Hydrocarbons - organic nutrients

The ease with which microorganisms can utilize hydrocarbons depends on the type of hydrocarbons present (Wyatt, 1984 Bartha and Atlas, 1987 Hettige, 1993) and the microorganisms (Table 4). 

Kerosene fuel contains approximately 57% alkanes. Alkanes with 10 to 22 carbon unit chains are the most easily utilized hydrocarbons. These alkanes are oxidized via the enzyme monooxygenase to yield the corresponding alcohol. This oxidation can be terminal or subterminal. With an attack at the terminal carbon, the hydrocarbon is converted directly to the primary alcohol. Some microorganisms will degrade hydrocarbons at a subterminal carbon, converting the hydrocarbon first to a secondary alcohol that is then further oxidized to a ketone and ester (Wyatt, 1984 Bartha and Atlas, 1987). The ester is finally hydrolyzed to form an acid and the primary alcohol. 

The alcohol is oxidized via the enzyme alcohol dehydrogenase to yield the corresponding aldehyde. 

The aldehyde is oxidized via the enzyme aldehyde dehydrogenase to yield fatty acid, which can be further 

Starting with even number carbon chain alkanes the fatty acid is oxidized by beta-oxidation to acetate. 

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The elemental and vitamin compositions of some representative yeasts are Hsted in Table 1. The principal carbon and energy sources for yeasts are carbohydrates (usually sugars), alcohols, and organic acids, as weU as a few other specific hydrocarbons. Nitrogen is usually suppHed as ammonia, urea, amino acids or oligopeptides. The main essential mineral elements are phosphoms (suppHed as phosphoric acid), and potassium, with smaller amounts of magnesium and trace amounts of copper, zinc, and iron. These requirements are characteristic of all yeasts. The vitamin requirements, however, differ among species. Eor laboratory and many industrial cultures, a commercial yeast extract contains all the required nutrients (see also Mineral nutrients). 

In another AT study, Terrado et al. [15] characterised pollution patterns in different parts of the Ebro catchment. In the upper part of the Ebro, pollution was found to be mainly in the form of heavy metals (Zn, Cu, Cr, Pb, Cd and Hg), polycyclic aromatic hydrocarbons (PAHs), hexachlorocyclohexanes (HCHs) and trichlorobenzenes (TCBs). Etrophic conditions were also found. Pollution was found to source mainly from industry and urbanisation. The central Ebro was characterised by nutrient pollution such as the accumulation of Ca, Na, Mg and K, which highlighted the importance of salinisation effects from intensive irrigation and soils with high salt content. In the lower Ebro, organic [DDTs, hexachlorobenzene (HCB) and hexachlorobutadiene (HCBu)] and heavy metal (Hg, Cd, Zn and As) contamination was found to derive mainly from industrial and agricultural activities. 

Total Organic Carbon Formations with a significant TOC content greater than the petroleum hydrocarbon content, as with peat-rich soil, can compete with the hydrocarbon-degrading microbes for oxygen and nutrients. A representative sample should thus be analyzed for TOC if organic matter is observed in soil samples or borings. 

The B S Research, Inc., B S Achieve-B S Industrial technology uses microorganisms (B S Industrial) with emulsifier and nutrients (B S Achieve) to treat contaminated soil and water. According to the technology developer, the technology degrades hydrocarbons, chlorinated solvents, polychlorinated biphenyls (PCBs), fertilizers, pesticides, and other hazardous organic compounds. 

Microcat (meaning microbial catalysts) products constitute a bioremediation technology used on wastewaters, sludges, and soils. Microcat products include specialized microbial cultures, nutrients, and surfactants to remediate organic contaminants such as petroleum hydrocarbons. The products used in site remediation include ... 

Majority MAE applications have been in the extraction of PAHs, PCBs, pesticides, phenols, and total petroleum hydrocarbons (TPHs) from environmental samples. MAE has also been used in the extraction of contaminants and nutrients from foodstuffs, active gradients from pharmaceutical products, and organic additives from polymer/plastics. Table 3.14 lists some typical applications. Readers interested in the details of MAE applications can find more information in some recent reviews [85-87],... 

Mixed with the waters of the Dnieper and Southern Bug rivers, a large amount of human-made nutrients, including nitrogen and phosphorus compounds, contaminants including heavy metals and hydrocarbons, as well as organic matter flows into the northwestern part of the Black Sea. The impact on the sea has become a very serious ecological problem. 

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