Bioaugmentation Techniques Research Articles

Remediation of petroleum-contaminated site soil by bioaugmentation with immobilized bacterial pellets stimulated by a controlled-release oxygen composite

Bioaugmentation techniques still show drawbacks in the cleanup of total petroleum hydrocarbons (TPHs) from petroleum-contaminated site soil. Herein, this study explored high-performance immobilized bacterial pellets (IBPs) embed Microbacterium oxydans with a high degrading capacity, and developed a controlled-release oxygen composite (CROC) that allows the efficient, long-term release of oxygen. Tests with four different microcosm incubations were performed to assess the effects of IBPs and CROC on the removal of TPHs from petroleum-contaminated site soil. The results showed that the addition of IBPs and/or CROC could significantly promote the remediation of TPHs in soil. A CROC only played a significant role in the degradation of TPHs in deep soil. The combined application of IBPs and CROC had the best effect on the remediation of deep soil, and the removal rate of TPHs reached 70%, which was much higher than that of nature attenuation (13.2%) and IBPs (43.0%) or CROC (31.9%) alone. In particular, the CROC could better promote the degradation of heavy distillate hydrocarbons (HFAs) in deep soil, and the degradation rates of HFAs increased from 6.6% to 33.2%–21.0% and 67.9%, respectively. In addition, the IBPs and CROC significantly enhanced the activity of dehydrogenase, catalase, and lipase in soil. Results of the enzyme activity were the same as that of TPH degradation. The combined application of IBPs and CROC not only increased the microbial abundance and diversity of soil, but also significantly enhanced the enrichment of potential TPH-biodegrading bacteria. M. oxydans was dominant in AP (bioaugmentation with addition of IBPs) and APO (bioaugmentation with the addition of IBPs and CROC) microcosms that added IBPs. Overall, the IBPs and CROC developed in this study provide a novel option for the combination of bioaugmentation and biostimulation for remediating organic pollutants in soil.

Biodegradation of bonny light crude oil by plasmid and non-plasmid borne soil bacterial strains using biostimulation and bioaugmentation techniques

A laboratory scale study was designed and conducted to assess the biodegradation of Bonny light crude oil by plasmid and non-plasmid borne soil bacterial strains using biostimulation and bioaugmentation techniques. The enrichment technique, turbidometric test, plasmid curing test, molecular identification method, biostimulation test, bioaugmentation test and gas chromatographic technique were carried out using standard analytical techniques. The physicochemical analysis result showed that the pH was slightly neutral, the organic carbon content was higher (2.32 to 4.34%), the conductivity was higher (0.41 to 0.44 μS/cm), and the water holding capacity was lower (0.27 percent and 10.11 kg, respectively). Based on their capacity to use crude oil, the results showed that 22 of the 60 isolated bacterial strains had higher pollutant degrading potentials (A600nm > 0.3).The identified potent hydrocarbon degraders includes: Bacillus spp., Pseudomonas aeruginosa KAVK01 and Ochrobacterium E85b strains. The highest degradation efficiency of 91% was found in soil that had been contaminated with 3 % (v/w) crude oil, amended with inorganic salts, and inoculated with plasmid-borne mixed cultures. The result further indicated that the consortium of plasmid borne isolates enhanced the reduction of the crude oil from the initial concentration of 10,318 ppm to 501 ppm (95 %) whereas 64 % decontamination was facilitated by the consortium of plasmid cured isolates. The information gathered from this investigation may be useful in choosing bacterial species, particularly plasmid-borne ones that can be employed to biodegrade soil contaminated by crude oil in Nigeria's Niger Delta region as well as the sample collection locations.

Research on current situation of farmland runoff pollution and ecological treatment technology

Farmland runoff pollution, caused by excessive use of fertilizers and pesticides, poses serious threats to water quality and aquatic ecosystems. To address this issue, various ecological treatment technologies have been developed and applied, such as vegetated ditches, constructed wetlands, and bioaugmentation techniques. These systems aim to reduce nutrient and pesticide concentrations in runoff water and enhance soil quality and biodiversity. This study reviews the current state of farmland runoff pollution and the existing ecological treatment methods. It also presents the results of our comparative analysis of the performance and efficiency of different treatment systems across multiple study sites with diverse climatic conditions. We demonstrate that ecological treatment technologies can effectively remove pollutants from runoff water and improve soil properties and microbial activity. We also discuss the implications and challenges of applying these technologies for agricultural sustainability and environmental protection.

