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THE GLYCINE AND PROLINE REDUCTASE SYSTEMS: AN EVOLUTIONARY PERSPECTIVE AND PRESCENCE IN ENTEROBACTERIACEAE
Title
THE GLYCINE AND PROLINE REDUCTASE SYSTEMS: AN EVOLUTIONARY PERSPECTIVE AND PRESCENCE IN ENTEROBACTERIACEAE.
Creator
Witt, Joshua, Self, William, University of Central Florida
Abstract / Description
The Glycine and Proline Reduction systems are two of the best characterized selenoenzymes in bacteria and have been found to occur in a wide variety of clostridia . These enzymes are utilized to reduce glycine or D-proline to obtain energy via substrate level phosporylation or membrane gradients, respectively [6, 7]. This includes the pathogens C. difficile and C. botulinum [5, 8]. Strains of C. difficile are activate toxigenic pathways whenever either of these pathways is active within the...
Show moreThe Glycine and Proline Reduction systems are two of the best characterized selenoenzymes in bacteria and have been found to occur in a wide variety of clostridia . These enzymes are utilized to reduce glycine or D-proline to obtain energy via substrate level phosporylation or membrane gradients, respectively [6, 7]. This includes the pathogens C. difficile and C. botulinum [5, 8]. Strains of C. difficile are activate toxigenic pathways whenever either of these pathways is active within the cell [5, 8]. Though evolutionary studies have been conducted on ammonia producing bacteria none has been done to directly characterize these two system by themselves. This includes an understanding of whether or not this system is transferred between organisms, as many of the clostridia that are to be studied are known to have an "open genome." [8, 10] With this information we were able to generate a phylogenic model of the proline and glycine reduction systems. Through this analysis, we were able to account for many clostridial organisms that contain the system, but also many other organisms as well. These included enterobacteriaceae including a strain of the model organism, Escherichia coli. It was further concluded that Glycine Reductase was a much less centralized system and included a wide range of taxa while Proline Reductase was much more centralized to being within the phyla of firmicutes. It was also concluded that the strain of E. coli has a fully functional operon for Glycine Reductase.
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Date Issued
2013
Identifier
CFH0004506, ucf:45149
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFH0004506
Biological Nutrient Removal (BNR) Process Optimization and Recovery of Embedded Energy Using Biodiesel By-product
Title
Biological Nutrient Removal (BNR) Process Optimization and Recovery of Embedded Energy Using Biodiesel By-product.
Creator
Salamah, Sultan, Randall, Andrew, Duranceau, Steven, Chopra, Manoj, University of Central Florida
Abstract / Description
Enhanced biological phosphorus removal (EBPR) as well as biological nitrogen removal require a carbon source to be carried out. Volatile fatty acid (VFAs) (mainly acetic and propionic acids) are the major driving force for EBPR. Many domestic wastewaters have an insufficient amount of VFAs. However, carbon sources such as acetic and propionic acids can be produced using primary solids fermentation process. Due to the cost of VFA production, an external carbon source can be added to the...
Show moreEnhanced biological phosphorus removal (EBPR) as well as biological nitrogen removal require a carbon source to be carried out. Volatile fatty acid (VFAs) (mainly acetic and propionic acids) are the major driving force for EBPR. Many domestic wastewaters have an insufficient amount of VFAs. However, carbon sources such as acetic and propionic acids can be produced using primary solids fermentation process. Due to the cost of VFA production, an external carbon source can be added to the biological nutrient removal (BNR) system that can be fermented to provide the desired VFAs. Glycerol (biodiesel by-product) offers a solution to reduce carbon addition cost if can be fermented to acetic and propionic acid or can be used directly as an external carbon substrate for EBPR and denitrification. Using glycerol in wastewater treatment can also offset the biodiesel plant disposal cost and reduce the BNR chemical cost. The main objective of this study was to optimize the prefermentation process and optimize the BNR system using glycerol as an external carbon source. In this work, Optimization of the prefermentation process using glycerol, mixing, and hydrogen gas addition was evaluated. EBPR performance within an A2O-BNR system was evaluated using either a direct glycerol method to the anaerobic zone or by co-fermentation with primary solids. Also, optimization of the nitrogen removal (specifically denitrification) efficiency of a 5-stage BardenphoTM BNR system using either a direct glycerol method to the second anoxic zone or by co-fermentation with primary solids was evaluated. It was found in this study that glycerol was an efficient external carbon substrate for EBPR as well as biological nitrogen removal. The prefermentation experiment showed that glycerol co-fermentation with primary solids produced significantly higher (p(<)0.05) VFAs than primary solids fermentation alone, even more than the possible value from the added glycerol (427 mg-COD/L). The increased VFAs imply that the glycerol addition stimulated additional fermentation of primary solids. Lowering the prefermenter mixing energy (50 to 7 rpm) resulted in a significant increase in VFAs production (80%). Also, purging the headspace of the prefermenter with hydrogen gas did not lead to more VFAs, but significantly (p(<)0.05) increased the propionic acid to acetic acid ratio by 41%. In the A2O-BNR pilot plant experiment, it was found that glycerol is a suitable renewable external substrate to drive enhanced EBPR as well as denitrification. The results from both locations of glycerol addition (direct vs. fermented) were beneficial to the BNR system. Both systems had similar effluent quality and achieved total nitrogen (TN) and total phosphorus (TP) removals up to 86% and 92% respectively. The 5-stage BardenphoTM BNR experiment investigated the location of glycerol addition (direct vs. fermented) on the performance of denitrification in the second anoxic zone and the overall performance. The results from both systems were that glycerol was beneficial to the BNR system and had virtually similar effluent quality. Both systems achieve complete denitrification and excellent removal of TN and TP up to 95% and 89% respectively. Also, the pilot that received fermented glycerol had significantly higher VFAs loading and lower observed yield. The side-stream prefermenter effluent flowing to the second anoxic reactor did not cause high effluent ammonia (NH3) concentration. In summary, the location at which glycerol was added did not affect effluent quality for nitrogen and phosphorus. However, glycerol addition and mixing energy did impact prefermenter performance and effluent quality.
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Date Issued
2017
Identifier
CFE0006788, ucf:51826
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0006788