Degradation by Typical Bacteria from Coastal Seawater: the Marine Alpha Cluster
Mary Ann Moran (Dept
of Marine Sciences, Univ of Georgia, Athens, GA, USA)
Georgia Sea Grant College Program (R/AT-6)
- 2/28/01 (complete)
1. To isolate and identify bacteria from the newly-recognized Marine Alpha cluster
that are capable of transforming pulp and paper industry wastes and naturally-occurring
lignins and humic substances.
2. To use molecular techniques to identify and quantify lignin-degrading Marine
Alpha bacteria in coastal Georgia environments, including areas impacted by
pulp industry wastes.
3. To use molecular techniques to quantify lignin-degrading Marine Alpha bacteria
in laboratory enrichment studies using industry wastes and other lignin-related
4. To use microbiological techniques to characterize the physiological abilities
of Marine Alpha isolates, including rates of degradation of pulp mill wastes,
naturally-occurring lignins and humic substances, and other aromatic compounds.
Results from this project are beginning
to provide insights into the identity of marine bacteria involved in the degradation
of aromatic compounds in coastal regions of the southeastern US. Detailed studies
are providing information on the enzymology and organization of a family of
ring-cleavage dioxygenase genes of potential interest for biotechnological and
We have characterized aromatic compound
degradation by culturable marine Alpha bacteria isolated from coastal Georgia
environments. Experiments measured rates of degradation of simple (i.e. single
ring) and complex (i.e. lignin) aromatic compounds. Enzymology-based approaches
were used to characterize activity levels of two important enzymes in the degradation
pathway of aromatic compounds in selected isolates: protocatechuate 3,4 dioxygenase
and catechol 1,2 dioxygenase. These enzymes occupy key, rate-limiting positions
in the pathway for aromatic ring degradation in many prokaryotes. Our coastal
marine bacteria had activity levels comparable to those measure previously for
soil bacteria, including members of the genera Pseudomonas, and Acinetobacteri,
which have served as model organisms for much of the previous microbiological
and biochemical studies of aromatic ring cleavage by prokaryotes.
Ring-cleavage dioxygenases and related
genes have been cloned and sequenced from the two coastal Georgia marine bacteria.
González, J.M., R.E. Hodson and M.A. Moran. 1999. Bacterial populations
in replicate marine enrichment cultures: Assessing variability in abundance
using 16S rRna-based probes. Hydrobiologia. 401:69-75.
Buchan, A., E.
L. Neidle, and M. A. Moran. 2001. Diversity of the ring-cleaving dioxygenase
gene pcaH in a saltmarsh bacterial community. Appl. Env. Microbiol. 67:5801-5809.