Environmental restoration using plant-microbe bioaugmentation

Conference · Thu Apr 01 04:00:00 EST 1993

OSTI ID:6591767

Kingsley, M T; Metting, F B; Fredrickson, J K; Seidler, R J

Land farming, for the purpose of bioremediation, refers traditionally to the spreading of contaminated soil, sediments, or other material over land; mechanically mixing it; incorporating various amendments, such as fertilizer or mulch; and sometimes inoculating with degradative microorganisms. Populations of bacteria added to soils often decline rapidly and become metabolically inactive. To efficiently degrade contaminants, microorganisms must be metabolically active. Thus, a significant obstacle to the successful use of microorganisms for environmental applications is their long-term survival and the expression of their degradative genes in situ. Rhizosphere microorganisms are known to be more metabolically active than those in bulk soil, because they obtain carbon and energy from root exudates and decaying root matter. Rhizosphere populations are also more abundant, often containing 10[sup 8] or more culturable bacteria per gram of soil, and bacterial populations on the rhizoplane can exceed 10[sup 9]/g root. Many of the critical parameters that influence the competitive ability of rhizosphere bacteria have not been identified, but microorganisms have frequently been introduced into soil (bioaugmentation) as part of routine or novel agronomic practices. However, the use of rhizosphere bacteria and their in situ stimulation by plant roots for degrading organic contaminants has received little attention. Published studies have demonstrated the feasibility of using rhizobacteria (Pseudomonas putida) for the rapid removal of chlorinated pesticides from contaminated soil, and to promote germination of radish seeds in the presence of otherwise phytotoxic levels of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D), and phenoxyacetic acid (PAA). The present investigation was undertaken to determine if these strains (Pseudomonas putida PP0301/pRO101 and PP0301/pRO103) could be used to bioremediate 2,4-D-amended soil via plant-microbe bioaugmentation.

• Research Organization: Pacific Northwest Lab., Richland, WA (United States)
• Sponsoring Organization: DOE; USDOE, Washington, DC (United States)
• DOE Contract Number: AC06-76RL01830
• OSTI ID: 6591767
• Report Number(s): PNL-SA-22251; CONF-930482--6; ON: DE93013160
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540220* -- Environment
Terrestrial-- Chemicals Monitoring & Transport-- (1990-)
550700 -- Microbiology
59 BASIC BIOLOGICAL SCIENCES
AUGMENTATION
BACTERIA
BIODEGRADATION
CARBON DIOXIDE FIXATION
CHEMICAL REACTIONS
DECOMPOSITION
GROWTH
LAND RECLAMATION
MICROORGANISMS
NITROGEN FIXATION
OPTIMIZATION
PESTICIDES
PLANT GROWTH
PSEUDOMONAS
RHIZOBIUM
SOILS
SURVIVAL TIME