Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in soil environment and cause great environmental concern because of their persistence, toxicity and mutagenicity. Phytoremediation technique is a promising option for the treatment of PAH-contaminated soils. As most of the plant species are sensitive to PAH, therefore they grow slowly and it is difficult to establish sufficient biomass for meaningful soil remediation. Phytoremediation may be facilitated with the judicial use of microorganisms having ACC-deaminase activity. Accelerated ethylene production in response to contaminants’ stress is known to inhibit root growth and could be regarded as major constraint in improving phytoremediation efficiency. Bacteria containing 1-aminocyclopropane-1-carboxylic acid (ACC)-deaminase regulate ethylene levels in plants by metabolizing its precursor ACC into α- ketobutyric acid and ammonia. Plants inoculated with ACC-deaminase-containing bacteria regulate their ethylene levels and resultantly bear an extensive root system. Such proliferation of roots in contaminated soil can lead to more plant biomass, active metabolic processes and ultimately enhanced uptake or degradation of xenobiotics.
To investigate this, bacteria would be isolated from PAH/petroleum contaminated sites. Isolates will be screened for their ability to have ACC-deaminase activity, by ACC metabolism assay. Bacteria containing ACC-deaminase, would also be assayed for their ability to degrade PAH. Isolates having both properties i.e. ACC-deaminase activity and bioremediation potential would be characterized on the basis of physiological and morphological characters. Canola and Alfalfa will be used as a test plant in phytoremediation process. Remediation will be monitored in the soil by extracting and analyzing the soil for carbon compounds.
- Collection of samples from PAH/petroleum contaminated-soils for isolation/analysis.
- Isolation and screening of ACC-deaminase-containing bacteria for bioremediation of PAH/petroleum contaminated soils.
- Assessment of phytoremediation potential of canola and alfalfa in combination with bacteria containing ACC-deaminase activity.
Bacteria were isolated and screened for both properties; i.e. ACC deaminase activity and bioremediation capability. These bacteria were tested in Lab/growth room for growth improvement of canola and alfalfa. To evaluate growth improvement capability of the screened plant growth promoting rhizobacteria (PGPR) in contaminated soil is in progress.