Matthew J. Grossman

The Roles of Photooxidation and Biodegradation in Long-term Weathering of Crude and Heavy Fuel Oils

Abstract Although spilled oil is subject to a range of natural processes, only combustion, photooxidation and biodegradation destroy hydrocarbons and remove them from the biosphere. We present laboratory data that demonstrate the molecular preferences of these processes, and then examine some oil residues collected from previously documented releases to confirm the important roles that these processes play in removing spilled oil from both marine and terrestrial environments.

Deep Desulfurization of Extensively Hydrodesulfurized Middle Distillate Oil by Rhodococcus sp. Strain ECRD-1

ABSTRACT Dibenzothiophene (DBT), and in particular substituted DBTs, are resistant to hydrodesulfurization (HDS) and can persist in fuels even after aggressive HDS treatment. Treatment by Rhodococcussp. strain ECRD-1 of a middle distillate oil whose sulfur content was virtually all substituted DBTs produced extensive desulfurization and a sulfur level of 56 ppm.

Bioremediation of Stranded Oil on an Arctic Shoreline

Abstract The application of slow-release and soluble fertilizers proved to be an effective and environmentally benign way of stimulating oil biodegradation on an Arctic shoreline. Fertilizer application to the surface of the beach delivered nutrients to the oiled sediment beneath the beach surface. There was no significant run-off of this fertilizer to either the nearshore water or to unfertilized plots, and there were no adverse toxicological effects of the fertilizer application. The fertilizer application was followed by an increase in oxygen consumption and carbon dioxide evolution from the beach, increased microbial biomass, and significantly greater biodegradation of oil on the plots that had received fertilizer. The rate of oil biodegradation was approximately doubled over the course of a year by fertilizer applications in the first two months after the spill. Simple test kits proved adequate to monitor the fertilizer-application process in the field in a time frame that would allow the application process to be fine-tuned during treatment on a real spill. Simple test kits and portable instrumentation were useful in demonstrating the initial success of the bioremediation strategy.

Bioremediation technology development and application to the alaskan spill

ABSTRACT Bioremediation was used to clean oil-contaminated shorelines in Prince William Sound following the Exxon Valdez oil spill. Among the approaches considered for enhancing natural rates of oil biodegradation, nutrient applications became the principal focus. Bioremediation studies were conducted in a cooperative effort of Exxon, the U.S. Environmental Protection Agency, and scientists in academia. Field testing of nutriation of indigenous oil-eating microorganisms was conducted early in the summer of 1989, and full-scale application followed. Monitoring during the fall and winter of 1989–90 revealed the evident benefit of the technique and supported additional applications in 1990. The efficacy of bioremediation was demonstrated by measurement of numbers of hydrocarbon-degrading microorganisms, microbial hydrocarbon-degrading activities, and chemical changes in residual oil. This paper discusses laboratory and field programs demonstrating the efficacy and environmental safety of bioremediation, and ...

Substrate Preferences in Biodesulfurization of Diesel Range Fuels by Rhodococcus sp. Strain ECRD-1

ABSTRACT The range of sulfur compounds in fuel oil and the substrate range and preference of the biocatalytic system determine the maximum extent to which sulfur can be removed by biodesulfurization. We show that the biodesulfurization apparatus in Rhodococcus sp. strain ECRD-1 is able to attack all isomers of dibenzothiophene including those with at least four pendant carbons, with a slight preference for those substituted in the α-position. With somewhat less avidity, this apparatus is also able to attack substituted benzothiophenes with between two and seven pendant carbons. Some compounds containing sulfidic sulfur are also susceptible to desulfurization, although we have not yet been able to determine their molecular identities.

Comparison of the Emulsion Characteristics of Rhodococcus erythropolis and Ecsherichia coli SOXC‐5 Cells Expressing Biodesulfurization Genes

Biodesulfurization of fuel oils is a two‐phase (oil/water) process which may offer an interesting alternative to conventional hydrodesulfurization due to the mild operating conditions and reaction specificity afforded by the biocatalyst. For biodesulfurization to realize commercial success, a variety of process considerations must be addressed including reaction rate, emulsion formation and breakage, biocatalyst recovery, and both gas and liquid mass transport. This study evaluates emulsion formation and breakage using two biocatalysts with differing hydrophobic characteristics. A Gram‐positive ( Rhodococcus erythropolis) biocatalyst, expressing the complete 4S desulfurization pathway, and a Gram‐negative biocatalyst ( Escherichia coli), expressing only the gene for conversion of dibenzothiophene (DBT) to DBT sulfone, are compared relative to their ability to convert DBT and the ease of phase separation as well as biocatalyst recovery following desulfurization.

THE EFFECT OF BIOREMEDIATION ON THE MICROBIAL POPULATIONS OF OILED BEACHES IN PRINCE WILLIAM SOUND, ALASKA

ABSTRACT Bioremediation, the stimulation of the natural process of biodegradation, played an important role in the cleanup of the oil spill from the Exxon Valdez in Prince William Sound, Alaska. Since there were already substantial indigenous populations of oil-degrading microbes in the area, it was apparent that degradation was likely to be nutrient—not microbial—limited. Bioremediation therefore involved the application of carefully selected fertilizers to provide assimilable nitrogen and phosphorus to the indigenous organisms, with the intent to stimulate their activity and enhance their numbers. We show here that the indigenous microbial populations were indeed substantially increased, throughout the sound, approximately one month after widespread fertilizer applications in both 1989 and 1990. Furthermore, while oil-degrading bacteria made up a significant fraction of the microbial populations on contaminated beaches in September and October 1989, they had declined to less than 1 percent by the summer...

Bacterioferritin: A Hemoprotein Member of the Ferritin Family

Ferritin has been known in eukaryotic cells for over 50 years1 but only in the last 15 years has a ferritin-like molecule been recognized in bacterial systems. In 1979 2 the hemoprotein originally designated3 as Azotobacter vinelandii cytochrome b557.5 was shown to be ferritin-like in character on the basis of subunit size and composition, electron microscopy of the holoprotein, and physical characterization of the core iron. 2 Since this initial identification of bacterioferritin its presence has been established in a wide variety of prokaryotic organisms including Escherichia coli, 4 Pseudomonas aeruginosa 5 Nitrobacter winogradskii 5 Mycobacterium paratuberculosis, 7 Synechocystis P.C.C. 6803, 8 Yersinia pestis 9 and Rhodobacter capsulatus. 10 In each of the above species heme in the form of extractable protoporphyrin IX is intimately associated with the protein.

Improving Enzyme Activity and Broadening Selectivity for Biological Desulfurization and Upgrading of Petroleum Feedstocks

The objective of this project was to develop improved biocatalysts for desulfurization and upgrading of petroleum feedstocks. The goal was to improve the activity and broaden the selectivity of desulfurization enzymes using directed evolution as a tool as well as to explore the impact of ring-opening on biological desulfurization