Biodegradation of gasoline: kinetics, mass balance and fate of individual hydrocarbons

The degradation of gasoline by a microflora from an urban waste water activated sludge was investigated in detail. Degradation kinetics were studied in liquid cultures at 30 degrees C by determination of overall O2 consumption and CO2 production and by chromatographic analysis of all 83 identifiable compounds. In a first fast phase (2 d) of biodegradation, 74% of gasoline, involving mostly aromatic hydrocarbons, was consumed. A further 20%, involving other hydrocarbons, was consumed in a second slow phase (23 d). Undegraded compounds (6% of gasoline) were essentially some branched alkanes with a quaternary carbon or/and alkyl chains on consecutive carbons but cycloalkanes, alkenes and C10- and C11-alkylated benzenes were degraded. The degradation kinetics of individual hydrocarbons, determined in separate incubations, followed patterns similar to those observed in cultures on gasoline. Carbon balance experiments of gasoline degradation were performed. The carbon of degraded gasoline was mainly (61.7%) mineralized into CO2, the remaining carbon being essentially converted into biomass.     

Distribution and fate of aliphatic and aromatic hydrocarbons in Antarctic fauna and environment

With the depletion of oil resources in more accessible areas, those of remote regions are being considered or indeed are now being exploited. In many of these regions, especially the polar ones, little is known of the effects such exploitation will have on the environment. But it is known that the ecosystems are often subject to great stress by natural climatic conditions and additional burdens imposed by man may have catastrophic environmental effects. South Georgia, a sub-Antarctic island, has a history of industrial activity mainly concerned with whaling operations that peaked around 1925–1935 but has since declined to virtually nothing. Studies of the ecology of the area provided a unique opportunity to assess the long-term effects that such activities had on the ecosystem. Off the whaling stations a considerable amount of waste material, including fuel oil, was released into the bays and inevitably some of this material was deposited in the sediments. Chemical evidence in the form of both paraffinic and aromatic hydrocarbons still persists in the sediments. The implications of this persistence in relation to the possible influence of the low temperature conditions are discussed. The superficial sediments, marine biota and terrestrial plants, which since 1965 have returned virtually to a pristine state, contain hydrocarbons essentially similar to unpolluted areas around the coast of Britain. Relatively high levels of carcinogenic/mutagenic polynuclear aromatic hydrocarbons in surface sediments suggests a world-wide background of abiogenic hydrocarbons probably disseminated by airborne transport. This appears to indicate that contamination reaches even remote parts of the world in relatively undiminished quantities.     

Production, use and fate of Chilean brown seaweeds: re-sources for a sustainable fishery

Chile is an important producer of brown seaweeds representing 10% of world supply. Landings of Chilean kelp fluctuated between 40,000 t.year⁻¹ in the early ‘80s to 250,000 t.year⁻¹ more recently. Commercialized algae come from natural populations and no mass-cultures of involved species have been established. Four species of brown algae are commercially collected in the country: Lessonia trabeculata, L. nigrescens, Macrocystis pyrifera and M. integrifolia. Since 2000, the demand of alginate sources and food for cultivated abalones dramatically raised the harvesting of these species. Direct evaluations of Lessonia spp. and Macrocystis standing-stocks were made along 700 km of coast in northern Chile. Lessonia spp. estimated populations exceed 900,000 t, whereas M. integrifolia does not exceed 300 t. The insights provided indicate that sustainability of Chilean kelp subjected to intense harvesting would require management programs including the following bio-ecological recommendations: (1) to harvest the entire plant including the holdfast; (2) to harvest plants larger than 20 cm in diameter; (3) to harvest plants sparsely, selecting mayor specimens; (4) rotation of harvesting areas; and (5) for Macrocystis, to cut the canopy 1–2 m from the surface. They must be implemented in a National Program of Kelp Management, elaborated by government, scientists, fisherman, and industry.     

