In this study twelve types of top soil were collected under aseptic conditions. The cellulose-decomposing rates of these were compared in order to determine the relative rates in the cellulose-decomposing potential of the microorganisms involved. Furthermore, this investigation is designed to acquire pertinent information on the rate at which natural cellulose materials are returned to available plant food.

No / Background Hair is degraded by the action of both dermatophytic and nondermatophytic microorganisms. The importance of understanding hair sample condition in archaeological and forensic investigation highlights the need for a detailed knowledge of the sequence of degradation in samples that have been either buried or left exposed at the ground surface. Objectives To investigate the sequence of biodegradative change to human terminal scalp hair from archaeological and forensic contexts. Methods Cut modern scalp hair from three individuals with caucasoid-type hair was inoculated with soil microorganisms through soil burial in the field and under laboratory conditions to produce experimentally degraded samples. The degraded hair fibres were subjected to detailed histological examination using a combination of high-resolution light microscopy, transmission electron microscopy and scanning electron microscopy to investigate the nature and sequence of degradative change to hair structural components. Results/discussion Degradation was found to occur first within the least structurally robust components that afford the least resistance to microbial/chemical attack. The sequence of degradation (most to least-reflecting degree of vulnerability) in the hair cuticle was as follows: (1) intercellular 6-layer (cell membrane complex); (2) endocuticle; (3) cell membrane ß-layers; (4) exocuticle; (5) epicuticle; and (6) A-layer. In the hair cortex this was as follows: (I) intercellular 6-layer (cell membrane complex); (II) cell membrane ß-layers; (III) intermacrofibrillar matrix/nuclear remnants; (IV) microfibrils; (V) intermicrofibrillar matrix; and (VI) pigment granules (the hair fibre component that was the least vulnerable to degradation). Conclusions The selective progress of degradation in the hair shaft has been charted and this provides a basis for further histological work in better understanding the condition of hair fibres derived from archaeological or forensic contexts as well as being relevant to investigation of diseased hair, in particular hair infected by dermatophytes and hair weakened by genetic hair shaft abnormalities.

No / Despite an increasing literature on the decomposition of human remains, whether buried or exposed, it is important to recognise the role of specific microenvironments which can either trigger or delay the rate of decomposition. Recent casework in Northern England involving buried and partially buried human remains has demonstrated a need for a more detailed understanding of the effect of contrasting site conditions on cadaver decomposition and on the microenvironment created within the grave itself. Pigs (Sus scrofa) were used as body analogues in three inter-related taphonomy experiments to examine differential decomposition of buried human remains. They were buried at three contrasting field sites (pasture, moorland, and deciduous woodland) within a 15km radius of the University of Bradford, West Yorkshire, UK. Changes to the buried body and the effect of these changes on hair and associated death-scene textile materials were monitored as was the microenvironment of the grave. At recovery, 6, 12 and 24 months post-burial, the extent of soft tissue decomposition was recorded and samples of fat and soil were collected for gas chromatography mass spectrometry (GCMS) analysis. The results of these studies demonstrated that (1) soil conditions at these three burial sites has a marked effect on the condition of the buried body but even within a single site variation can occur; (2) the process of soft tissue decomposition modifies the localised burial microenvironment in terms of microbiological load, pH, moisture and changes in redox status. These observations have widespread application for the investigation of clandestine burial and time since deposition, and in understanding changes within the burial microenvironment that may impact on biomaterials such as hair and other associated death scene materials.

Aerobic decomposition of hydrocarbon contaminants in anaerobic groundwater would be enhanced by oxygenating the water. This was done by injecting oxygen microbubbles in the soil matrix packed in a 7 ft by 7 ft by 5 inches in width Vertical Slice Test Cell, VSTC, and in a 30-inch column, also packed with sand. Transfer of oxygen to water was monitored after injecting oxygen microbubbles. Compared to sparged air and hydrogen peroxide injections documented in the literature to have transferred less than 2 percent oxygen to water, oxygen microbubbles transferred over 40 percent oxygen to the flowing groundwater. Also, after injection of microbubbles gas retentions over 70 percent were achieved. Oxygen Transfer Coefficients, KLa(s), were higher in layered soil in VSTC compared to non-layered soil when the same amounts of microbubbles were injected in the cell. The effect of cell layering, quality, stability, and the amount of microbubbles injections on transfer efficiency and gas holdup was studied. It was concluded that high initial gas holdups, KLa values oxygen transfer per time and percent oxygen transferred were important parameters in maintaining a sustained oxygen transfer zone. These experiments demonstrated that only one of these parameters can be at a maximum, say, a high percent oxygen transfer or a high percent initial retention or a high KLa value. However, a maximum value for one parameter is usually at the expense of the other two being low. The optimum values for these parameters would be dictated by the biochemical, sediment, and chemical oxygen demands placed on the oxygen transfer system. / Master of Science

