Kung-Hui (Bella) Chu
Associate Professor, Zachary Department of Civil Engineering
Texas A&M University
Kung-Hui (Bella) Chu is an Associate Professor of the Zachry Department of Civil Engineering at Texas A&M University. Dr. Chu's research interests are in environmental biotechnologies. Dr. Chu is an expert on biodegradation/biotransformation of emerging contaminants, development and application of culture-independent methods and bioassys, nutrient removal, as well as biofuel and bioproduct production.
Cometabolic Biodegradation of 1,2,3-Trichloropropane by Propane-Oxidizing Bacteria
1,2,3-Trichloropropane (TCP) is an emerging groundwater pollutant and suspected human carcinogen. TCP has been detected in the subsurface near TCP manufacture facilities and many superfund sites. TCP is also on the EPA’s Contaminant Candidate List 4. While aerobic and anaerobic transformations of TCP are thermodynamically favorable, no environmental isolates capable of using TCP as sole carbon or energy source have been reported. In this study, we investigated the potential of biodegradation of TCP by different monooxygenase-expressing cultures. Specifically, four propane-oxidizing bacteria (PrOB), Rhodococus jostii RHA1, Mycobacterium vaccae JOB5, Rhodococcus rubber ENV425 and one isolated strain Sphingopyxis sp. AX-A, were examined for their ability to degrade TCP via cometabolic reactions. All the four PrOB were able to degrade TCP after growth on propane. Among the four strains, strain JOB5 exhibited the best TCP degradation ability (vinitial = 9.7 ± 0.7 μg TCP (mg protein)-1h-1). No TCP was degraded in the presence of acetylene (a propane monooxygenase (PrMO) inhibitor), suggesting that PrMO might be responsible for TCP degradation. Furthermore, the presence of propane and TCE inhibited biodegradation of TCP. The results of this study suggest that propane-oxidizing bacteria can be used for remediating TCP-contaminated sites.
FLASH POSTER PRESENTATION
Zinc Oxide as a Promising Photocatalyst for Emerging Contaminants Removal
Endocrine disrupting compounds (ECDs), pharmaceuticals and personal care products (PPCPs), disinfection by-products (DBPs), and per- and poly-fluoroalkyl substances (PFASs), are contaminants that have been detected in treated wastewater, source waters, or drinking water. The occurrences of these compounds are of a great health concern as many of these compounds are known carcinogens, or have shown toxicity to laboratory animals. Removal of these contaminants in water is challenging, in part, due to their diverse chemical and physical properties.
Transition metal like zinc oxide (ZnO) has some interesting semiconducting, adsorbing and optical properties. A recent study has reported that ZnO can photodegrade bisphenol A, an EDC. In this study, we examined photodegradation potential of different types of emerging contaminants by ZnO under environmentally friendly conditions, particularly near neutral pH and room temperature. Our experimental results showed that ZnO can effectively photodegrade tricholomethanes (THMs, DBPs), triclosan and triclocarbon (antibiotics, EDCs and PPCPs), 1,4-dioxane (an industrial additives), and 6:2 fluorotelomer alcohol (6:2 FTOH) and 5:3 polyfluorinated acid (5:3 acid, PFASs). Several photodegradation metabolites from 5:3 acid and triclocarbon were also identified. The reusability of ZnO was also investigated. Overall, our results suggest that ZnO is a promising photocatalyst for effective removal of 1,4-dioxane, THMs, triclosan, and 5:3 acid.