Enhancing the Strength of Mine Residue Soil by Bioremediation Combined with Biopolymers

Traditional soil stabilization methods are usually associated with high energy consumption, carbon emissions, and long-term environmental impact. Recent developments have shown the potential use of bio-based techniques as eco-friendly alternatives for soil stabilization. The present work studies the effects of the addition of the biopolymers xanthan gum (XG) or carboxymethyl cellulose (CMC) to a mine residue soil, combined or not with biostimulation and bioaugmentation techniques, in terms of compressive stress–strain behavior. Unconfined compressive strength (UCS) tests were performed on previously disturbed samples (two cycles of percolation, extraction and homogenization) to evaluate if the biostimulation and bioremediation remain active in a real adverse scenario. The results allowed for us to conclude that both biopolymers, when applied individually (with a content of 1%), are effective stabilizers (CMC allows for unconfined compressive strength increases of up to 109%), showing better results for CMC than Portland cement. The biostimulation of the autochthonous community of the mine residue soil was revealed to be a non-effective technique, even when combined with the biopolymers. However, good results were observed when the bioaugmentation was combined with xanthan gum, with unconfined compressive strength improvements of up to 27%. The study revealed that these bio-based techniques are promising soil engineering techniques, offering environmentally friendly alternatives for sustainable soil stabilization and contributing to a greener and more sustainable future.

Advancements in algal membrane bioreactors: Overcoming obstacles and harnessing potential for eliminating hazardous pollutants from wastewater

This paper offers a comprehensive analysis of algal-based membrane bioreactors (AMBRs) and their potential for removing hazardous and toxic contaminants from wastewater. Through an identification of contaminant types and sources, as well as an explanation of AMBR operating principles, this study sheds light on the promising capabilities of AMBRs in eliminating pollutants like nitrogen, phosphorus, and organic matter, while generating valuable biomass and energy. However, challenges and limitations, such as the need for process optimization and the risk of algal-bacterial imbalance, have been identified. To overcome these obstacles, strategies like mixed cultures and bioaugmentation techniques have been proposed. Furthermore, this study explores the wider applications of AMBRs beyond wastewater treatment, including the production of value-added products and the removal of emerging contaminants. The findings underscore the significance of factors such as appropriate algal-bacterial consortia selection, hydraulic and organic loading rate optimization, and environmental factor control for the success of AMBRs. A comprehensive understanding of these challenges and opportunities can pave the way for more efficient and effective wastewater treatment processes, which are crucial for safeguarding public health and the environment.

Oil biodegradation studies with an immobilized bacterial consortium in plant biomass for the construction of bench-scale bioreactor

Increasing exploration of natural sources and the development of new oil-derived technologies have caused environmental contamination. Thus, among the bioremediation strategies, biostimulation and bioaugmentation techniques have been the most used in the current literature. This study aimed to build a bench-scale bioreactor to promote degradation used ship engine lubricating oil using an immobilized bacterial consortium in Salvinia sp. (SS). For this purpose, bacterial strains were isolated from the hydrocarbon-contaminated moist soil in the marginal at Guanabara Bay, Rio de Janeiro, Brazil, followed by isolation, identification of microorganisms, and biodegradation tests. Then these microorganisms were immobilized in SS biomass. The bacterial consortium underwent biodegradation tests and bioreactor biodegradation on a bench scale. According to the results, the consortium of Bacteria like Bacillus could biodegrade 52.9% of the lubricating oil and 0.027 d − 1 degradation rate.

Coupling and environmental implications of in situ formed biogenic Fe–Mn minerals induced by indigenous bacteria and oxygen perturbations for As(III) immobilization in groundwater