The focus of this research was to acquire a better understanding of the sorption and desorption of pentachlorophenol to soil organic matter. In order to separate the reactions controlling the interactions with the soil organic matter from those associated with mineral surfaces, these experiments used only humic acids extracted from soil samples. The major focus of this study was to examine the effects of solution pH, humic acid concentration and contact time on the degree of sorption. The association reactions proceeded slowly. Even after 28 days, many solutions had not attained equilibrium. An increase in the solution pH led to a reduction in the amount of partitioning onto the humic material. At solution concentrations between 100 mg/L and 800 mg/L of total organic carbon (TOC), an increase in the humic acid concentration resulted in a lower partition coefficient. However, above a concentration of 800 mg/L TOC, further increases in the amount of humic material caused enhanced sorption. The particulate humic acids demonstrated a higher affinity for the pentachlorophenol than did the dissolved polymers. In the concentrated solutions, the majority of the humic acids were present in the particulate form. Two experiments focused on the effect of sorption on the bioavailability and solvent extraction of pentachlorophenol. The bioavailability data Suggested that the sorbed contaminant was not readily accessible to the microorganisms. The humic acids prevented the extraction of the sorbate by methyl-tert-butyl ether and methylene chloride. Recovery of the pentachlorophenol sorbed to the dissolved humic acids ranged from zero to 42.9 percent, depending on the solution pH. The removal of pentachlorophenol from the particulate matter varied from 25 percent to 90 percent. Longer contact times diminished the transfer of PCP associated with the solid humic acids to the solvent phase. The experimental results were not consistent with a simple, one mechanism model. The best explanation of the data was provided by a model which included liquid-liquid partitioning, surface sorption, absorption, and chemisorption. The dominant process depended on the contact time, solution pH, and concentration and nature of the humic acids. / Master of Science

Waste oil generated from industrial operations at a diesel locomotive maintenance facility was investigated to establish its treatability and potential volume reduction. The waste oil and water mixture separated into four distinct layers; free oil, emulsified oil, weathered oil, and wastewater. The research was conducted in a series of three batch experiments and focused on the emulsified and weathered oils. The waste oil was aerobically treated in nutrient amended, 55 gallon (208 L) drums for 38 to 42 days in 10 and 20 % mixtures with sufficient air for mixing and oxygen. Biodegradation, and the role of a synthetic surfactant in promoting biodegradation, was measured using chemical oxygen demand (COD), fluorescein diacetate (FDA), and gas chromatography (GC) analyses with extractable material. Dewatering of biodegraded oil was measured using capillary suction test (CST), time to filter (TTF), and percent cake solids. Batch 1 examined the role of bioaugmentation by comparing a 10% waste oil mixture that was augmented with a mixture of hydrocarbon degraders to a 10 % mixture of waste oil with no bioaugmentation. Final COD reductions were 59 (± 9) and 38 (±3) % for the bioaugmented and non-bioaugmented reactors, respectively. Chromatographs showed significant reduction in the abundance of peaks by the end of the experiment for both reactors. Overall results suggested that there was no significant difference in biodegradation capabilities between the amended and native microorganisms. Batch 2 was conducted to determine if a synthetic surfactant (Tween-80) could enhance biodegradation of a 10 % waste oil mixture. The surfactant-amended reactor showed COD reduction 3 days before the non-surfactant-amended reactor. Chromatographs showed similar results for both reactors with the non-surfactant-amended reactor showing slightly better degradation by the end of the experiment. The total COD reduction by the end of the experiment was the same in both (R1: 85 ± 20%, R2: 84 ± 16 %), suggesting that exogenous surfactant addition did not have a long-term impact in the biodegradation of the waste oil. Batch 3 examined the effect of different oil phases and concentrations on biodegradation and the dewatering characteristics of post-biodegraded waste oil. The 20 % weathered and emulsified waste oil mixture showed a clear delay in COD reduction (no notable reduction until day 24) compared to the 10 % weathered waste oil mixture. The final COD reductions were the same (R1: 48 ± 13%, R2: 49, ± 23 %). Chromatographs showed similar results for both reactors and indicated that degradation of the waste oil occurred in both reactors. The data suggest that the 20 % waste oil mixture can be degraded to the same extent as the 10 % mixture in 38 days. Dewatering characteristics, as measured by CST, were poor for the 20 % post-biodegraded combined waste oil mixture without conditioning. Conditioning with alum or ferric chloride substantially improved dewatering of the waste oil for the 20 % mixture but was of limited benefit for the 10 % mixture. Percent cake solids for conditioned 10 % post-biodegraded waste oil mixture was 44 (± 0.3) to 50 (± 1.7) % and 34 (± 0.3) to 50 (± 1.8) % for the 20 % mixture. The cake solids for the unconditioned 10 % mixture was 50 to 65 % and 54 to 68 % for the 20 % mixture. The higher percent cake solids for the unconditioned 20 % mixture was countered by the very high TTF (up to 30 min. to filter 50 mL) and the inability to dewater the sludge during the last five sampling events. Conditioning appeared to have a limited effect on the dewatering properties of the 10 % mixture. / Master of Science

