No abstract

BACKGROUND: Wastes generated in production of caprolactam (2‐oxohexamethylenimine, ε‐caprolactam) and caprolactam‐based polymers contain the unreacted monomer and its low‐molecular linear and cyclic oligomers. Application of microorganisms for biological treatment of caprolactam‐ and oligomer‐containing wastes can become an alternative to existing waste utilization methods. This work investigated the transformation of caprolactam low‐molecular linear oligomers by caprolactam‐degrading bacteria bearing degradative plasmids (CAP plasmids).RESULTS Based on mass spectrometry data, a scheme for the biotransformation of caprolactam linear oligomers is proposed. Oxidative transamination to corresponding dicarboxylic acids can be one of the transformation mechanisms. Oxidative transamination occurs due to a broad substrate specificity of the caprolactam catabolism key enzymes 2‐oxoglutarate‐6‐aminohexanoate transaminase (EC.2.6.1‐) and 6‐oxohexanoate dehydrogenase (EC.1.2.1.63) whose synthesis is determined by CAP plasmids. Incubation of cells 2.0–3.0 × 109 CFU mL−1 of strains with various plasmid‐bacterial host combinations in 2 mmol L−1 solution of a dimer for 96 h leads to its almost complete transformation to a corresponding dicarboxylic acid. The dynamics of the process largely depends on the host strain.CONCLUSION: Deamination of oligomers in their transformation by the enzyme systems of caprolactam‐degrading bacteria can substitute the chemical methods of pretreating caprolactam‐ and oligomer‐containing wastes for their subsequent biological purification. Copyright © 2012 Society of Chemical Industry

No abstract

No abstract

A non-pigmented, motile, Gram-negative bacterium designated H 17(T) was isolated from a seawater sample collected in Port Phillip Bay (the Tasman Sea, Pacific Ocean). The new organism displayed optimal growth between 4 and 37 °C, was found to be neutrophilic and slightly halophilic, tolerating salt water environments up to 10 % NaCl. Strain H 17(T) was found to be able to degrade starch and Tween 80 but unable to degrade gelatin or agar. Phosphatidylglycerol (27.7 %) and phosphatidylethanolamine (72.3 %) were found to be the only associated phospholipids. The major fatty acids identified are typical for the genus Alteromonas and include C16:0, C16:1ω7, C17:1ω8 and C18:1ω7. The G+C content of the DNA was found to be 43.4 mol%. A phylogenetic study, based on the 16S rRNA gene sequence analysis and Multilocus Phylogenetic Analysis, clearly indicated that strain H 17(T) belongs to the genus Alteromonas. The DNA-DNA relatedness between strain H 17(T) and the validly named Alteromonas species was between 30.7 and 46.4 mol%. Based on these results, a new species, Alteromonas australica, is proposed. The type strain is H 17(T) (= KMM 6016(T) = CIP 109921(T)).

The dependence of EMF, current and voltage at a fixed load, and the fuel cell inner resistance on anolyte composition has been studied using microbial fuel cell (MFC) model. Strain Gluconobacter oxydans subsp. industrius VKM B-1280 was a biocatalyst; glucose was used as a fuel. The following anolyte compositions were considered: (1) water-soluble mediator 2,6-dichlorophenol indophenol (DCPIP) in combination with suspension and immobilized bacteria and (2) hydrophobic mediators ferrocene and 1,1'-dimethylferrocene in combination with immobilized bacteria. It was shown that DCPIP in combination with immobilized bacteria versus the cell suspension increases the generated EMF for 36%, current for 25%, power for 56%, and inner resistance for 14%. Ferrocene seems to be more preferable as compared with 1,1'-dimethylferrocene. Ferrocene gives higher values of the generated EMF (for 8%) and current (for 47%), as well as decreases the inner resistance of MFC for 38%. The proposed system can be used for rapid qualitative and quantitative assessment of the "fuel-cell-mediator-electrode" interaction under charge transfer and is used in the search of effective anolyte compositions.

No abstract

⎯The relevant sol-gel encapsulation methods to design ORMOSIL (organically modified silica) protective shells around Debaryomyces hansenii yeast cells have been studied. Encapsulation is based on spontaneous "cell-in-shell" 3D structures. The physiological activity of the sol-gel encapsulated cells was determined by measurement of the oxidative activity of a BOD biosensor containing ORMOSIL-encapsulated cells. It was shown that the shells around the microbial cells did not prevent substrate diffusion and had excellent protection from extreme environmental factors (heavy metal ions, high pH, and UV radiation). In addition, it was found that the BOD biosensor surpasses some other known biosensors in their basic characteristics, including sensitivity, stability, and reproducibility. These results are important for the development of innovative methods of cell encapsulation and the creation of biocatalysts used in biotechnology and ecology.