capable to form vanillin and vanillic acid during isoeugenol biotransformation. The products were confirmed by thin-layer chromatography (TLC), changes in the UV absorption pattern and high-performance liquid chromatography (HPLC). The phenotypic and physiochemical characteristics as well as molecular phylogenetic analysis based on amplification the ITS1-5.8S-ITS2 rDNA regions indicated the isolated strain PGO6 was identified as C. galli (GenBank accession number HM641231). Resting cells of C. galli PGO6 from the late-exponential of growth phase were used as biocatalysts for the biotransformation of isoeugenol. The optimal molar conversion of vanillin (48%) and vanillic acid (19%) was obtained after a 30 h incubation using 0.1% (v/v) of isoeugenol and 6 mg of dry weight of cells per ml without further optimization. Under these conditions, the total amount of vanillin and vanillic acid was 583 mg l(-1). Further biotransformation was carried out using 0.5% (v/v) of isoeugenol under the resting cells conditions, yielding a vanillin concentration of 1.12 g l(-1) (molar yield 25.7%) after 60 h incubation. This study brings the first evidence for biotransformation of isoeugenol to vanillin and vanillic acid by a yeast strain.     

Isolation and initial characterization of the tellurite reducing moderately halophilic bacterium, Salinicoccus sp. strain QW6

Among the 49 strains of moderately halophilic bacteria isolated from the salty environments of Iran, a Gram-positive coccus designated as strain QW6 showed high capacity in the removal of toxic oxyanions of tellurium in a wide range of culture medium factors including pH (5.5-10.5), temperature (25-45 degrees C), various salts including NaCl, KCl, and Na(2)SO(4) (0.5-4M), selenooxyanions (2-10mM), and at different concentrations of potassium tellurite (0.5-1mM) under aerobic condition. Phenotypic characterization and phylogenetic analyses based on 16S rDNA sequence comparisons indicated that this strain was a member of the genus Salinicoccus. The maximum tellurite removal was exhibited in 1.5M NaCl at 35 degrees C, while the activity reduced by 53% and 47% at 25 and 45 degrees C, respectively. The optimum pH for removal activity was shown to be 7.5, with 90% and 83% reduced removal capacities at the two extreme values of 5.5 and 10, respectively. The impact of different concentrations of selenooxyanions (2-10mM) on tellurite removal by strain QW6 was evaluated. The ability of strain QW6 in the removal of tellurite in the presence of 6mM selenite increased by 25%. The concentration of toxic potassium tellurite in the supernatant of the bacterial culture medium decreased by 99% (from 0.5 to 0.005mM) after 6 days and the color of the medium changed to black due to the formation of less toxic elemental tellurium.