There are more than three thousand landfills in the United States, in which approximately 55% (1998, U. S. EPA 1999) of the MSW generated in the US is buried. The majority of the landfills are conventional, but in the last two decades new types of landfills, called leachate recycle and bioreactor landfills, have been designed and tested as an enhanced environment for biochemical degradation of municipal solid waste. All the landfills are regulated under Subtitle D of the Resource Conservation and Recovery Act (RCRA). The shortage of time and money has limited the amount of research done on waste stability analysis. The purpose of this study was to evaluate the importance of lignocelluloses in biodegradation and the secondary settlement based on dry density and typical landfill evaluating parameters. Both parts of the study samples were collected and analyzed from eleven landfills. In the first part of the study, bioreactor landfills were found more effective, faster in the degradation of VS and cellulose as compared to conventional landfills. The time required for stabilization is reduced to about 1/3 that of conventional landfills. The lignocelluloses degradation that occurs in these landfills is happening in two phases. In the initial, rapid degradation phase, the primary degradation substrate is cellulose. In the second phase, after cellulose degraded to 15-20% of the waste, degradation of the remaining cellulose along with lignin and the hemicelluloses takes place. The start of lignin and hemicellulose degradation results in an increase in the biochemical methane potential (BMP). In the second part of the study, the addition of moisture to the landfills presented a contentious issue. Moisture is encouraged for MSW refuse degradation, but for settlement it reduces compressibility. In leachate recycle landfills, the dry density is higher than in conventional landfills; therefore there is more available room for further MSW load. The increase can reach up to 40 percent in total volume. / Master of Science

Synthetic plastics are intrinsic to modern human existence. Unfortunately, many challenges exist related to the accumulation of plastic waste, including greenhouse gas emissions, contamination of natural environments, and entrance into the food chain through microplastics. Therefore, new polymers are being developed that both compete with the capabilities and costs of petroleum-based plastics and have assured biodegradability. Through decades of research, plant oils have emerged as one of the leading options for alternative starting materials because of their feasibility for use in polymerization reactions, wide availability, renewability, and cost-effectiveness. In this work, cottonseed oil (CSO) and soybean oil (SBO) are successfully utilized to synthesize polymers with a range of promising properties. A nanocomposite was produced by incorporating cellulose nanocrystals (CNCs) into an epoxidized CSO (ECSO) polymer matrix. A significant improvement in properties such as tensile stiffness and strength, without any substantial decrease in extensibility or thermal integrity has been observed. This demonstrated that CNCs can be used to tune the CSO- based polymer properties. Enzymes are excellent alternatives to traditional catalysts as they eliminate the necessity of elevated reaction temperatures and pressures. Epoxidized SBO (ESBO) was polymerized using immobilized candida antarctica lipase B (Novozyme N435). The resulting polymer was inhomogeneous, with soluble waxy and insoluble solid components. Analyses of the soluble component indicated the formation of a multi-branched polymer, showing that a greener system may be used to produce ESBO-based polymers. It is necessary to test the biodegradability of biobased polymers to confirm their validity as alternatives to traditional plastics. Degradation of the CNC-incorporated CSO-based network polymer was characterized by submersing specimens into various aqueous media, including artificial seawater and saltwater, to simulate realistic end-of-use scenarios. Decomposition occurred due to hydrolysis of the many ester linkages within the polymer structure. The presence of CNCs appeared to enhance the rate of degradation. Overall, the hydrolytic susceptibility of the CSO-based network polymer was observed as enhanced by incorporating CNCs. In summary, this work demonstrates the viability of using plant oils and CNCs to produce biodegradable polymers with a range of properties, thus aiding in the effort to replace traditional plastics.

