Progress 06/14/02 to 06/13/08
Outputs
OUTPUTS: This project has focused on two primary areas of research during the past 12 years: improvement of anaerobic digestion processes for production of biogas as an energy resource and development of immobilized microbial systems for bioremediation of hazardous chemicals. With respect to anaerobic digestion processes, the focus was on conversion of dairy manure. Projects included investigation of methods to enhance biogas production under low-temperature (psychrophilic) conditions, renovation of an anaerobic digester located at a commercial dairy, analysis of biogas production from a covered lagoon at a commercial dairy, and development of a small-scale demonstration thermophilic digester. We also conducted energy audits for several commercial dairies in Texas and California to assess potential for manure-to-energy conversion processes. With respect to bioremediation processes, we investigated systems of immobilized bacterial cultures for degradation of organophosphate pesticides. These studies together provided thesis topics for 3 M.S. students and 3 Ph.D. students. In addition, these studies provided training for one postdoctoral student. Results from these studies provided the basis for 11 refereed journal articles and 18 conference papers. PARTICIPANTS: 3 M.S. students, 3 Ph.D. students and 1 postdoctoral student received training from this project. TARGET AUDIENCES: Target audiences include engineers and scientists involved in production of biogas by anaerobic digestion or in biodegradation of hazardous chemicals and dairy producers concerned with adding value to animal waste through production of biogas. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Anaerobic digester reactors packed with pieces of non-woven polyester matting had greater methane yield and biogas productivity than control reactors with no packing when operated at both 35 C and 10 C; however, productivity at 10 C was only about 25% of that at 35 C. Survey studies of solid-phase anaerobic composting of animal manure which indicated there is potential for this type of process but considerable work remains to implement it. Energy audits were conducted for several commercial dairies in Texas and California to assess the potential for manure to energy conversion processes. Data were collected for energy usage in terms of electrical, diesel fuel, propane, natural gas and gasoline as well as for type of manure handling system. The greatest amount of energy used at all dairies was electrical, followed by liquid and gaseous fuels. Generally, newer dairies were more efficient in electrical energy use than their older counterparts, indicating that a significant amount of energy might be saved by upgrading facilities with new, more energy efficient equipment. Studies of immobilized bacteria, both pure and mixed cultures, showed that immobilized cultures have higher specific activity (amount of degradation per gram of organisms) than freely suspended organisms and are not subject to inhibitory factors that affect freely suspended cells. This was shown to be true for several different immobilized systems. An immobilized recombinant strain of Escherichia coli was shown to effectively hydrolyze coumaphos, an organophosphate pesticide, to chlorferon and diethylthiophosphate (DETP). Further studies showed that immobilized consortia of bacteria enriched from waste coumaphos treatment facilities were effective for degrading both chlorferon and DETP. In all cases, immobilized cultures were more effective for degradation and could be reused several times without losing any activity.
Publications
- Ha, Jiyeon, C.R. Engler and J.R. Wild. 2009. Biodegradation of coumaphos, chlorferon, and diethylthiophosphate using bacteria immobilized in Ca-alginate gel beads. Bioresource Technol. 100: 1138-1142. http://dx.doi.org/10.1016/j.biortech.2008.08.022.
- Ha, Jiyeon, C.R. Engler and S.J. Lee. 2008. Determination of diffusion coefficients and diffusion characteristics for chlorferon and diethylthiophosphate in ca-alginate gel beads. Biotechnol. Bioeng. 100(4): 698-706. http://dx.doi.org/10.1002/bit.21761.
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Progress 01/01/07 to 12/31/07
Outputs
OUTPUTS: Energy audits were conducted for several commercial dairies in Texas and California to assess the potential for manure to energy conversion processes. Data were collected for energy usage in terms of electrical, diesel fuel, propane, natural gas and gasoline as well as for type of manure handling system. Data currently are being analyzed. Initial design parameters for a small-scale thermophilic anaerobic digester were completed. This digester will be skid mounted so it can be transported by trailer to commercial dairies to demonstrate biogas production.
PARTICIPANTS: 1. Engler, C.R., PI. 2. Training provided for 1 undergraduate student, P. Gieger, Jr.
TARGET AUDIENCES: Producers who have potential for utilizing animal manure as an energy resource through anaerobic digestion for biogas production.
Impacts
Data collected during the reporting period currently are being analyzed and will be reported during the next reporting period.
Publications
- Ha, Jiyeon, C.R. Engler and J.R. Wild. 2007. Biodegradation of Chlorferon and Diethylthiophosphate by Consortia Enriched from Waste Cattle Dip Solution. Bioresource Technol. 98(10): 1916-1923.
