Indigenous Consortium Research Articles

Bioremediation of uranium-contaminated groundwater with an indigenous consortium under high-nitrate conditions

Bioremediation of uranium-contaminated groundwater with an indigenous consortium under high-nitrate conditions

Enhanced indigenous consortia for the remediation of uranium-contaminated groundwater by bioaugmentation: Reducing and phosphate-solubilizing consortia

To investigate the strengthening effects and mechanisms of bioaugmentation on the microbial remediation of uranium-contaminated groundwater via bioreduction coupled to biomineralization, two exogenous microbial consortia with reducing and phosphate-solubilizing functions were screened and added to uranium-contaminated groundwater as the experimental groups (group B, reducing consortium added; group C, phosphate-solubilizing consortium added). β-glycerophosphate (GP) was selected to stimulate the microbial community as the sole electron donor and phosphorus source. The results showed that bioaugmentation accelerated the consumption of GP and the proliferation of key functional microbes in groups B and C. In group B, Dysgonomonas, Clostridium_sensu_stricto_11 and Clostridium_sensu_stricto_13 were the main reducing bacteria, and Paenibacillus was the main phosphate-solubilizing bacteria. In group C, the microorganisms that solubilized phosphate were mainly unclassified_f_Enterobacteriaceae. Additionally, bioaugmentation promoted the formation of unattached precipitates and alleviated the inhibitory effect of cell surface precipitation on microbial metabolism. As a result, the formation rate of U-phosphate precipitates and the removal rates of aqueous U(VI) in both groups B and C were elevated significantly after bioaugmentation. The U(VI) removal rate was poor in the control group (group A, with only an indigenous consortium). Propionispora, Sporomusa and Clostridium_sensu_stricto_11 may have played an important role in the removal of uranium in group A. Furthermore, the addition of a reducing consortium promoted the reduction of U(VI) to U(IV), and immobilized uranium existed in the form of U(IV)-phosphate and U(VI)-phosphate precipitates in group B. In contrast, U was present mainly as U(VI)-phosphate precipitates in groups A and C. Overall, bioaugmentation with an exogenous consortium resulted in the rapid removal of uranium from groundwater and the formation of U-phosphate minerals and served as an effective strategy for improving the treatment of uranium-contaminated groundwater in situ.

Ibuprofen-enhanced biodegradation in solution and sewage sludge by a mineralizing microbial consortium. Shift in associated bacterial communities

Ibuprofen (IBP) is a widely used drug of environmental concern as emerging contaminant due to its low elimination rates by wastewater treatment plants (WWTPs), leading to the contamination of the environment, where IBP is introduced mainly from wastewater discharge and sewage sludge used as fertilizer. This study describes the application of a consortium from sewage sludge and acclimated with ibuprofen (consortium C7) to accelerate its biodegradation both in solution and sewage sludge. 500 mg L-1 IBP was degraded in solution in 28 h, and 66% mineralized in 3 days. IBP adsorbed in sewage sludge (10 mg kg-1) was removed after bioaugmentation with C7 up to 90% in 16 days, with a 5-fold increase in degradation rate. This is the first time that bioaugmentation with bacterial consortia or isolated bacterial strains have been used for IBP degradation in sewage sludge. The bacterial community of consortium C7 was significantly enriched in Sphingomonas wittichii, Bordetella petrii, Pseudomonas stutzeri and Bosea genosp. after IBP degradation, with a special increase in abundance of S. wittichii, probably the main potential bacterial specie responsible for IBP mineralization. Thirteen bacterial strains were isolated from C7 consortium. All of them degraded IBP in presence of glucose, especially Labrys neptuniae. Eight of these bacterial strains (B. tritici, L. neptuniae, S. zoogloeoides, B. petrii, A. denitrificans, S. acidaminiphila, P. nitroreducens, C. flaccumfaciens) had not been previously described as IBP-degraders. The bacterial community that makes up the indigenous consortium C7 appears to have a highly efficient biotic degradation potential to facilitate bioremediation of ibuprofen in contaminated effluents as well as in sewage sludge generated in WWTPs.