The use of alcohols as inexpensive octane enhancers in gasoline has contributed to an increased concern about the potential contamination of groundwater. Being highly soluble in water, alcohols may easily separate from other, more insoluble gasoline components, and rapidly enter the groundwater flow system. The alcohols are relatively tasteless and odorless, and thus, may go undetected until potentially harmful concentrations are reached. This study was designed to determine the potential for alcohol biodegradation in a groundwater system that had been previously contaminated with gasoline containing tertiary butyl alcohol (TBA). Laboratory microcosms, utilizing actual aquifer material and groundwater, were constructed to determine the rate of alcohol biodegradation in a system closely resembling the subsurface environment. The only microorganisms used were those naturally present in subsurface soil obtained aseptically. Bacterial counts and degradation kinetics were evaluated at each of three subsurface depths (10, 26, and 45 feet) and results were compared to similar studies utilizing uncontaminated aquifer material. Significant bacterial populations were found to exist at all depths studied in the contaminated subsurface system. Bacterial plate counts ranged from 10 6 to 10 7 colony forming units per gram of soil (dry weight). Methanol was found to be a readily degradable substrate. Complete degradation of up to 1000 mg/L was degraded in a matter of months. The biodegradation of methanol in the contaminated system was similar to that observed at pristine sites, indicating that a similar degradation mechanism is involved. TBA biodegradation in the contaminated system occurred and was accompanied by microbial growth. Complete TBA degradation of up to 100 mg/L occurred in less than one year. In contrast, TBA biodegradation in the uncontaminated systems occurred at a very slow rate, which appeared to be constant over time, and thus zero order. However, the zero order rate was found to vary directly with initial substrate concentration. Several mechanisms may explain TBA biodegradation, including the presence of a non-specific exocellular enzyme system. Such a system would describe observed results and suggest that a widespread potential exists for the degradation of a large number of organic compounds. / Ph. D.

This study was conducted to isolate and characterize bacteria that have the capacity to degrade both carbofuran and dicamba. The pathways of degradation for both pesticides were elucidated. An aerobic, carbofuran-degrading bacterium was isolated from a high concentration carbofuran bioreactor. The isolate degrades carbofuran at the upper limit of carbofuran solubility (approximately 700 mg L⁻¹), to carbofuran phenol. In aqueous mineral salts medium with carbofuran as Furadan 4F (6 g L⁻¹ a.i.), degradation of carbofuran to undetectable levels required approximately 100 days. Although carbofuran phenol was not completely degraded, the cells remained viable in the presence of unusually high concentrations of both surfactant and carbofuran phenol. Additional nutrient sources had little effect upon the rate of degradation of carbofuran in pure culture. A dicamba-degrading consortium enriched from wetland soil, using the batch culture method, was used to elucidate the pathway of dicamba degradation under anaerobic conditions. The consortium consisted of one sulfate reducing bacterium, one fermenter, and three methanogens. The sulfate reducing bacterium was isolated from the consortium using sulfate as a terminal electron acceptor and 2-bromoethanesulfonic acid was added to inhibit the growth of the methanogens. Since the fermenter is dependent upon the methanogens, elimination of these organisms caused the elimination of the fermenter. Three methanogens (Methanothrix, Methanosarcina and Methanospirillum sp) were isolated with acetate and headspace gas consisting of H₂-CO₂. Degradation of dicamba proceded through an initial demethylation reaction yielding 3,6-dichlorosalicylic acid, as determined by high performance liquid chromatography (HPLC) analysis of aqueous medium. This was followed by a reductive dehalogenation reaction at the meta position of 3,6-dichlorosalicylic acid forming 6-chlorosalicylic acid. The metabolites were isolated using thin layer chromatography. Confirmation of metabolite identity was achieved using HPLC, and mass spectrometry. It appears that the fermenter was responsible for mediating the demethylation reaction. The consortium was unable to mineralize the aromatic ring. The substrate specificity of the dicamba-degrading consortium was investigated. The consortium was found to have the capacity to mediate the reductive dehalogenation of both 3-chlorosalicylic acid and 2,5-dichlorobenzoic acid at the meta position. The consortium was unable to dehalogenate either 3-chlorobenzoic acid, 4-chlorosalicylic acid, 5-chlorosalicylic acid, or 2,5-dichlorophenol. Addition of the reducing agent cysteine (0.025% and 0.050%) to a yeast extract amended (0.04%) mineral salts medium containing 3-chlorosalicylic acid reduced the rate of dehalogenation compared to medium containing sodium sulfide as the reducing agent. Only limited dehalogenation of 3- chlorosalicylic acid and 2,5-dichlorobenzoic acid was observed when the sulfate reducing bacterium was cultured alone in a yeast extract amended medium, suggesting that the mutualistic efforts of a mixed population of anaerobes were necessary to efficiently mediate reductive dehalogenation. / Ph. D.