The fate of total petroleum hydrocarbons during oily sludge composting: a critical review

Reviews in Environmental Science and Bio/Technology - In this review, studies on petroleum sludge composting have been investigated in the aim to understand the sludge biotransformation and...     

Metal-mediated and metal-catalyzed hydrolysis of nitriles

The essential goals of this review are the following: (i) to verify various factors which affect the metal-mediated hydrolysis of organonitriles; (ii) to draw attention to unusual conversions of RCN species, yet underdeveloped and non-systematic, which involve hydrolysis and lead to compounds of synthetic and/or pharmacological significance. The metal-mediated and/or metal-catalyzed reactions of RCN species are surveyed and the experimental material on metal-mediated hydration of RCN species at diverse metal centers along the Periodic Table is summarized in a tabular form.     

Production of single cell protein from hydrocarbons byArthrobacter simplex 162

A strain ofArthrobacter simplex was selected as source of single cell protein for its good growth on hydrocarbons and its high protein content. The strain was able to grow on purely synthetic medium with hydrocarbons as sole carbon source. Hexadecane and ammonium sulphate were found as the most suitable C and N sources, respectively. Among the organic supplements yeast extract (0.01 %) showed the best effect. The optimum pH was 7.2–7.6 and the optimum temperature for growth was 32 °C. Penicillin, sodium dodecyl sulphate, EDTA and Tween 80 had either a very little stimulatory effect, no effect or an inhibitory effect.     

The microbiological fate of polycyclic aromatic hydrocarbons: carbon and oxygen balances for bacterial degradation of model compounds

A series of pure bacterial strains belonging mainly to theRhodococcus andPseudomonas genera were grown on one of the following polycyclic aromatic hydrocarbons (PAH) supplied as sole carbon and energy source: naphthalene, fluorene, phenanthrene, anthracene, fluoranthene and pyrene. In each case, a quantitative evaluation of the carbon repartition of the PAH degraded into CO₂, biomass and water-soluble metabolites was carried out. In addition, the kinetics of oxygen consumption and of water-soluble metabolite accumulation during PAH biodegradation was followed with respirometric equipment. Satisfactory carbon balances were obtained and the data correlated well with oxygen consumption values. The results show that growth on PAH presents high mineralization yields (from 56% to 77% of carbon) and sizeable production of biomass (from 16% to 35% of carbon) and limited but significant accumulation of metabolites (from 5% to 23% of carbon). The mineralization yields were higher and biomass yields lower in the case of higher PAH. Some differences between strains were also observed.     

Stabilization of luciferase intermediates by fatty amines, amides, and nitriles.

Long-chain aliphatic amides, mono- and diamines, mono- and dialcohols, and nitriles were found to inhibit the bacterial luciferase reaction by binding with an enzyme intermediate (II, the luciferase-bound 4 alpha-flavin hydroperoxide). Inhibition was determined by measuring the decay rates of the inhibitor-intermediate II complex at different inhibitor concentrations. The data fit a model which was used to estimate the KI. At high concentrations, a plot of the decay rate (k) vs 1/[I] produced a straight line; extrapolation of this to 1/[I] = 0 yields an estimate of the decay rate at infinite inhibitor concentration which we defined as the inhibitor-enzyme-substrate stabilization constant, kESI.     

Production and fate of faecal pellets during summer in an East Antarctic fjord

The abundance of small faecal pellets is high in marine waters. Little is known, however, about the processes governing their production and fate in the water column. We investigated faecal pellet production and flux in relation to the phytoplankton and copepod assemblages present in Ellis Fjord, Antarctica. Results show that the phytoplankton community shifted from a dominance of diatoms to that of a cryptomonad species during late January. This coincided with an increase in abundance of the small copepods Paralabidocera antarctica and Oithona similis, although Oncaea curvata was still the dominant species. The mean faecal pellet flux was 9943 pellets m^–2 d^–1. Only 37% of the faecal pellet flux at 5 m sedimented to 10 m depth, 15% to 20 m, and 12% to 40 m depth. Our results suggest that recycling of faecal pellets by copepods contributes to this decreased flux with increasing depth, which concurs with results from large scale oceanic studies. Additionally, we propose that the summer ice melt changes the physical characteristics of the water column and the phytoplankton species abundance and distribution; both of which potentially impact on the distribution and abundance of copepods, thereby regulating faecal pellet flux.     