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Progress 01/01/06 to 12/31/06
Outputs
Work focused on characterization of biogas production from a covered anaerobic lagoon at a commercial dairy. A methane analyzer was purchased and installed at the dairy to monitor the methane content of the biogas being produced. Preparations are being made to conduct energy audits of commercial dairies in Texas to assess the potential for manure to energy conversion processes.
Impacts
Development of more efficient bioprocesses will improve the economic outlook for production of fuels and chemicals from biomass and for remediation of environmental hazards.
Publications
- Ha, Jiyeon, C.R. Engler and J.R. Wild. 2007. Biodegradation of Chlorferon and Diethylthiophosphate by Consortia Enriched from Waste Cattle Dip Solution. Bioresource Technol. 98(10): 1916-1923.
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Progress 01/01/05 to 12/31/05
Outputs
Work focused on biodegradation of the hydrolysis products of coumaphos, an organophosphate pesticide. Enrichment cultures of cells for degradation of diethyl thiophosphate (DETP) and chlorferon, the hydrolysis products of coumaphos, were developed previously. Methods were developed to produce active biomass for each culture and immobilize it in calcium alginate beads. The immobilized cells were found to be more active for degradation of the target chemicals than freely suspended cells.
Impacts
The processes being developed can be used to rapidly degrade hazardous chemicals that contaminate the environment. These processes also may be adapted for conversion of wastes into valuable products.
Publications
- Ha, Jiyeon, Bioremediation of the Organophosphate Pesticide, Coumaphos, using Microorganisms Immobilized in Calcium-Alginate Gel Beads, Ph.D. Dissertation, Texas A&M University, December 2005
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Progress 01/01/04 to 12/31/04
Outputs
Work focused on biodegradation of the hydrolysis products of two organophosphate pesticides, coumaphos and methyl parathion. Work on degradation of p-nitrophenol (PNP) by a pure culture of Sphingobium chlorophenolicum was completed. Results indicated that degradation of PNP occurs only when the culture is growing on another carbon source. Also, degradation of PNP was incomplete when initial concentrations were greater than 100 mg/L. Degradation of diethyl thiophosphate (DETP) and chlorferon, the hydrolysis products of coumaphos, was studied using enrichment cultures developed for each compound. Chlorferon degradation was subject to substrate inhibition but was not affected by the presence of DETP. Degradation of DETP was not inhibited by substrate but was strongly inhibited by chlorferon. In addition to the degradation studies, methods for immobilizing cells were evaluated.
Impacts
The processes being developed can be used to rapidly degrade hazardous chemicals that contaminate the environment. These processes also may be adapted for conversion of wastes into valuable products.
Publications
- Diaz Casas, Adriana Z., Bioremediation of the Organophosphate Methyl Parathion using Genetically Engineered and Native Organisms, M. S. Thesis, Texas A&M University, August 2004
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Progress 01/01/03 to 12/31/03
Outputs
Work focused on biodegradation of the hydrolysis products of two organophosphate pesticides, coumaphos and methyl parathion. Initial hydrolysis of both compounds is accomplished using a recombinant strain of E. coli that produces organophosphate hydrolase. Conditions for degradation of p-nitrophenol by a pure culture of Sphingobium chlorophenolicum were developed, and cultures capable of degrading diethyl thiophosphate and chlorferon were isolated from cattle dip waste solutions. Methods for utilizing these cultures for biodegradation processes currently are being developed..
Impacts
The processes being developed can be used to rapidly degrade hazardous chemicals that contaminate the environment. These processes also may be adapted for conversion of wastes into valuable products.
Publications
- Diaz, A.Z., J. Ha, J.R. Wild and C.R. Engler. 2003. Methyl parathion degradation by recombinant Escherichia coli, Paper No. 037033, ASAE Annual International Meeting, Las Vegas, NV, July 27-30.
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Progress 01/01/02 to 12/31/02
Outputs
Work focused on biodegradation of two organophosphate pesticides, coumaphos and methyl parathion. Initial degradation of both compounds is accomplished using a recombinant strain of E. coli that produces organophosphate hydrolase. Conditions for hydrolysis of each compound were evaluated. In addition, evaluation of bacteria selected for degradation of hydrolysis products from these pesticides was initiated. HPLC methods were selected for analysis of the pesticides and their degradation products. Analytical conditions were optimized for the compounds of interest.
Impacts
Processes based on immobilized consortia of organisms could be used to rapidly degrade hazardous chemicals that contaminate the environment. Such processes also could be used for conversion of raw materials or wastes into valuable products.
Publications
- Kim, J.-W., E.I. Rainina, W.W. Mulbry, C.R. Engler and J.R. Wild. 2002. Enhanced-rate biodegradation of organophosphate neurotoxins by immobilized non-growing bacteria. Biotechnol. Progress 18(3): 429-436.
