Drivers for efficient bioaugmentation and clean-up of contaminated soil

Bioaugmentation constitutes a viable approach for the bioremediation of soils polluted by organic chemicals, but limitations may arise due to the poor in situ performance of the inoculated microorganisms. This chapter examines these – poorly understood – drawbacks in the light of the latest advances in microbial ecology and bioremediation strategies. We discuss how biotic and abiotic factors may compromise the establishment and activity of microbial inoculants in soil, as well as how to design efficient inoculants that exhibit increased robustness and dispersal. Innovative approaches could include taking advantage of microbial networks through bacterial consortia with complementary catabolic capabilities, and fungal- and plant-bacterial associations that provide an enhanced bacterial dispersion in water-unsaturated soil conditions. We also provide recommendations on the most convenient strategies for inoculant production and application, considering their mass production, the optimal dosing ratios and the optimised use of platforms for microbial action in soil, such as solid carriers (e.g. biochar) and plants.