Juergen Wiegel

Professor Wiegel, a certified horticulturist (1959, Hannover, Germany),received his Dipl. chem. (M.S. degree in organic chemistry) in 1969, Dr.rer. nat. (Ph.D. degree) in 1973 and Dr. habil. (D.Sc.) in Microbiologyin 1982 from the University of Göttingen, Germany, where he also was employed as a research scientist until 1984. During 1977-1979 he was a visiting postdoctoral fellow in the Department of Biochemistry at the University of Georgia. In 1982 he joined the faculty of the Department of Microbiology at the University of Georgia.

Our research focuses on two major aspects of anaerobic (eu)bacteria:(1) The diversity of anaerobic thermophilic (eu)bacteria (ecological, physiological, molecular and  biochemical aspects); and (2) the microbiology and biochemistry of anaerobic bacteria involved in the anaerobic degradation of chlorinated aromatic compounds including reductive dechlorination of chlorophenols and PCBs and the nonoxidative decarboxylation of  hydroxybenzoates.

Thermophiles. Our interest includes the isolation and characterization of new bacteria from a wide range of environments and locations. We study their major physiological   properties, clone and sequence genes coding for selected enzymes of industrial interest, which we isolate and characterize. Recent examples include hemicellulolytic and xylose-utilizingenzymes (xylanase, xylose[glucose] isomerase, acetyl(xylan)esterase) from Thermoanaerobacterium species. Furthermore, special attention is given to members of our novel group, the alkali-thermophiles (Clostridiumparadoxum, sp. nov.; pH_max^25°C 11.3, T_optof 60°C; and Thermobrachium celere with doubling times at pH 9.5 and60°C of around 10 min) as well as to novel iron(III)-reducing thermophiles (e.g., Thermoterrabacterium ferrireducens). We are working on the development of a genetic system for our thermophilic anaerobes.

Degradation of halogenated aromatic compounds.  We are interested in the influences of environmental parameters on the dechlorination of chlorophenols and PCBs and the microbial interactions among the dehalogenating microbial communities. Based on inhibition studies and enrichment cultures, we postulated the sequential degradation of  2,4-dichlorophenol to methane and CO_2.  Subsequently we isolated members of this postulated chain including Desulfitobacterium dehalogenans gen.nov. spec. nov., able to dechlorinate chlorophenols and related compounds and Clostridium hydroxybenzoicum, sp. nov., a novel phenol carboxylating heterotroph.  We purified and characterized the novel hydroxybenzoatedecarboxylating and phenol/catechol carboxylating enzymes and sequenced the encoding gene for the 4-HO-benzoate DC, which has high similarities to several hypothetical proteins identified in genome sequences. 

 "Advances in the development of a genetic system for Thermoanaerobacterium: Expression of genes encoding hydrolytic enzymes, development of a second shuttle vector and integration of genes into the chromosome," Mai, V.;  Wiegel, J.  Appl. Environ. Microbiol. 2000, 66, 4817-4821.

 "Caloramator viterbensis sp. nov., a novel thermophilic glycerol-fermenting bacterium isolated form a hot spring in Italy," Seyfried, M.; Lyon, D.; Rainey, F. A.; and Wiegel, J. Int J Syst Evol Microbiol. 2002, 52, 1177-1184.

E-mail contact:
jwiegel@arches.uga.edu 

Website: 
http://www.uga.edu/mib/jwiegel/html