A meta-omics approach to explore the biofuel-producing enzyme potential from extreme environmental conditions

Geothermally warmed spring water contaminated with decomposed leaf biomass are unique hot spring ecosystems , are expected to support the recycling of various nutrients and to host lignocellulose degrading thermostable enzymes, genes and bacteria. An attempt is made in the present study to explore CAZymes in a carbohydrate-contaminated unique environment at Deulajhari spring through a multi-omics approach using an indigenous consortium developed from the spring sediment. Co-assembly of shotgun metagenome and metatranscriptome libraries from the Deulajhari hot spring consortia sample recovered seventeen refined, high-quality near-complete genomes. The predominant recovery of thermophilic aerobic chemo-heterotrophic Meiothermus and Rhodothermus has been observed through genome reconstruction. The reported production of an array of enzymes, including xylanase, β-xylosidase, endoglucanase and polysaccharide deacetylase, establishes their lignocellulose-degrading ability. The unexpected strong positive correlation between predominating Meiothermus and less prevailing members of Acetobacteraceae, unclassified Gaiellaceae, unclassified Burkholderiaceae and Tepidimonas of the consortium signifies their unexplored role in biomass degradation. Furthermore, the synergistic involvement of the diverse enzymes represented by a vast gene repertoire is responsible for the degradation of complex plant polysaccharides by the group of bacteria. The novelty of the present study stems from the identification of a diverse range of potential lignocellulose-digesting enzymes expressed by the bacterial consortium. This finding emphasizes the significant potential of these enzymes in facilitating industrial-scale production of biofuel, making it a notable contribution to the field.

Microbial Consortium for Polycyclic Aromatic Hydrocarbons Degradation from Petroleum Hydrocarbon Polluted Soils in Rivers State, Nigeria

The study investigated the distribution of polycyclic aromatic hydrocarbon (PAH) degraders across two different petroleum hydrocarbon-polluted sites in the Niger Delta, Nigeria, and the ability of the reconstituted indigenous consortium to utilize these PAHs. Microorganisms were isolated after sample enrichment in naphthalene and anthracene, and biosurfactant production was measured using the emulsification index technique. PAH concentrations of approximately 6000 mg/kg and 9000 mg/kg in Tombia and Bodo were higher than the Department of Petroleum Resources (DPR) intervention limit of 40 mg/kg. The pH, soil texture and high conductivity affected microbial distribution significantly. A total of 12 bacteria from the genera Bacillus, Pseudomonas, Micrococcus and 3 fungal isolates (Fusarium, Aspergillus and Penicillium) from the 2 sites were able to utilize naphthalene and/or anthracene as sole carbon source. While the Tombia site had more microorganisms capable of PAH degradation with the redox indicator 2, 6-dichlorophenol indophenol (DCPIP) (10 bacterial and 3 fungal species), two bacterial species from Bodo were able to produce biosurfactant. The findings of this study indicate that indigenous microbes in the polluted sites are catabolically active and could be further stimulated for an effective eco-friendly and green removal of PAHs from oil-polluted soils while combined.

Can an indigenous consortium of arbuscular mycorrhizae effectively mitigate drought stress in argan trees (Argania spinosa L. Skeels) by modulating mineral nutrition and phosphatase activities?

Can an indigenous consortium of arbuscular mycorrhizae effectively mitigate drought stress in argan trees (Argania spinosa L. Skeels) by modulating mineral nutrition and phosphatase activities?

Metagenomic insight on consortium degradation of soil weathered petroleum and its supplement based on gene abundance change

Petroleum biodegradation is of importance for the mitigation of secondary pollutants from soil chemical remediation. Describing the gene abundance change of the petroleum degradation emerged as an important practice for success. In this study, an indigenous consortium with targeting-enzyme was utilized to develop a degradative system that was later subjected to metagenomic analysis on the soil microbial community. Centering on ko00625 pathway, abundance change of dehydrogenase gene was firstly found increasing from groups D, DS to DC in turn, just in an opposite direction with that of oxygenase. In addition, gene abundance of responsive mechanism went rising with degradative process as well. This finding sufficiently promoted that equal attention should be paid to both degradative and responsive processes. Hydrogen donor system was innovatively built on the consortium-used soil to satisfy the demand of dehydrogenase gene tendency and to sustain further petroleum degradation. Anaerobic pine-needle soil was supplemented to this system, bi-functionally serving as dehydrogenase substrate with nutrients and hydrogen donor. In doing so, two successive degradations optimally achieved the total removal rate 75.6–78.7% for petroleum hydrocarbon. The conception on the gene abundance changes and its corresponding supplement helps industries of concern to develop geno-tag guided framework.