Iron (Fe)–manganese (Mn) minerals formed in situ can be used for the natural remediation of the primary poor-quality groundwater with coexistence of arsenite [As(III)], Mn(II), and Fe(II) (PGAMF). However, the underlying mechanisms of immobilization and coupling of As, Mn, and Fe during in-situ formation of Fe–Mn minerals in PGAMF remains unclear. The simultaneous immobilization and coupling of arsenic (As), Mn, and Fe in PGAMF during in-situ formation of biogenic Fe–Mn minerals induced by O2 perturbations and indigenous bacteria (Comamonas sp. RM6) were investigated at the different molar ratios of Fe(II):Mn(II) (1:1, 2:1, and 3:1). Compared with systems without Fe(II) in the presence of Mn(II), the coexisted Fe(II) significantly enhanced Mn(II) bio-oxidation and mineral precipitation, resulting in As immobilization increased by 5, 7, and 7 times at initial Fe(II) concentration of 0.3, 0.6, and 0.9 mM, respectively. Moreover, the As(III) immobilization efficiencies in Mn(II) and Fe(II) mixed system at initial Fe(II) concentration of 0.3, 0.6, and 0.9 mM were 73%, 91%, and 92%, respectively, that were significantly higher than those of single Fe(II) system (30%, 59%, and 74%) and those of single Mn(II) system (12%), indicating that Fe(II) and Mn(II) oxidation synergically enhanced As(III) immobilization. This was mainly attributed to the formation and As adsorption capacity of biogenic Fe–Mn minerals (BFMM). The formed BFMM significantly facilitated simultaneous immobilization of Fe, Mn, and As in PGAMF by oxidation, adsorption, and precipitation/coprecipitation, a coupling of biological, physical, and chemical processes. Fe component was mainly responsible for As fixation, and Mn component dominated As(III) oxidation. Based on the results from this work, biostimulation and bioaugmentation techniques can be developed for in-situ purification and remediation of PGAMF. This work provides insights into the simultaneous immobilization of pollutants in PGAMF, as well as promising strategies for in-situ purification and remediation of PGAMF.

Enhanced biodegradation of hexachlorocyclohexane (HCH) isomers by Sphingobium sp. strain D4 in the presence of root exudates or in co-culture with HCH-mobilizing strains

Lindane and other 1,2,3,4,5,6-hexachlorocyclohexane (HCH) isomers are persistent organic pollutants highly hydrophobic, which hampers their availability and biodegradation. This work aimed at (i) investigating genes encoding enzymes involved in HCH degradation in the bacterium Sphingobium sp. D4, (ii) selecting strains, from a collection of environmental isolates, able to mobilize HCHs from contaminated soil, and (iii) analysing the biodegradation of HCHs by strain D4 in co-culture with HCH-mobilizing strains or when cultivated with root exudates. Fragments of the same size and similar sequence to linA and linB genes were successfully amplified. Two isolates, Streptomyces sp. M7 and Rhodococcus erythropolis ET54b able to produce emulsifiers and to mobilize HCH isomers from soil were selected. Biodegradation of HCH isomers by strain D4 was enhanced when co-inoculated with HCH mobilizing strains or when cultivated with root exudates. The degrader strain D4 was able to decompose very efficiently HCHs isomers, reducing their concentration in soil slurries by more than 95% (from an average initial amount of 50 ± 8 mg HCH kg−1 soil) in 9 days. The combination of HCH-degrading and HCH-mobilizing strains can be considered a promising inoculum for future soil bioremediation studies using bioaugmentation techniques or in combination with plants in rhizodegradation assays.

Membrane composition and successful bioaugmentation. Studies of the interactions of model thylakoid and plasma cyanobacterial and bacterial membranes with fungal membrane-lytic enzyme Lecitase ultra

Cyanobacterial/bacterial consortia are frequently inoculated to soils to increase the soil fertility and to accelerate the biodegradation of organic pollutants. Moreover, such consortia can also be successfully applied in landfills especially for the biodegradation of plastic wastes. However, the bioaugmentation techniques turn out frequently inefficient due to the competition of the indigenous microorganisms attacking directly these inoculated or secreting to their surroundings cell wall and membrane-lytic enzymes. It can be hypothesized that the resistance of the microbial membrane to the enzymatic degradation is correlated with its lipid composition. To verify this hypothesis glycolipid and phospholipid Langmuir monolayers were applied as models of thylakoid and plasma cyanobacterial and bacterial membranes. Hybrid fungal enzyme Lecitase ultra joining the activity of lipase and phospholipase A1 was applied as the model of fungal membrane-lytic enzyme. It turned out that anionic thylakoid lipids sulfoquinovosyldiacylglycerol and phosphatidylglycerols were the main targets of Lecitase ultra in the model multicomponent thylakoid membranes. The resistance of the model plasma bacterial membranes to enzymatic degradation depended significantly to their composition. The resistance increased generally when the unsaturated lipids were exchanged to their saturated counterparts. However, most resistant turned out the membranes composed of unsaturated phosphatidylamine and saturated anionic phospholipids.