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Progress 01/01/01 to 12/31/01
Outputs
Work on biodegradation of organophosphate pesticides using immobilized cells continued. Work completed has focused on use of a pure culture of genetically engineered bacteria to hydrolyze coumaphos, the pesticide used in cattle dip vats in South Texas. This is only the first step in the biodegradation process. In the current work we are developing immobilized consortia of organisms to degrade organophosphates to environmentally benign compounds. We are continuing to work on degradation of coumaphos and are also evaluating degradation of methyl parathion.
Impacts
Immobilized consortia of organisms potentially could rapidly degrade hazardous chemicals to environmentally benign compounds.
Publications
- Sterling, M.C., Jr., R.E. Lacey, C.R. Engler and S.C. Ricke. 2001. Effects of ammonia nitrogen on H2 and CH4 production during anaerobic digestion of dairy cattle manure. Bioresource Technol. 77(1): 9-18.
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Progress 01/01/00 to 12/31/00
Outputs
Bioprocess engineering work continued in the areas of anaerobic digestion of animal manure and bioremediation of hazardous chemicals. Preliminary studies on anaerobic composting of feedlot manure were completed indicating there is potential for a solid state anaerobic digestion process. Considerable work remains to implement such a process. Additional studies were conducted to determine the potential for anaerobic digestion of paper mill sludge. Results were positive but further work is needed to determine nutrient requirements for optimum yields from the process. In the area of bioremediation, a manuscript describing results from degradation of coumaphos, an organophosphate pesticide, using immobilized non-growing bacteria was submitted for publication.
Impacts
Development of an anaerobic composting process could provide a method to effectively capture significant amounts of energy in the form of methane gas from feedlot manure, and anaerobic digestion of paper mill sludge could turn a waste disposal problem into an energy resource. Immobilized non-growing cell bioremediation processes could provide rapid degradation of hazardous materials.
Publications
- Classen, J.J., C.R. Engler, C.M. Kenerley and A.D. Whittaker. 2000. A logistic model of subsurface fungal growth with application to bioremediation. J. Environ. Sci. Health, Part A A35(4): 465-488.
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Progress 01/01/99 to 12/31/99
Outputs
Bioprocess engineering work continued in the areas of anaerobic digestion of animal manure and bioremediation of hazardous chemicals. Work was completed on renovation of an anaerobic digester located at the Carrell Dairy in Godley, TX, and it was turned over to the owner for operation. Unfortunately, the owner did not maintain flow of manure to the system and it did not become operational. Preliminary studies on anaerobic composting of manure were begun. These studies are to determine the potential for solid state digestion of manure to produce biogas. In the area of bioremediation, the dynamic diffusion-reaction model for degradation of thiodiglycol by immobilized cells was published, and the model was further developed to describe degradation of sparingly soluble compounds.
Impacts
The goal of work on anaerobic composting is to develop a more suitable system for converting feedlot manure to an energy resource. The goal of our work on bioremediation is to develop a process for rapid degradation of hazardous wastes.
Publications
- Kim, J.-W., E.I. Rainina, C.R. Engler and J.R. Wild. 1999. Processing efficiency of immobilized non-growing bacteria: biocatalytic modeling and experimental analysis. Can. J. Chem. Eng. 77(5): 883-892.
- Vartak, D.R., C.R. Engler, S.C. Ricke and M.J. McFarland. 1999. Low Temperature Anaerobic Digestion Response to Organic Loading Rate and Bioaugmentation. J. Environ. Sci. Health, Part A A34(3): 567-583.
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Progress 01/01/98 to 12/31/98
Outputs
One objective of this project has been to renovate an anaerobic digester located at a commercial dairy to demonstrate this technology as an alternative means of disposing of animal waste while recovering energy in the form of biogas as a byproduct. The digester renovation was completed and initial loading of manure slurry into the digester begun. The digester is now in the start-up phase in which the digester temperature will be increased to its operating value of 95 degrees F and continuous feeding of manure initiated. Operating results will be collected during the next year. The biogas produced will be used to fuel a generator to provide electricity for the dairy. Once fully operational, the dairy should be self-sufficient for electricity. Another objective of this project has been to evaluate the use of immobilized non-growing bacteria for biodegradation of coumaphos, the active insecticide ingredient in cattle dip. A recombinant Escherichia coli strain containing
genes for expression of the organophosphate hydrolase enzyme was used since this enzyme catalyzes the initial step in coumaphos degradation. Rate studies for the immobilized cells showed they had higher specific activity than freely suspended cells and were not subject to inhibitory factors that affected the freely suspended cells. Continued work on biodegradation of thiodiglycol (TDG) showed that optimal conditions for non-growing cells immobilized in a macroporous carrier (poly (vinyl alcohol) cryogel)were the same as for non-growing freely suspended cells. Therefore, experimental data from freely suspended cells can be used in designing immobilized cell systems. In addition, a dynamic diffusion-reaction model was developed and validated using experimental data for TDG degradation by Alcaligenes xylosoxidans sugsp. xylosoxidans immobilized in the cryogel.