Harnessing bacterial strain from rhizosphere to develop indigenous PGPR consortium for enhancing lobia (Vigna unguiculata) production

The rhizosphere microbes play a key role in plant nutrition and health. However, the interaction of beneficial microbes and Vigna unguiculata (lobia) production remains poorly understood. Thus, we aimed to isolate and characterize the soil microbes from the rhizosphere and develop novel microbial consortia for enhancing lobia production. Fifty bacterial strains were isolated from the rhizosphere soil samples of lobia. Finally, five effective strains (e.g., Pseudomonas sp. IESDJP-V1 and Pseudomonas sp. IESDJP-V2, Serratia marcescens IESDJP-V3, Bacillus cereus IESDJP-V4, Ochrobactrum sp. IESDJP-V5) were identified and molecularly characterized by 16 S rDNA gene amplification. All selected strains showed positive plant growth promoting (PGP) properties in broth culture. Based on morphological, biochemical, and plant growth promoting activities, five effective isolated strains and two collected strains (Azospirillum brasilense MTCC-4037 and Paenibacillus polymyxa BHUPSB17) were selected. The pot trials were conducted with seed inoculations of lobia (Vigna unguiculata) var. Kashi Kanchan with thirty treatments and three replications. The treatment combination T3 (Pseudomonas sp. IESDJP-V2), T14 (Pseudomonas sp. IESDJP-V2 + A. brasilense), T26 (Pseudomonas sp. IESDJP-V1+ B. cereus IESDJP-V4 + P. polymyxa) and T27 (IESDJP-V1+ IESDJP-V5+ A. brasilense) were recorded for enhancing plant growth attributes, yield, nutritional content like protein, total sugar, flavonoid and soil properties as compared to control and others. The effective treatments T3 (Pseudomonas sp.), T14 (Pseudomonas sp. IESDJP-V2 + A. brasilense), T26 (Pseudomonas sp. IESDJP-V1+ B. cereus IESDJP-V4 + P. polymyxa) and T27 (IESDJP-V1+ IESDJP-V5+ A. brasilense) recorded as potential PGPR consortium for lobia production. The treatment of single (Pseudomonas sp.), duel (IESDJP-V2 + A. brasilense) and triple combination (IESDJP-V1+ IESDJP-V4 + P. polymyxa) and (IESDJP-V1+ IESDJP-V5+ A. brasilense) can be further used for developing effective indigenous consortium for lobia production under sustainable farming practices. These PGPR bio-inoculant will be cost-effective, environment-friendly and socially acceptable.

Arbuscular mycorrhizal fungi enhanced the growth, phosphorus uptake and Pht expression of olive (Olea europaea L.) plantlets.

Olive (Olea europaea L.) is a highly mycotrophic species that has been introduced and cultivated in China for half a century. The arbuscular mycorrhizal fungi (AMF) is extremely valuable as a kind of biofertilizer to promote the health and vigor of olive plants. However, it is still unclear how native AMF impact growth and mineral nutrients, especially phosphorus absorption in the area where olive trees were introduced in China. In the present study, through a pot experiment, the effects of native AMF on the growth, phosphorus uptake and expression levels of four phosphate transporter genes (Pht) of olive plantlets were characterized. We found that (1) typical AMF colonization was observed within the roots of inoculated olive plantlets, and the growth of plantlets was significantly promoted; (2) some indigenous consortia (AMF1 and AMF2) notably promoted the absorption of phosphorus, fertilizers significantly increased the foliar content of nitrogen, and both AMF inoculation and fertilization had no significant effect on the uptake of potassium; and (3) AMF inoculation enhanced the expression of phosphate transporter genes in inoculated olive roots. This work demonstrates the effectiveness of native AMF on the cultivation of robust olive plantlets and highlights the role of AMF in increasing phosphorus uptake. There is great potential in using native AMF consortia as inoculants for the production of healthy and robust olive plantlets.

Consortium of Indigenous Fecal Bacteria in the Treatment of Metabolic Syndrome.

The features of gut microbiota in metabolic syndrome (MS) and ways to correct it using autoprobiotics, based on indigenous bacteria obtained from fecal samples of the host, remain unexplored. The aim of the study was to investigate the effectiveness of an indigenous consortium (IC) of fecal bacteria in treatment of patients with MS. The study was carried out on 36 patients with MS, manifested with abdominal obesity, eating disorders, dyslipidemia, and hypertension. The control group was formed by 20 healthy volunteers. Samples of IC and gut microbiota content were examined by qPCR and metagenome (16S rRNA) analysis before and after therapy. The decrease in anthropometric parameters of obesity, liver enzyme level correction, reduction in C reactive protein and triglyceride concentrations were revealed after IC usage. The decrease in genera Bifidobacterium, Enterobacter, Paraprevotella, and Prevotella, as well as an increase in Bacteroides fragilis and Oscillospira spp. populations were shown after consumption of IC. A negative correlation between the quantity of B. fragilis and the anthropometric parameters of obesity (r = −0.48) and C reactive protein level (r = −0.36) in serum was established. Thus, IC can be considered as a potential functional personified product for the therapy of MS.