Effectiveness of biochar application and bioaugmentation techniques for the remediation of freshly and aged diesel-polluted soils

In order to contribute to a minimum impact on soil biocenosis during the application of in-situ bioremediation techniques, this work assessed the efficiency of a scarcely used combination of biochar and a bioaugmentation based on an autochthonous bacterial consortium. Bioaugmentation-biochar combination was assessed by using soil samples from a polluted site with two pollution scenarios: a) soil with aged diesel, and b) clean soil to which fresh diesel was later added simulating a recent pollution event. The autochthonous consortium, isolated from the aged-diesel soil, was genetically, taxonomically and functionally characterized by these authors in a previous work. The biochar used was obtained from tree pruning residues. In both scenarios, four treatments were carried out under short-term test conditions: i) natural attenuation, ii) biochar, iii) bioaugmentation, and iv) biochar-bioaugmentation combination. Our results show that the bioaugmentation-biochar combination was significantly more effective than the simple treatments. This combination produced more than 20% diesel degradation in both scenarios over twelve weeks. Simultaneously, an increase in bacterial diversity was observed in that period. Therefore, using biochar combined with bioaugmentation suggests synergies that lead to a highly efficient and environmentally friendly bioremediation processes.

The potential association of Echinochloa polystachya (Kunth) Hitchc. with bacterial consortium for petroleum degradation in contaminated soil

In recent years, environmental impacts related to the contamination of ecosystems by petroleum have become frequent. In contact with the environment, petroleum can cause toxic effects in the biodiversity and on human health and compromise both water and land resources. Among the strategies to overcome this issue, bioremediation stands out as viable and promising alternative for environmental decontamination. To bioremediate petroleum-contaminated sites, phytoremediation and bioaugmentation techniques can be used. Thus, this research aimed to evaluate through a pot experiment four bioremediation strategies: (1) natural attenuation, (2) phytoremediation with Echinochloa polystachya, (3) bioaugmentation with bacterial consortium and (4) bioaugmentation-assisted phytoremediation, for the treatment of a co-contaminated soil presenting 100 g kg−1 of petroleum. In addition, two control treatments were carried out with substrates not contaminated with petroleum: (5) control with E. polystachya and (6) control treatment with bacterial consortium and E. polystachya. The experiment lasted 60 days in a greenhouse. The survival rate of E. polystachya was 100% in the contaminant tolerance aspect, resulting in increased stomatal density and aerenchyma, affecting few parameters of the plant, which demonstrate its phytoremediation capacity. In all treatments, petroleum degradation occurred. The highest degree of total petroleum hydrocarbon removal was obtained for contaminated soil cultivated with E. polystachya (phytoremediation), followed by contaminated soil cultivated with E. polystachya and bacterial (bioaugmentation-assisted phytoremediation treatment) and contaminated soil treated with bacterial consortium (bioaugmentation). Natural attenuation was less effective, proving the efficiency of the phytoremediation by E. polystachya and bacterial consortium, that responded positively to the stresses generated by contamination. However, further studies should direct to aim understanding the metabolic processes involved in the degradation and that these approaches to assist in environmental decontamination.

Isolation and Characterization in a Soil Conditioned With Foaming Agents of a Bacterial Consortium Able to Degrade Sodium Lauryl Ether Sulfate.

The anionic surfactant Sodium Lauryl Ether Sulfate (SLES) is the principal component of several commercial foaming products for soil conditioning in the tunneling industry. Huge amounts of spoil material are produced during the excavation process and the presence of SLES can affect its re-use as a by-product. Anionic surfactants can be a risk for ecosystems if occurring in the environment at toxic concentrations. SLES biodegradability is a key issue if the excavated soil is to be reused. The aim of this study was to identify bacteria able to degrade SLES, so that it could potentially be used in bioaugmentation techniques. Enrichment cultures were performed using bacterial populations from spoil material collected in a tunnel construction site as the inoculum. A bacterial consortium able to grow in a few hours with SLES concentrations from 125 mg/L to 2 g/L was selected and then identified by Next Generation Sequencing analysis. Most of bacteria identified belonged to Gamma-Proteobacteria (99%) and Pseudomonas (ca 90%) was the predominant genus. The bacterial consortium was able to degrade 94% of an initial SLES concentration of 250 mg/L in 9 h. A predictive functional analysis using the PICRUSt2 software showed the presence of esterase enzymes, responsible for SLES degradation. The bacterial consortium selected could be useful for its possible seeding (bioaugmentation) on spoil material from tunneling excavation.

