Bioaugmentation is the deliberate introduction of beneficial microorganisms or microbial consortia into a contaminated environment to accelerate the breakdown or transformation of specific pollutants. Unlike natural attenuation or biostimulation, which rely on existing microbial communities and nutrient amendments, bioaugmentation adds organisms adapted to degrade particular compounds.
Selecting and implementing bioaugmentation strategies
Successful bioaugmentation requires careful selection of microorganisms and an understanding of the environmental conditions that influence their activity. Strains are often isolated from sites with similar contaminants or engineered to enhance metabolic pathways that break down hydrocarbons, chlorinated solvents, pesticides, or other persistent chemicals. The introduced microbes must survive competition with native communities, tolerate pH, temperature, and salinity extremes, and access the contaminant. Inocula may be applied as pure cultures, mixed consortia, or immobilized on carriers to improve survival. Nutrient supplementation and aeration can support microbial growth, but excessive amendment may disrupt indigenous ecosystems. Monitoring is essential to track microbial persistence and degradation rates, and regulators often require risk assessments to evaluate potential ecological impacts.
Applications and case studies
Bioaugmentation has been applied in a variety of settings. In marine and coastal oil spill remediation, hydrocarbon‑degrading bacteria such as Alcanivorax, Pseudomonas, and Rhodococcus have been added to accelerate the breakdown of alkanes and aromatics. Wastewater treatment plants use bioaugmentation with nitrifying or denitrifying bacteria to improve ammonium removal or reduce nitrogen levels in effluents, and anaerobic digesters are sometimes supplemented with methanogenic archaea to stabilize biogas production. In soils contaminated with chlorinated solvents or pesticides, strains like Dehalococcoides and Sphingomonas have been introduced to transform trichloroethene or polycyclic aromatic hydrocarbons. Bioaugmentation can be combined with biostimulation, phytoremediation, or surfactant addition, but its success depends on matching microbial capabilities with site-specific conditions.
Bioaugmentation offers a targeted approach to remediating contaminated environments by supplying microorganisms that can quickly metabolize problematic compounds. When applied judiciously and coupled with careful monitoring, it can shorten cleanup times and reduce reliance on physical or chemical treatments.
Related Terms: Bioremediation, Biodegradation, Biostimulation, Microbial consortium, Bioaugmentation strategies