Table 1.
Overview of recent studies regarding hydrocarbon biodegradation strategies.
| Bioremediation Strategy |
Contaminants | Test System |
Removal Efficiency |
Process Duration | Conclusions/Comments | Reference |
|---|---|---|---|---|---|---|
| Autochthonous bioaugmentation | Alkanes(initial concentration not specified) | Drill cuttings microcosms | 35–66% | 12 weeks | Consortia were isolated from drill cuttings, enriched and reintroduced. The consortia exhibited a high biodegradation potential towards several hydrocarbon substrates and the ability to produce biosurfactants. Enrichment of Firmicutes was observed. |
Guerra et al. 2018 [34] |
| Autochthonous bioaugmentation | Phenanthrene (10 mg/L) |
Bottle tests | >90% | 6 days | Autochthonous bioaugmentation allowed to improve the biodegradation efficiency. The re-introduced autochthonous isolate did not directly participate in the biodegradation process, and the improvement was attributed to altered diversity of PAH degraders. | Li et al. 2018 [35] |
| Autochthonous bioaugmentation | Crude oil (10–50 g/kg) |
Composting | 60–91% | 12 weeks | Re-introduction of two autochthonous isolates into the population allowed for successful bioaugmentation and improvement of the biodegradation process. | Koolivand et al. 2019 [36] |
| Bioaugmentation | Crude oil (TPH at 12 g/kg) |
Soil microcosms | 30–38% | 182 days | The bioaugmentation initially improved the biodegradation efficiency; however, after 91 days, a significant decrease of soil respiration was observed with changes of the bacterial community composition. | Pacwa-Płociniczak et al. 2019 [37] |
| Bioaugmentation | Diesel oil and diesel/biodiesel blends (1% v/w) |
Soil microcosms | 88–97% | 64.5 weeks | Bioaugmentation initially improved the biodegradation kinetics; however, there was no significant effect in the long term. Furthermore, the ratio of aliphatic to aromatic fractions remained unchanged regardless of the treatment used. | Woźniak-Karczewska et al. 2019 [38] |
| Bioaugmentation + biosurfactant/surfactant-assisted biodegradation | Pyrene (10 mg/kg) |
Soil microcosms | 60% | 10 days | Bioaugmentation was successful. High biodegradation efficiency was observed in the case of unamended and surfactant (Brij-35)-amended soil samples. Supplementation with rhamnolipids inhibited the biodegradation process due to their utilization as a preferential carbon source. |
Wolf and Gan 2018 [39] |
| Bioaugmentation + biostimulation | PAHs (1.5 g/kg) |
Soil mesocosms | 99% | 56 days | Biostimulation successfully improved the biodegradation efficiency, whereas bioaugmentation did not significantly contribute to the process. Enrichment of the community in PAH-degrading species was observed. |
Haleyur et al. 2019 [40] |
| Bioaugmentation + biostimulation | Crude oil (TPH at 20 g/kg) |
Soil microcosms | 36–51% | 30 days | The highest biodegradation efficiency was achieved when bioaugmentation was carried out using an immobilized bacterial consortium, with Eichhornia crassipes dried straw acting as both a carried and additional source of C and N. | Tao et al. 2019 [41] |
| Bioaugmentation + biostimulation | Crude oil (TPH at 19.8 g/kg) |
Soil microcosms | 28% (biostimulation) and 14% (bioaugmentation) | 12 weeks | Biostimulation allowed to achieve superior efficiency compared to bioaugmentation. Application of bioaugmentation resulted in notably decreased biodiversity of the soil community. |
Wu et al. 2019 [42] |
| Bioaugmentation + biostimulation + surfactant-assisted biodegradation | Diesel oil hydrocarbons (3 g/kg) + PAHs (400 µg/kg) | Weathered oily-soil biopiles | 39% for diesel oil hydrocarbons and 32% for PAHs | 160 days | Combined bioaugmentation, biostimulation and surfactant supplementation (Tween 80) improved the biodegradation efficiency. In case of biostimulation, ammonium nitrate facilitated the process, whereas the use of urea inhibited the biodegradation efficiency. | Oualha et al. 2019 [43] |
| Biostimulation + surfactant-assisted biodegradation | Crude oil (either 20 g/kg or 50 g/kg) | Field study in soil | 49–62% | 486 days | Biostimulation improved the biodegradation efficiency in all experimental variants. Surfactant supplementation (Bioversal) improved the biodegradation process in cases of higher concentration of crude oil, whereas in cases of lower concentrations, it did not significantly affect the process. | Ortega et al. 2018 [44] |
| Biosurfactant-assisted biodegradation | Phenanthrene (0.1–1.0 mg/L) |
Sorption reactors with soil | >90% | Up to 50 days | Supplementation of the biosurfactant (rhamnolipids) influenced the sorption kinetics of phenanthrene; however, it had no effect on its biodegradation kinetics. No significant influence of the biosurfactant on the main phenanthrene degraders was observed. |