Paraquat Degradation From Contaminated Environments: Current Achievements and Perspectives.

Paraquat herbicide has served over five decades to control annual and perennial weeds. Despite agricultural benefits, its toxicity to terrestrial and aquatic environments raises serious concerns. Paraquat cannot rapidly degrade in the environment and is adsorbed in clay lattices that require urgent environmental remediation. Advanced oxidation processes (AOPs) and bioaugmentation techniques have been developed for this purpose. Among various techniques, bioremediation is a cost-effective and eco-friendly approach for pesticide-polluted soils. Though several paraquat-degrading microorganisms have been isolated and characterized, studies about degradation pathways, related functional enzymes and genes are indispensable. This review encircles paraquat removal from contaminated environments through adsorption, photocatalyst degradation, AOPs and microbial degradation. To provide in-depth knowledge, the potential role of paraquat degrading microorganisms in contaminated environments is described as well.

Potential of bacteria isolated from diesel-contaminated seawater in diesel biodegradation

Abstract The purpose of this study was to analyze the potential of bacteria isolated from diesel-contaminated seawater for diesel biodegradation. Samples of diesel-contaminated seawater were collected from a ship dismantling facility in Madura Island, Indonesia. Bacteria were isolated using the serial dilution method. Bacteria with potential for diesel degradation were screened using nutrient agar and mineral salt medium (MSM) with 0%, 5%, 10%, and 15% (v/v) diesel as carbon source. Diesel degradation test was performed by inoculating potential bacterium into MSM with the optimum concentration selected from the screening stage. Diesel degradation percentage was analyzed by gas chromatography–mass spectrometry (GC–MS). In this research, six bacterial species were isolated and used in the screening stage. The optimum concentration was 10% diesel (v/v) based on the screening stage, and the bacteria coded as MFI5 exhibited the highest growth with 8.13 ± 0.19 log colony forming unit/mL after 7 days of incubation. The bacteria coded as MFI5 was identified as Vibrio alginolyticus. Results showed that V. alginolyticus was able to degrade diesel up to 26.78% after 14 days of incubation at 10% initial diesel concentration (v/v). V. alginolyticus can potentially degrade diesel in a contaminated environment with further investigation using the biostimulation and bioaugmentation techniques.

Exploitation of novel synthetic bacterial consortia for biodegradation of oily-sludge TPH of Iran gas and oil refineries

The main aim of this study is to examine the effects of exploitation of synthetic combination of indigenous and exogenous bacteria on biodegradation of South Pars gas refineries’ (SPGRs) oily sludge contaminants in liquid and soil media during a 60-day time period. To the best of authors’ knowledge, this is the first time that the capabilities of Staphylococcus spp., Lysinibacillus fusiformis, and Citrobacter amalonaticus for degradation of petroleum compounds are uncovered. One of the most important achievements of the combined consortium, is the additional reduction of the broth surface tension due to biosurfactants production. Results show that the combined consortium has the highest biodegradation ability in 1% (w/v) oily sludge supplied mineral salt and soil media by respectively 81.0% and 71.2% through biostimulation+bioaugmentation techniques. It is also observed that adding exogenous bacteria to indigenous ones contributes to increase of oily-sludge degradation by 11.4% in liquid media and 17.6% in soil. Finally, addition of exogenous bacteria resulted in significant increase of removal percentage of alkanes, aromatics, and asphalthene+resins contaminants in liquid and soil media.

Enhancement of Profenofos Remediation Using Stimulated Bioaugmentation Technique

AbstractProfenofos, an organophosphorus pesticide, has been reported its contamination in groundwater. The current study emphasized on the use of integrated bioaugmentation and biostimulation techniques to enhance profenofos bioremediation. A profenofos-degrading consortium including

The application of biotechnology on the enhancing of biogas production from lignocellulosic waste.

