Microbiological oxidation of long-chain aliphatic compounds. IV. Alkane derivatives having polar terminal groups

Medelamine C, A New ω-Hydroxy Alkylamine Derivative from Endophytic Streptomyces sp. YIM 66142

A new alkylamine derivative and a common fatty acid were isolated from Streptomyces sp. YIM 66142. On the basis of spectral data, including HRMS, NMR and 2D NMR, their structures were determined as medelamine C (1) and isomyristic acid (2). The ω-hydroxyl group in structure 1 is rare in a natural alkylamine. The possible biosynthetic pathway in the genus Streptomyces from isomyristic acid (2) to medelamines is proposed. Compound 1 showed no obvious cytotoxicity against HL-60, SMMC-7721, A-549, MCF-7, SW480 cell lines. The ω-hydroxyl and the acetyl at NH in compound 1 decreased its cytotoxicity in comparison with that of medelamine.

Volatile organic compounds (VOCs) in air from Nisyros Island (Dodecanese Archipelago, Greece): Natural versus anthropogenic sources

This study presents the chemical composition of VOCs in air and gas discharges collected at Nisyros Island (Dodecanese Archipelago, Greece). The main goals are i) to discriminate between natural and anthropogenic VOC sources and ii) to evaluate their impact on local air quality. Up to 63 different VOCs were recognized and quantitatively determined in 6 fumaroles and 19 air samples collected in the Lakki caldera, where fumarolic emissions are located, and the outer ring of the island, including the Mandraki village and the main harbor. Air samples from the crater area show significant concentrations of alkanes, alkenes, cyclic, aromatics, and S- and O-bearing heterocycles directly deriving from the hydrothermal system, as well as secondary O-bearing compounds from oxidation of primary VOCs. At Mandraki village, C6H6/Σ(methylated aromatics) and Σ(linear)/Σ(branched) alkanes ratios <1 allow to distinguish an anthropogenic source related to emissions from outlet pipes of touristic and private boats and buses.

Degradation of C2-C15 volatile organic compounds in a landfill cover soil

The composition of non-methane volatile organic compounds (hereafter VOCs) in i) the cover soil, at depths of 30, 50 and 70 cm, and ii) gas recovery wells from Case Passerini landfill site, (Florence, Italy) was determined by GC-MS. The study, based on the analysis of interstitial gases sampled along vertical profiles within the cover soil, was aimed to investigate the VOC behaviour as biogas transits from a reducing to a relatively more oxidizing environment. A total of 48 and 63 different VOCs were identified in the soil and well gases, respectively. Aromatics represent the dominant group (71.5% of total VOC) in soil gases, followed by alkanes (6.8%), ketones (5.7%), organic acids (5.2%), aldehydes (3.0%), esters (2.6%), halogenated compounds (2.1%) and terpenes (1.3%). Cyclics, heterocyclics, S-bearing compounds and phenols are <or=1%. In the wells the VOC composition is characterized by higher concentrations of cyclic (7.6%) and S-bearing compounds (2%) and lower concentrations of O-bearing compounds. The vertical distribution of VOCs in the cover soil shows significant variations: alkanes, aromatics and cyclics decrease at decreasing depth, whereas an inverse trend is displayed by the O-bearing species. Total VOC and CH(4) concentrations at a depth of 30 cm in the soil are comparable, inferring that microbial activity is likely affecting VOCs at a very minor extent with respect to CH(4). According to these considerations, to assess the biogas emission impact, usually carried out on the sole basis of CO(2) and CH(4) emission rates, the physical-chemical behaviour of VOCs in the cover soil, regulating the discharge of these highly contaminant compounds in ambient air, has to be taken into account. The soil vertical distribution of these species can be used to better evaluate the efficiency of oxidative capability of intermediate and final covers.

Cytochromes P450 of the sophorose lipid-producing yeast Candida apicola: heterogeneity and polymerase chain reaction-mediated cloning of two genes

Candida apicola belongs to a group of yeasts producing high amounts of surface-active extracellular glycolipids consisting of sophorose and long-chain-omega- and (omega-1)-hydroxy fatty acids. The involvement of cytochrome P450 in the synthesis of sophorose lipid by the hydroxylation of long-chain fatty acids was suggested from a simultaneous increase of cellular P450 content. Hydroxylation studies indicated the existence of multiple P450 forms capable of hydroxylating not only long-chain fatty acids, but also n-alkanes. In this report, two different P450 DNA fragments amplified in a polymerase chain reaction with heterologous primers and chromosomal DNA of Candida apicola were used as homologous probes for the isolation of full-length clones from a genomic library. The open reading frames of both genes encode proteins of 519 amino acids with calculated molecular weights of 58,656 and 58,631, respectively, that contain N-terminal membrane anchor sequences and hallmark residues, in common with other eukaryotic P450s. The deduced amino acid sequences of the C. apicola P450 genes are 84.4% identical. They share 34.5 to 44.1% identity with the proteins of the yeast family CYP52 and about 25% identity with fatty acid hydroxylases of higher eukaryotes (family CYP4A) and of Bacillus megaterium (CYP102). Southern hybridization experiments revealed the existence of further P450-related genes in C. apicola. According to the P450 nomenclature system, the cloned genes were named CYP52E1 and CYP52E2, establishing a new subfamily in yeast family CYP52.