Crampon et al. 2017 [45] |
| Biosurfactant-assisted biodegradation | Hexadecane (2% v/v) |
Flask studies | 20–100% | 180 h | The biosurfactant (rhamnolipids) increased the availability of hexadecane in the case of Pseudomonas aeruginosa (which was capable of producing rhamnolipids) and decreased the availability in the case of Pseudomonas putida (which was unable to produce rhamnolipids). The decrease occurred due to a blocking effect by rhamnolipids. Dissipation of rhamnolipids was also observed. |
Liu et al. 2017 [46] |
| Biosurfactant-assisted biodegradation | Crude oil (1% v/v) |
Flask studies | >85% | 14 days | Isolates from beach sediments exhibited the ability to efficiently degrade hydrocarbons and produce biosurfactants. The biosurfactants increased the emulsification of crude oil and facilitated the biodegradation process. | Lee et al. 2018 [47] |
| Biosurfactant-assisted biodegradation | Phenanthrene (0.2–1.0 mg/L) | Flask studies | 60–100% | 14 days | The biosurfactant (rhamnolipids) was supplemented in order to improve the biodegradation efficiency. At a concentration of up to 100 mg/L of rhamnolipids, an enhancement of phenanthrene biodegradation was observed. At concentrations higher than 200 mg/L of rhamnolipids, the biodegradation efficiency was decreased due to the hindered biosorption of phenanthrene. |
Ma et al. 2018 [48] |
| Biosurfactant-assisted biodegradation | PAHs: phenanthrene, fluoranthene, and pyrene (6 mg/kg) | Soil microcosms | 72% for phenanthrene, 64% for fluoranthene, and 58% for pyrene at day 7 |
up to 35 days | Supplementation with the biosurfactant (rhamnolipids) initially increased the biodegradation of the studied PAHs (at day 7); however, no effect or even lower efficiency were observed in the latter stages (up to 35 days). | Lu et al. 2019 [49] |
| Biosurfactant/surfactant-assisted biodegradation | Fluorene (280 or 320 mg/L) |
Flask studies | 75–97% | 24 h | Supplementation with the biosurfactant (rhamnolipids) allowed to achieve higher biodegradation efficiency compared to synthetic surfactants (Tween-80, Tween-60, Tween-40, Tween-20 and Triton X-100). | Reddy et al. 2018 [50] |
| Biosurfactant/surfactant-assisted biodegradation | Diesel oil (1% v/v) |
Flaks studies | 20–99% | 7 days | Surfactant supplementation (Tween-80) enhanced the biodegradation of diesel oil hydrocarbons. Supplementation with the biosurfactant (rhamnolipids) inhibited the biodegradation process due to their utilization as a preferential substrate. |
Staninska-Pięta et al. 2019 [51] |
| Natural attenuation + autochthonous bioaugmentation | Diesel oil (1% v/v) |
Flask tests | 20–40% | 7 days | Efficiency of biodegradation processes with autochthonous bioaugmentation depended on the previous exposure of soils to pollution. In the majority of tested systems, the autochthonous bioaugmentation resulted in a significant enrichment of Proteobacteria. | Czarny et al. 2019 [52] |
| Natural attenuation + bioaugmentation + biostimulation | Engine oil (39–41 g/kg TPH) |
Soil microcosms | 31–75% | 210 days | The combined bioaugmentation and biostimulation approach resulted in the inhibition of biodegradation processes in comparison to natural attenuation. | Ramadass et al. 2018 [53] |
| Natural attenuation + bioaugmentation + biostimulation | Petroleum refinery waste (TPH at 144 g/kg) | Vial microcosms | 57–75% | 120 days | Combined bioaugmentation-biostimulation approach allowed to achieve the best biodegradation efficiency. Biostimulation was the major driving force for the enhancement. |
Roy et al. 2018 [54] |
| Natural attenuation + bioaugmentation + biostimulation | Crude oil (20 g/kg) |
Bioreactors with soil | 51–90% | 60 days | The combined bioaugmentation and biostimulation approach allowed to achieve the highest biodegradation rate. Among individual treatments, the efficiency of biostimulation was superior (82% of TPH removal) compared to bioaugmentation (63% of TPH removal). |
Safdari et al. 2018 [55] |
| Natural attenuation + bioaugmentation + biostimulation | Crude oil (3% w/v) |
Soil microcosms | 94% | 45 days | Combined bioaugmentation and biostimulation allowed to achieve the most rapid and efficient biodegradation process. | Varjani and Upasani 2019 [56] |
| Surfactant-assisted biodegradation | PAHs (574 mg/kg) |
Soil microcosms | 72–77% | 84 days | Enhanced biodegradation was observed at sub-CMC concentrations of the surfactant (Triton X-100), whereas decreased efficiency was observed at CMC concentrations. The negative effect may be attributed to the preferential degradation of surfactant at CMC concentrations. |
Cecotti et al. 2018 [57] |