Anaerobic digestion of lignocellulosic waste is considered to be an efficient way to answer present-day energy crisis and environmental challenges. However, the recalcitrance of lignocellulosic material forms a major obstacle for obtaining maximum biogas production. The use of biological pretreatment and bioaugmentation for enhancing the performance of anaerobic digestion is quite recent and still needs to be investigated. This paper reviews the status and perspectives of recent studies on biotechnology concept and investigates its possible use for enhancing biogas production from lignocellulosic waste with main emphases on biological pretreatment and bioaugmentation techniques.

Reduced leaching of the herbicide MCPA after bioaugmentation with a formulated and stored Sphingobium sp.

The use of pesticides on sandy soils and on many non-agricultural areas entails a potentially high risk of water contamination. This study examined leaching of the herbicide 4-chloro-2-methylphenoxyacetic acid (MCPA) after bioaugmentation in sand with differently formulated and stored Sphingobium sp. T51 and at different soil moisture contents. Dry formulations of Sphingobium sp. T51 were achieved by either freeze drying or fluidised bed drying, with high initial cell viability of 67-85%. Storage stability of T51 cells was related to formulation excipient/carrier and storage conditions. Bacterial viability in the fluidised bed-dried formulations stored at 25°C under non-vacuum conditions was poor, with losses of at least 97% within a month. The freeze-dried formulations could be stored substantially longer, with cell survival rates of 50%, after 6months of storage at the same temperature under partial vacuum. Formulated and long-term stored Sphingobium cells maintained their MCPA degradation efficacy and reduced MCPA leaching as efficiently as freshly cultivated cells, by at least 73% when equal amounts of viable cells were used. The importance of soil moisture for practical field bioaugmentation techniques is discussed.

Recent studies on thermophilic anaerobic bioconversion of lignocellulosic biomass

This paper reviews recent research developments in biological thermophilic lignocellulosic biomass conversion based on sixty four references published in the past 4 years (2009–2012). Bioconversion of hydrolysate and lignocellulosic biomass with or without pretreatment under thermophilic conditions (with temperatures higher than 50 °C) to fermentation products like hydrogen, methane, ethanol and carboxylic acids is discussed in terms of the bioaugmentation techniques and microorganisms involved. The discussion was divided into two branches according to the form of substrate applied: one branch targeted the fermentation of liquid hydrolysate (liquid fraction generated from the pretreatment of lignocellulosic biomass); the other one summarized the studies using raw or pretreated solid lignocellulosic biomass as a feedstock. Fermentation of the hydrolysate was discussed from the aspects of hydrolysate toxicity tolerance and hydrolysate detoxification techniques, while, process affecting parameters like pH, enrichment processes, substrate type and loading as well as microbial communities were reviewed for solid lignocellulosic biomass fermentation. Key information was compiled into four tables respectively summarizing the optimal fermentation conditions for the production of hydrogen/methane and ethanol/carboxylic acids from hydrolysate and lignocellulosic biomass. Information delivered in this article may shed light on the perspectives of the scientific and technical challenges faced by thermophilic anaerobic lignocellulose bioconversion.

Comparison of biostimulation and bioaugmentation techniques for the remediation of used motor oil contaminated soil

This study was carried out on the bioremediation of used motor oil contaminated soil artificially contaminated to a pollutant level of 40,000ppm using biostimulation and bioaugmentation remediation techniques for 42 days. Four treatment options were investigated in wooden microcosms: Control (T1), water amended (T2), biostimulation (T3) and hybrid of biostimulation and bioaugmentation (T4). The effectiveness of bioremediation processes were monitored using the total petroleum hydrocarbon removal (TPH) and total bacterial count (TBC). T3 had the highest TPH removal rate (69.2±0.05%), followed by T4 (65.2±0.25%) and T2 (58.4±0.5%); the control (T1) had the lowest TPH removal rate (43.2±1.5%). TBC revealed that bioremediation actually took place; T4 had the highest maximum bacterial growth of 9.6E+07CFU/g, followed by T3 (7.2E+07CFU/g), T2 (1.7E+05CFU/g) and T1 (1.65E+05CFU/g). In addition, T3 had the highest metal removal rate (2.172%) and T4 had the lowest metal removal rate (0.203%).