Microbial degradation of petroleum hydrocarbons.

Biodegradation of petroleum hydrocarbons by oleophilic strain of Pseudomonas aeruginosa NCIM 5514

Synergistic ex-situ biodegradation of crude oil by halotolerant bacterial consortium of indigenous strains isolated from on shore sites of Gujarat, India

Environmental pollution with petroleum toxic products has afflicted various ecosystems, causing devastating damage to natural habitats with serious economic implications. Some crude oil components may serve as growth substrates for microorganisms. A number of bacterial strains reveal metabolic capacities to biotransform various organic compounds. Some of the hydrocarbon degraders are highly biochemically specialized, while the others display a versatile metabolism and can utilize both saturated aliphatic and aromatic hydrocarbons. The extended catabolic profiles of the latter group have been subjected to systematic and complex studies relatively rarely thus far. Growing evidence shows that numerous bacteria produce broad biochemical activities towards different hydrocarbon types and such an enhanced metabolic potential can be found in many more species than the already well-known oil-degraders. These strains may play an important role in the removal of heterogeneous contamination. They are thus considered to be a promising solution in bioremediation applications. The main purpose of this article is to provide an overview of the current knowledge on aerobic bacteria involved in the mineralization or transformation of both n-alkanes and aromatic hydrocarbons. Variant scientific approaches enabling to evaluate these features on biochemical as well as genetic levels are presented. The distribution of multidegradative capabilities between bacterial taxa is systematically shown and the possibility of simultaneous transformation of complex hydrocarbon mixtures is discussed. Bioinformatic analysis of the currently available genetic data is employed to enable generation of phylogenetic relationships between environmental strain isolates belonging to the phyla Actinobacteria, Proteobacteria, and Firmicutes. The study proves that the co-occurrence of genes responsible for concomitant metabolic bioconversion reactions of structurally-diverse hydrocarbons is not unique among various systematic groups.

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Aerobic bacteria degrading both n -alkanes and aromatic hydrocarbons: an undervalued strategy for metabolic diversity and flexibility

With increasing demands of fossil fuel energy, extensive exploration of natural sources has caused a number of large scale accidental spills of crude oil and resulted in some significantly environmental disasters. The consequence of oil pollution to environment and human health has brought a serious challenge to environmental scientists. Physical and chemical approaches to cleanup oil spills are too expensive and create adverse effects. Bioremediation has shown a great potential and competitive privilege because of environment friendly and cost effective. A number of efficient microbial strains have been identified and isolated, which can effectively degrade various components of petroleum oil. However, the biodegradation efficiency is usually limited by abiotic factors, such as temperature and pH, which are hardly to be controlled in the in situ condition but adequate oxygen supply and nutrient balancing are of importance to impact microbial functions. Therefore, this review especially addresses potential approaches to improving bioremediation of crude oil by supplying solid oxygen and adjusting C: N: P ratio to optimize microbial activities in order to improve the effectiveness and efficacy of bioremediation of crude oil pollutants. In addition, it also elucidates advantages of bioremediation, isolation of selective microbial strains, and evaluation of the biodegradation rates.

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Potential Approaches to Improving Biodegradation of Hydrocarbons for Bioremediation of Crude Oil Pollution

A feasibility study was conducted to evaluate the capability of bacterial strains to degrade crude oil under in vitro conditions. Pseudomonas strain PS-I could degrade alkanes (70.69%) and aromatics (45.37%). Alkanes and aromatic fractions separated by column chromatography were analyzed by gas chromatography. In case of Pseudomonas strain PS-I, nC 17 /Pr, nC 18 /Ph ratios decreased from 2.5100 to 0.1232 and from 7.2886 to 0.3853, respectively. It was concluded that out of the isolated strains, Pseudomonas strain PS-I, PS-II and PS-III were comparatively better and potent hydrocarbon degraders. Pseudomonas strain PS-I was almost comparable with standard strain of Acinetobacter calcoaceticus in crude oil biodegradation potency.

Isolation of hydrocarbon degrading bacteria from soils contaminated with crude oil spills.

Hydrocarbon degrading microorganisms play a major r ole in the environment. In the present study crude oil degrading fungal strain Aspergillus niger was isolated from o il contaminated soil near crude oil production well (Lingala) Andhra Pradesh. The rate of reduction in some petroleum hy drocarbon fractions, such as n-alkanes, aromatics, nitrogen, sulfur and oxygen (NSO)-containing compounds and polycycli c aromatic hydrocarbons (PAHs), were monitored by m eans of gas chromatography. The nC 17/Pristine and n C18/Phytane ratios, extrapolated from the GC profiles decreased from the initial value of 2.510 and 7.289 to 0.132 and 0.474 respect ively at day 60.

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Studies on biodegradation of crude oil by Aspergillus niger

A feasibility study was conducted prior to onsite full-scale bioremediation study. This feasibility study has investigated the possibility of bioaugmentation of polycyclic aromatic hydrocarbon (PAH)-polluted soil with PAH-degrading strains or consortia. Five treatment optionsOil alone, Oil + Indigenous microflora, Oil + nutrients, Oil + nutrient + tilling, Oil + nutrient + tilling + developed consortium were evaluated. Out of five treatments the application of bacterial consortium, nutrients and environmental factors resulted in 79.16% removal of TPH in 60days, compared to 30.24% removal of TPH carried out by indigenous microflora. The results of High-pressure liquid chromatographic analysis showed that the ratio of di / tri aromatics decreased from initial 0.63 to 0.25 with progressive treatment of nutrient addition, nutrient+tilling, nutrient+tilling+microbial seeding. Similar effect was observed in di / di+tri aromatics ratios which also decreased 0.31 to 0.20 by bioaugmentation only.

https://print.ispub.com/api/0/ispub-article/12388

Padma Singh

Papers

Isolation of hydrocarbon degrading bacteria from soils contaminated with crude oil spills.

Studies on biodegradation of crude oil by Aspergillus niger

Polycyclic aromatic hydrocarbon degradation by developed consortium in microcosms study.