Exploitation of extracellular organic matter from Micrococcus luteus to enhance ex situ bioremediation of soils polluted with used lubricants

Chronic pollution by used lubricant oils (ULOs) poses a serious challenge to the environment. Under stress conditions, microorganisms, including potential degraders, can enter viable but non-culturable (VBNC) state, complicating bioremediation of ULO-polluted areas. Resuscitation-promoting factors (Rpfs) reverse this transition and/or enhance biodegradation performance both native and augmented strains. Here, Rpf-containing extracellular organic matter (EOM) from Micrococcus luteus was ex situ ULO removal in biostimulated bioaugmented (with Rhodococcus qingshengii KAG C, R. erythropolis PR4) soils. bioconversion, microbial activity, CFUs were significantly higher EOM-treated soils compared corresponding control After 60 days, initial concentration (52,500 mg kg−1) reduced 37% 45% with EOM-supplemented biostimulation bioaugmentation, respectively. Based on high-throughput 16S rRNA analysis, enhancement attributable reactivation EOM-responsive hydrocarbonoclastic bacterial genera (e.g., Pseudomonas, Comamonas, Stenotrophomonas, Gordonia) long-term positive effect EOM degradative efficacy introduced rhodococci. Ecotoxicological responses revealed that did not correlate decreased soil toxicity. Our findings provide an insight into applicability its effects activity community composition.