Recent advances in molecular biology have extended our understanding of the metabolic processes related to microbial transformation of petroleum hydrocarbons. The physiological responses of microorganisms to the presence of hydrocarbons, including cell surface alterations and adaptive mechanisms for uptake and efflux of these substrates, have been characterized. New molecular techniques have enhanced our ability to investigate the dynamics of microbial communities in petroleum-impacted ecosystems. By establishing conditions which maximize rates and extents of microbial growth, hydrocarbon access, and transformation, highly accelerated and bioreactor-based petroleum waste degradation processes have been implemented. Biofilters capable of removing and biodegrading volatile petroleum contaminants in air streams with short substrate-microbe contact times ( 2 S and sulfoxides from petrochemical waste streams. Microbes also have potential for use in removal of nitrogen from crude oil leading to reduced nitric oxide emissions provided that technical problems similar to those experienced in biodesulfurization can be solved. Enzymes are being exploited to produce added-value products from petroleum substrates, and bacterial biosensors are being used to analyze petroleum-contaminated environments.

Recent Advances in Petroleum Microbiology

Interest in the biodegradation mechanisms and environmental fate of polycyclic aromatic hydrocarbons (PAHs) is prompted by their ubiquitous distribution and their potentially deleterious effects on human health. PAHs constitute a large and diverse class of organic compounds and are generally

Biodegradation of high-molecular-weight polycyclic aromatic hydrocarbons by bacteria.

Bioremediation of soil contaminated with polynuclear aromatic hydrocarbons (PAHs): A review

Polynuclear aromatic hydrocarbons in the United Kingdom environment: a preliminary source inventory and budget.

Biosurfactants production and possible uses in microbial enhanced oil recovery and oil pollution remediation: a review

Contributors. Preface M.M. Haggblom, I.D. Bossert. Part I: Introduction. 1. Halogenated Organic Compounds - A Global Perspective M.M. Haggblom, I.D. Bossert. Part II: Microbial Processes. 2. Microbial Ecology of Dehalogenation I.D. Bossert, M.M. Haggblom, L.Y. Young. 3. Diversity of Dechlorinating Bacteria F.E. Loffler, J.R. Cole, K.M. Ritalahti, J.M. Tiedje. 4. Thermodynamic Considerations for Dehalogenation J. Dolfing. 5. Dehalogenation by Anaerobic Bacteria C. Holliger, C. Regeard, G. Diekert. 6. Biodegradation of Chlorinated Compounds by White-Rot Fungi J.A. Field. Part III: Biochemistry and Chemistry. 7. Bacterial Growth on Halogenated Aliphatic Hydrocarbons: Genetics and Biochemistry D.B. Janssen, J.E. Oppentocht, G.J. Poelarends. 8. Aromatic Dehalogenases: Insights into Structures, Mechanisms, and Evolutionary Origins S.D. Copley. 9. Abiotic Dehalogenation by Metals L.A. Totten, N.M. Assaf-Anid. Part IV: Environmental Fate and Applications. 10. Bioavailability of Organohalides Kyoungphile Nam, J.J. Kukor. 11. Biotransformation of Halogenated Pesticides D.D. Focht. 12. Biodegradation of Atmospheric Halocarbons R.S. Oremland. 13. Dechlorination of Sediment Dioxins: Catalysts, Mechanisms, and Implications for Remedial Strategies and Dioxin Cycling C.L. Gruden, Q. Shiang Fu, A.L. Barkovskii, I.D. Albrecht, M.M. Lynam, P. Adriaens. 14. Redox Conditions and the Reductive/Oxidative Biodegradation of Chlorinated Ethenes in Groundwater Systems F.H. Chapelle, P.M. Bradley.15. Microcosms for Site-Specific Evaluation of Enhanced Biological Reductive Dehalogenation D.E. Fennell, J.M. Gossett. 16. Chlorinated Organic Contaminants from Mechanical Wood Processing and Their Bioremediation M.M. Laine, M.K. Mannisto, M.S. Salkinoja-Salonen, J.A. Puhakka. 17. Polychlorinated Biphenyls in Aquatic Sediments: Environmental Fate and Outlook for Biological Treatment D.L. Bedard. Part V: Summary. 18. Environmental Dehalogenation - Problems and Recommendations C.E. Castro. Index.

Dehalogenation : microbial processes and environmental applications

In a previous study on oily sludge disposal by land treatment, PAH as a class were found to be biodegraded more rapidly than the total solvent-extractable hydrocarbons of the sludge. This somewhat surprising result was apparently due to a predominance of low molecular weight PAH (less than or equal to 3 rings) in the sludge sample. The higher molecular weight PAH (greater than or equal to 4 rings) exhibited persistence that seemed to increase with the number of rings and the degree of ring condensation. In order to verify and extend these observations, the authors have undertaken here a systematic study on the structure-biodegradability relationship (SBR) of PAH in soil. Since it was expected that the majority of the PAH would be degraded cometabolically rather than in the substrate utilization mode, 1-phenyldecane was added as primary substrate in combination with all the PAH tested. In preliminary tests, 1-phenyldecane proved to be more effective in stimulating the biodegradation of 1,2-benzpyrene (benzo(a)pyrene) than either n-hexadecane, naphthoic acid or sewage sludge. The presence of an additional hydrocarbon substrate made this SBR study also more relevant to our previous work on the fate of PAH during the disposal of oily sludges by land treatment.

Structure-biodegradability relationships of polycyclic aromatic hydrocarbons in soil

A 1,280-day laboratory simulation of the "landfarming" process explored the fate in soil of polynuclear aromatics (PNAs) and total extractable hydrocarbon residues originating from the disposal of an oily sludge. In addition to the measurement of CO(2) evolution, periodic analyses of PNAs and hydrocarbons monitored biodegradation activity. The estimation of carbon balance and of soil organic matter assessed the fate of residual hydrocarbons. Seven sludge applications during a 920-day active disposal period were followed by a 360-day inactive "closure" period with no further sludge applications. A burst of CO(2) evolution followed each sludge addition, but substantial amounts of undegraded hydrocarbons remained at the end of the study. Hydrocarbon accumulation did not inhibit biodegradation performance. Conversion of hydrocarbons to CO(2) predominated during active disposal; incorporation into soil organic matter predominated during the closure period. In this sludge, the predominant PNAs were degraded more completely (85%) than total hydrocarbons. Both biodegradation and abiotic losses of three- and four-ring PNAs contributed to this result. Some PNAs with five and six rings were more persistent, but these constituted only a small portion of the PNAs in the sludge. The study confirmed that the microbially mediated processes of mineralization and humification remove sludge hydrocarbons from soils of landfarms with reasonable efficiency.

Ingeborg D. Bossert

Papers

Dehalogenation : microbial processes and environmental applications

Structure-biodegradability relationships of polycyclic aromatic hydrocarbons in soil

Fate of hydrocarbons during oily sludge disposal in soil.

Halogenated organic compounds - a global perspective

Plant growth in soils with a history of oily sludge disposal