Enhancing biodegradation of vegetable oil-contaminated soil with soybean texturized waste, spent mushroom substrate, and stabilized poultry litter in microcosm systems.

Industrial activities contribute to environmental pollution, particularly through unregulated effluent discharges, causing adverse effects on ecosystems. Vegetable oils, as insoluble substances, exacerbate this pollution, forming impermeable films and affecting the oxygen transfer, leading to serious habitat disruption. Organic wastes, such as soybean texturized waste, spent mushroom substrate, and stabilized poultry litter, were assessed for their efficacy in enhancing the degradation of vegetable oil in contaminated soil. For this purpose, contaminated soil was amended with each of the wastes (10% w/w) using microcosm systems, which were monitored physico-chemically, microbiologically and toxicologically. Results indicate that the wastes promoted significant oil degradation, achieving 83.1, 90.7, and 86.2% removal for soybean texturized waste, spent mushroom substrate, and stabilized poultry litter, respectively, within a 90-day period. Additionally, they positively influenced soil microbial activity, as evidenced by increased levels of culturable microorganisms and hydrolytic microbial activity. While bioassays indicated no phytotoxicity in most cases, soybean texturized waste exhibited inhibitory effects on seed germination and root elongation of Lactuca sativa. This study significantly enhances our comprehension of remediation techniques for sites tainted with vegetable oils, highlighting the critical role of organic waste as eco-friendly agents in soil restoration. Emphasizing the practical implications of these findings is imperative to underscore the relevance and urgency of addressing vegetable oil contamination in soil. Moving forward, tailored strategies considering both contaminant characteristics and soil ecosystem traits are vital for ensuring effective and sustainable soil remediation.

Bioremediation of an industrial soil contaminated by hydrocarbons in microcosm system, involving bioprocesses utilizing co-products and agro-industrial wastes.

The present study describes practical implication of bioaugmentation and biostimulation processes for bioremediation of an industrial soil chronically contaminated by hydrocarbons. For this purpose, biomass production of six autochthonous hydrocarbon-degrading bacteria were evaluated as inoculum of bioaugmentation strategy, by testing carbon and nitrogen sources included co-products and agro-industrial waste as sustainable and low-cost components of the growth medium. Otherwise, biostimulation was approached by the addition of optimized concentration of nitrogen and phosphorus. Microcosm assays showed that total hydrocarbons (TH) were significantly removed from chronically contaminated soil undergoing bioremediation treatment. Systems Mix (bioaugmentation); N,P (biostimulation) and Mix + N,P (bioaugmentation and biostimulation) reached higher TH removal, being 89.85%, 91.00%, 93.04%, respectively, comparing to 77.83% of system C (natural attenuation) at 90 days. The increased heterotrophic aerobic bacteria and hydrocarbon degrading bacteria counts were according to TH biodegrading process during the experiments. Our results showed that biostimulation with nutrients represent a valuable alternative tool to treat a chronically hydrocarbon-contaminated industrial soil, while bioaugmentation with a consortium of hydrocarbon degrading bacteria would be justified when the soil has a low amount of endogenous degrading microorganisms. Furthermore, the production of inoculum for application in bioaugmentation using low-cost substrates, such as industrial waste, would lead to the development of an environmentally friendly and attractive process in terms of cost-benefit.

Optimization of biomass production by autochthonous Pseudomonas sp. MT1A3 as strategy to apply bioremediation in situ in a chronically hydrocarbon-contaminated soil.

These days, petroleum hydrocarbon pollution has become a global problem, because of this, bioremediation is presented as a strategy for cleaning up sites contaminated with organic pollutants, and it has an increasing role in relation to the potential it presents as a non-invasive and cost-effective technology. The aim of this study is to optimize the biomass production of Pseudomonas sp. MT1A3 strain as a soil bioremediation approach for petroleum hydrocarbon polluted environments. Factorial experimental designs were employed to study the effect of several factors of composition medium and incubation conditions on biomass production. Agro-industrial wastes such as peanut oil as carbon source, NaNO3 as nitrogen source and incubation temperature were found to be significant independent variables. These factors were further optimized using Box-Behnken design. Combination of peanut oil 18.69 g/L, NaNO3 2.39 g/L and 26.06 °C incubation temperature was optimum for maximum biomass production of MT1A3 and the model validated in a bioreactor allowed to obtain 9.67 g/L. Based on these results, this autochthonous strain was applied in bioaugmentation as a bioremediation strategy through microcosm designs, reaching 93.52% of total hydrocarbon removal at 60 days. This constitutes a promising alternative for hydrocarbon-contaminated soil. Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-022-03183-6.