Impacts
(N/A)
Publications
- Vartak, D.R., Engler, C.R., Ricke, S.C., McFarland, M.J. and Byers, F.M. 1998. Mesophilic performance of attached-film reactors subject to low temperature stress. Transactions of the ASAE 41(5):1463-1468.
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Progress 01/01/97 to 12/31/97
Outputs
Anaerobic lagoons undergo seasonal variations in temperature which cause rates of digestion to vary substantially. One of the objectives in this project was to study the recovery of laboratory anaerobic digesters subjected to a temperature cycle from warm (37 deg. C) to cold (10 deg. C) and back to warm conditions. Six digesters were maintained in an environmental chamber, with the temperature varied between 37 and 10 deg. C. Two digesters were packed with limestone gravel, two with pieces cut from non-woven polyester matting, and two had no packing. Two additional reactors with no packing were maintained at a constant 37 deg. C for the same period. Biogas production for the period after temperature cycling was lower for all reactors, including the controls that were not subjected to temperature cycling; however, since the percentage change was about the same, it appears that all reactors undergoing the temperature cycle regained their activity when the temperature
was brought back to 37 deg. C. The reactors with polyester packing and those without packing had about the same biogas productivities and yields, while the reactors with limestone packing had significantly lower productivity and yield. The acidogenic and methanogenic microbial populations apparently had similar responses to changes in temperature because there was little accumulation of VFAs as temperature was lowered and rapid increases in daily biogas production as temperature was raised. The polyester packing retained about 10 times more biomass within its structure than did the limestone packing. Both types of packing retained biomass within the spaces between packing particles which was not included in retention analyses. Another objective of this project was to investigate the use of immobilized cells for biodegradation of thiodiglycol (TDG), one of the hydrolysis products of sulfur mustard gas (a chemical warfare agent). A subspecies of Alcaligenes xylosoxidans was immobilized
in poly(vinyl) alcohol cryogels which formed as spherical granules with a diameter of 0.5 mm. The immobilized cells were capable of rapid degradation of TDG in tap water or potassium phosphate buffer (100 mM, pH 8.0) containing ammonium sulfate. The immobilized cells did not show any substrate inhibition up to 200 mM TDG and retained 100 percent activity during three months of continuous use.
Impacts
(N/A)
Publications
- Kim, J.-W., E.I. Rainina, E. Efremenko, C.R. Engler and J.R. Wild. 1997. Degradation of thiodiglycol, the hydrolysis product of sulfur mustard, with bacteria immobilized within poly(vilyl) alcohol cryogels. Biotechnol. Letters 19(11):1067-1071.
- Vartak, D.R., C.R. Engler, M.J. McFarland and S.C. Ricke. 1997. Attached-film media performance in psychrophilic anaerobic treatment of dairy cattle wastewater. Bioresource Technology 62(3):79-84.
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Progress 01/01/96 to 12/30/96
Outputs
Methanogenesis has been observed at temperatures as low as 4deg.C. In anaerobic lagoons the rate of methanogenesis is greatly reduced or ceases completely as temperatures drop into the psychrophilic range during the winter months. Retention of microorganisms by providing an attachment medium in anaerobic treatment systems potentially can increase their productivity at lower operating temperatures, reducing pollution & odor potential & allowing economic recovery of methane as an energy resource. The objective was to investigate the effectiveness of attached-film bioreactors for psychrophilic anaerobic digestion of dairy manure. Eight digesters were maintained in an environmental chamber, with temperature varied between 37 & 10deg.C. Two digesters were packed with limestone gravel, 2 with pieces cut from non-woven polyester matting, 2 with a combination of limestone gravel & polyester pieces, & 2 had no packing. Digester operation was initiated at a temperature of
37deg.C. After the digesters reached stable operation at the initial temperature, it was lowered slowly to 10deg.C. Best overall conversion of substrate to methane at both 37deg.C & 10deg.C was obtained with the polyester medium, & it also provided the greatest volatile solids reduction at 37deg.C. Methane yields & specific productivities for all attached-film reactors were slightly better than the controls at 10deg.C. Productivities of systems under psychrophilic conditions were about 25% of those obtained under mesophilic conditions.
Impacts
(N/A)
Publications
- Vartak, D.R., Engler, C.R.,, McFarland, M.J., and Ricke, S.C. 1996. Performance of media types in psychrophilic anaerobic treatment of dairy wastewater in attached film packed bed reactors. Proceedings of the Seventh National Bioenergy Conf.
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