Biostimulation potential of biochar for remediating the crude oil contaminated soil and plant growth

Abstract

Crude oil contamination is a serious environmental threat to soil and plants growing in it. Biochar has the potential of biostimulation for remediation of crude oil-contaminated soil. Therefore, the current research was designed to analyze the bio-stimulatory impact of biochar for remediating the crude oil contaminated soil (10%, and 15%), and growth of maize under glasshouse conditions. Biochar was produced by pyrolysis of Australian pines at 350 °C. Soil incubations were done for 20 days. The results of soil analysis showed that the crude oil degradation efficiency of biochar was 34%. The soil enzymatic activities had shown 38.5% increase in fluorescein diacetate (FDA) hydrolysis and 55.6% increase in dehydrogenase activity in soil incubated with biochar in comparison to control. The soil microbial diversity was improved to 41% in biochar treated soil with respect to untreated one, while microbial respiration rate had shown a 33.67% increase in soil incubated with biochar with respect to control under oil stress. Gas Chromatography Mass spectrometry (GC-MS) analysis had shown the high content of low molecular weight hydrocarbons (C 9 -C 13 ) in the soil incubated with biochar in comparison to untreated soil. Biochar showed a significant increase in fresh and dry biomass (25%, 14.61%), leaf area (10%), total chlorophyll (11%), water potential (21.6%), osmotic potential (21%), and membrane stability index (12.7%). Moreover, biochar treatment showed a higher increase in the contents of proline (29%), total amino acids (18%), soluble sugars (30.4%), and antioxidant enzymes like superoxide dismutase (16.5%), catalase (11%), and peroxidase (12%). Overall, the results of the present study suggest the bio-stimulating potential of biochar for degradation of hydrocarbons in crude oil contaminated soil and their growth-stimulating effects on maize.

Potential of biochar for hydrocarbon degradation of crude oil–contaminated soils

“…Its slow-release property might be the reason why plant growth was not noticed in the early weeks of planting. Saeed et al (2021) also observed an increase in fresh and dry biomass due to the incubation of biochar in crude oil-contaminated soils. Shahid et al (2017) reported an improvement in plant growth due to remediation.…”

“…This is in line with the works of Ibrahim et al (2016) who reported increased TPH remediation with an increase in rate of activated carbon. Previous studies have also demonstrated the bio-stimulating potential of biochar for degradation of hydrocarbons in crude oil contaminated soil (Qin et al, 2013;Saeed et al, 2021). Galitskaya et al (2016) also reported that the addition of biochar to oil-polluted soils that were mixed and moistened resulted in an increase in hydrocarbon degradation rates compared to when mixing and moistening was used alone.…”

“…The degradation efficiency of TPH was calculated using the following equation by Saeed et al. (2021): $$$$\begin{equation*}{\mathrm{Degradation\;efficiency\;}}\left( {\mathrm{\% }} \right) = \frac{{{\mathrm{TPH}}0 - {\mathrm{TPH}}60}}{{{\mathrm{TPH}}0}} \times 100{\mathrm{\% }}\end{equation*}$$$$where TPH 0 is the total petroleum hydrocarbon on day 0 and TPH 60 is the total petroleum hydrocarbon after 60 days of planting.…”

“…The degradation efficiency of TPH was calculated using the following equation by Saeed et al (2021):…”

Changes in the Enzymatic Activity of Oil-Contaminated Soils

“…При внесении грибов Fusarium equiseti и Cylindrocarpon magnusianum на 10% нефтезагрязненных почвах межфазная активность гриба Fusarium equiseti, в сочетании с фиторемедиатом и биопрепаратом, почти в 1,2 и 1,5 раза превышала вариант с применением гриба Cylindrocarpon magnusianum в полном комплексе мелиорантов [8]. По данным ученых, биоуголь, как потенциальный сорбент для удаления и разложения нефти в почвах, повысил скорость очистки на 52,2% и активность фермента каталазы в 1,8 раза по сравнению с контролем [9], биоуголь усиливает микробную и ферментативную активность почвы, активность по разложению углеводородов [10]. При непосредственном использовании ферментов природные ферменты микроорганизмов используются для разложения загрязнителей окружающей среды [11].…”