Bioaugmentation and biostimulation strategies to improve the effectiveness of bioremediation processes

Abstract

Bioremediation, involving bioaugmentation and/or biostimulation, being an economical and eco-friendly approach, has emerged as the most advantageous soil and water clean-up technique for contaminated sites containing heavy metals and/or organic pollutants. Addition of pre-grown microbial cultures to enhance the degradation of unwanted compounds (bioaugmentation) and/or injection of nutrients and other supplementary components to the native microbial population to induce propagation at a hastened rate (biostimulation), are the most common approaches for in situ bioremediation of accidental spills and chronically contaminated sites worldwide. However, many factors like strain selection, microbial ecology, type of contaminant, environmental constraints, as well as procedures of culture introduction, may lead to their failure. These drawbacks, along with fragmented literature, have opened a gap between laboratory trials and on-field application. The present review discusses the effectiveness as well as the limitations of bioaugmentation and biostimulation processes. A summary of experimental studies both in confined systems under controlled conditions and of real case studies in the field is presented. A comparative account between the two techniques and also the current scenario worldwide for in situ biotreatment using bioaugmentation and biostimulation, are addressed.

Cutting Edge: IL-17–Secreting Innate Lymphoid Cells Are Essential for Host Defense against Fungal Infection

“…When effective, bioremediation is a cheaper and more sustainable approach to decontamination. Bioaugmentation, the addition of targeted microbial isolates to nonsterile soils, has had various impacts on bioremediation and has generally not increased the abundance of the added organisms over the long term (4)(5)(6)(7)(8). In contrast to single isolate additions, high-throughput sequencing now allows us to explore the extent to which we can modify complex soil microbiomes.…”

Soil health: looking for suitable indicators. What should be considered to assess the effects of use and management on soil health?

“…Landfarming aiming at microbial degradation of the organic fraction of petrochemical residues is an example of soil use as an efficient bioreactor (Dua et al, 2002;Tyagi et al, 2011). Nevertheless, presence of heavy metals, salts and recalcitrant compounds sometimes leads to reduction of soil microbial activity.…”

Biotechnological advances in bioremediation of heavy metals contaminated ecosystems: an overview with special reference to phytoremediation

“…Bioaugmentation is the addition of pre-grown microbial cultures indigenous or exogenous to the contaminated sites to enhance the degradation of unwanted compounds (Tyagi et al 2011). Exogenous cultures rarely compete well enough with an indigenous population to develop and sustain useful population levels, and most soils with long-term exposure to biodegradable waste have indigenous microorganisms that are effectively degraded if the land treatment unit is well managed (USEPA 2004;Kumar et al 2011b).…”

“…However, lack of information about the growth and metabolism of microorganisms in the polluted environment often limits its implementation. Recent advances in the understanding of biogeochemical processes and genomics have opened up new perspectives toward new opportunities of pollution abatement (Chauhan and Jain 2010;Jeffries et al 2012;Rayu et al 2012;Tyagi et al 2011). In order for considerable aerobic biodegradation to occur, however, sufficient amounts of dissolved oxygen must exist within the subsurface to serve as an electron acceptor (Adams and Reddy 2003).…”