Production of L-glutamic acid from hydrocarbons: Incorporation of molecular oxygen

The production of L -glutamic acid from hydrocarbons by a newly isolated bacterium, which was identified as Corynebacterium, was investigated. The outstanding characteristic of this bacterium was found to be an accessory requirement of thiamine for growth. The optimum concentration of thiamine for growth was 50 μg./liter, while that for L -glutamic acid production was 3–5 μg./liter. n-Paraffins ranging from dodecane to heptadecane were best for L -glutamic acid production, and about 5 g. of L -glutamic acid were obtained from 30 g. of these individual n-paraffins. On the other hand, a tracer experiment using oxygen-18 revealed that molecular oxygen was incorporated into L -glutamic acid produced from dodecane. Based on the incorporation value of molecular oxygen in L -glutamic acid, a hypothetical pathway for the biosynthesis of L -glutamic acid from dodecane was discussed.     

The synthesis and chromatography of peptine nitriles

Di- and tripeptide nitriles, glycylaminoacetonitrile (Gly-AAN), diglycylaminoacetonitrile (Gly-Gly-AAN), alany-alpha-aminopropionitrile (Ala-APN), and dialanyl-alpha-aminopropionitrile (Ala-Ala-APN) were synthesized first. These peptide nitriles and related peptides and peptide amides were analyzed by means of ion-exchange chromatography. The every two diastereomers of dialanine, dialanine amide, and Ala-APN were separated into two peaks by using a pH 3.25 buffer as an eluent. The four isomers of trialanine, trialanine amide, and Ala--Ala APN gave four, two, and one peak, respectively under the same conditions. The trimethylsilyl derivatives of alanyl peptides and related compounds were analyzed by means of gas chromatogrpahy combined with mass-spectrometry. The parent (M+ and/or M+-15) and other mass numbers observed in their mass-spectra supported the introduction of various numbers of trimethylsilyl groups.     

The synthesis and chromatography of peptide nitriles

Di- and tripeptide nitriles, glycylaminoacetonitrile (Gly-AAN), diglycylaminoacetonitrile (Gly-Gly-AAN), alanyl--aminopropionitrile (Ala-APN), and dialanyl--aminopropionitrile (Ala-Ala-APN) were synthesized first.These peptide nitriles and related peptides and peptide amides were analyzed by means of ion-exchange chromatography. The every two diastereomers of dialanine, dialanine amide, and Ala-APN were separated into two peaks by using a pH 3.25 buffer as an eluent. The four isomers of trialanine, trialanine amide, and Ala-Ala-APN gave four, two, and one peak, respectively under the same conditions.The trimethylsilyl derivatives of alanyl peptides and related compounds were analyzed by means of gas chromatography combined with mass-spectrometry. The parent (M⁺ and/or M⁺-15) and other mass numbers observed in their mass-spectra supported the introduction of various numbers of trimethylsilyl groups.     

On knowledge, policy, practice, and fate.

Knowledge of the nation's health and nutritional status is dated, uncertain, incomplete, and complex, whereas politicans demand simplicity and administrators, practicability, and everyone wants more and better information. Rational policy, the unicorn intellectuals hunt, should combine clarity, realism, and conviction, which calls for a touch of passion. Attempts to reconcile these contradictory elements can lead to dangerous political pressures on research; the simplification, exaggeration, and over-generalization of findings; and excessive expectations for humdrum programs that often bear little resemblance to their glorified goals. Inadequate knowledge can justify both action and inaction, which are merely different lays of meeting our fate. The ultimate goal of health and nutrition policy, it may be said, is a long and healthy life and a quick and happy death. That may be desirable, but is it attainable.