Biostimulation

Biostimulation is the modification of an environment to stimulate the metabolic activity and growth of existing biological populations, particularly indigenous microorganisms, to achieve a desired outcome. It emphasizes enhancing the activity of native communities rather than introducing new organisms; such introductions are termed bioaugmentation. Biostimulation is applied in soil, groundwater, wastewater treatment, and other ecosystems where microbial processes influence remediation or nutrient cycling.

Mechanisms include supplying limiting nutrients such as nitrogen and phosphorus to stimulate growth, adjusting redox conditions by providing electron acceptors or donors (for example, oxygen or nitrate) to favor particular metabolic pathways, and optimizing physical conditions such as moisture, temperature, and pH. Additional approaches include dispersing surfactants or co-substrates to improve contaminant availability and leveraging organic amendments to support microbial diversity and activity.

Applications span environmental bioremediation, where biodegradation of hydrocarbons, solvents, and chlorinated compounds is accelerated; wastewater treatment processes that rely on robust microbial communities; and the restoration of degraded soils. In agriculture and land management, biostimulation can influence soil microbial activity and nutrient cycling, though products marketed as biostimulants in farming are often distinct from the remediation concept of biostimulation.

Limitations and considerations include reliance on the reliability and capabilities of native microbes, site heterogeneity, and the risk of generating undesirable byproducts. Effective biostimulation typically requires careful monitoring, site-specific design, and, where appropriate, integration with bioaugmentation or other remediation strategies. Regulatory and environmental assessment frameworks guide its use to avoid unintended consequences.