Microcosm experiments were conducted to quantify carbon isotope fractionation during aerobic biodegradation of n-alkanes (from C3 to C10) and monoaromatic hydrocarbons in unsaturated alluvial sand. In single compound experiments with n-alkanes, the largest enrichment factor was obtained for propane ( 10.8 ± 0.7‰). The magnitude of the enrichment factor decreased with increasing number of carbon...

Biotransformation using alkane-oxidizing bacteria or their alkane hydroxylase (AH) systems have been little studied at the molecular level. We have cloned and sequenced genes from Gordonia sp. TF6 encoding an AH system, alkB2 (alkane 1-monooxygenase), rubA3 (rubredoxin), rubA4 (rubredoxin), and rubB (rubredoxin reductase). When expressed in Escherichia coli, these genes allowed the construction...

The ability of two recently isolated actinobacteria, that degrade medium and long chain n-alkanes in laboratory water medium, was investigated in soil microcosms using different standard soils that were artificially contaminated with n-alkanes of different length (C(12)- C(20)- C(24)- C(30)). The two strains, identified as Nocardia sp. SoB and Gordonia sp. SoCp, revealed a similar high HC degra...

Three-layer feed-forward neural networks for the prediction of I3C NMR chemical shifts of alkanes through nine carbon atoms are used. Carbon atoms in alkanes are determined by 13 descriptors that correspond to the so-called embedding frequencies of rooted subtrees. These descriptors are equal to numbers of appearance of smaller structural skeletons composed of two through five carbon atoms. It ...

New molecular and thermal diffusion coefficients of binary mixtures of normal decane-normal alkanes and methylnaphthalene-normal alkanes are measured at atmospheric pressure and T = 25 degrees C. The normal alkanes used in this work include nC5-nC20. Thermal diffusion coefficients were measured in a thermogravitational column. Molecular diffusion coefficients were measured using an open-ended c...

Construction of highly efficient microbial cell factories producing drop-in biofuel alkanes is severely limited due to the lack of a fast detection method against alkanes. Here we first developed a sensitive fluorescent biosensor for rapid and in situ monitoring of intracellular alkane synthesis. Using GFP as reporter, the biosensor could actively respond to the intracellular alkane products, e...

Organic carbon (OC) and n-alkanes were investigated in the suspended matter (SM) and sur®cial sediments of the Arctic Ob and Yenisei Rivers and the adjacent Kara Sea. Organic nitrogen and dC values were determined as additional parameters in the sediments. OC and n-alkane concentrations were highly variable in space. This variability was interpreted as the result of a complex sedimentation patt...

We compare the growth dynamics of the three n-alkanes C(36)H(74), C(40)H(82), and C(44)H(90) on SiO(2) using real-time and in situ energy-dispersive x-ray reflectivity. All molecules investigated align in an upright-standing orientation on the substrate and exhibit a transition from layer-by-layer growth to island growth after about 4 monolayers under the conditions employed. Simultaneous fits ...

This paper represents a fragment of systematic studies on positron annihilation in solid saturated hydrocarbons (alkanes, paraffins) from C17H36 to C30H62. The Tao–Eldrup model and its extensions allow to identify the places in the crystalline structure where positronium is trapped, and estimate respective trap sizes. In the rigid phase I positronium locates mainly in two-dimensional empty spac...

In the present study, the microbial community and functional gene composition of a long-term active alkane-degrading methanogenic culture was established after two successive enrichment culture transfers and incubated for a total period of 1750 days. Molecular analysis was conducted after the second transfer (incubated for 750 days) for both the active alkanes-degrading methanogenic enrichment ...