Characterization of the indigenous fermenters for the production of fermented condiments from soybean seeds

Several studies have shown that most condiments consumed in Nigeria today are produced from allochtonous microorganisms, and these organisms are usually associated with diseases or create negative impacts into the condiments. Several attempts have been made in order to control this ugly situation but there is still controversial thought in the choice of microorganism to be used in order to produce a non-toxic and palatable condiment. The aim of this study was to isolate and characterize the indigenous fermenters for the production of fermented condiments from soybean seeds. Soybean (Glycine max) sample were gotten from the market and were transferred aseptically to the laboratory for further analysis, the samples were prepared and fermented in a wrapped Thaumatococcus danielli leaves (called Uma in Igbo and Ewe eran in Yoruba). The specific microbial genera were enumerated on appropriate selected media and identified using standard identification parameters with the aid of identification and taxonomic manuals. Soybean sample was fermented with indigenous microorganisms isolated from 7 days old fermented soybean sample. This was oven-dried, pulverized and packaged in a cleaned sterile screw capped container. Lactobacillus plantarum strain ZS 2058 (L), Bacillus subtilis strain 168 (B) and Saccharomyces cerevisiae strain YJM555 (Y) were the indigenous microbes isolated from the 7 days locally fermented soybean and these were used for the production of light to dark brown condiments with water activity ranging from 0.27 – 0.37 for the fermented soybean in the plate and 0.22 - 0.36 for the fermented soybean wrapped with Thaumatococcus danielli leaves (called “uma” in Igbo and “ewe eran” in Yoruba). It was observed that the condiments produced using indigenous consortium of BLY was significantly (p<0.05) more preferable to the ones produced from single strain. Therefore this study has shown indigenous B, L, Y, BL and BLY produced good and palatable condiments from fermented soybean.

Retrieving sulfur in thiosulfate bio-oxidation: indigenous consortium vs. its dominant isolate Ochrobactrum sp.

Sulfur compounds such as thiosulfate are among contaminants with undesirable effects on ecosystems. Sulfur-oxidizing bacteria (SOB) can metabolize these compounds into less pernicious products such as elemental sulfur (S0). In this study, products distribution of thiosulfate bio-oxidation with emphasis on S0 was investigated in shake flasks (SFs) and 1 L stirred bioreactor (SB) using an indigenous SOB consortium. Enrichment of original cells taken from Atashkoh soil resulted in complete oxidation of 3000 ppm thiosulfate and 14% S0 formation as compared to 45% oxidation of original cells. The agarose plate method was selected to preserve this enriched-consortium due to the retrieval of more sulfur (30% in SF). Oxidation of 3000 ppm thiosulfate in SB resulted in 35.2% S0 formation and noticeably a higher thiosulfate depletion rate of 1 compared to 0.2 mmol S L−1 h−1 in SF. Complete oxidation of higher levels of thiosulfate (4000–6000 ppm) was achieved in SB and S0 was reclaimed by a maximum of 40% at 6000 ppm thiosulfate. The dominant strain was isolated and identified by 16S rRNA as Ochrobactrum sp. PN1. Although thiosulfate oxidation by this isolate was quite similar to the consortium, S0 formation was higher (195 mg S L−1) by the consortium compared to the isolated strain (138 mg S L−1). Our enriched SOB consortium was therefore well capable of partial oxidation of thiosulfate into S0, a less polluting intermediate product with versatile applications.

The Effects of Biochar on Indigenous Arbuscular Mycorrhizae Fungi from Agroenvironments.

The effects of biochar on soil–plant–microorganisms systems are currently being extensively investigated. Considering that arbuscular mycorrhizal fungi (AMF) play an essential role in nutrient dynamics, the present study aims at understanding vine shoot-derived biochar effects on AMF activity and the impact of their multiplication in soils on water-stress resistance of plants. Three agronomic tests were performed in greenhouse pots. The first experiment evaluated the effects of three factors: final pyrolysis temperature for biochar production (400 °C and 600 °C), application rate (0 weight-wt.- % as a control, 1.5 wt. %, and 3.0 wt. %) and texture of the growing media (sandy-loam and clay-loam origin) on AMF, microbial communities and phosphatase activity. In the second experiment, an indigenous consortium of AMF was multiplied through the solid substrate method and sorghum as a trap plant with biochar addition. This process was compared to a control treatment without biochar. Obtained inocula were tested in a third experiment with lettuce plants under different water irrigation conditions. Results from the first experiment showed a general increase in AMF activity with the addition of the biochar produced at 400 °C in the sandy-loam texture substrate. Results of the second experiment showed that the biochar addition increased AMF root colonization, the number of AMF spores and AMF infective potential. Results of the third experiment showed that biochar-derived AMF inoculum increased AMF root colonization, AMF spores, dry biomass and the SPAD index in a lettuce crop under low-water irrigation conditions.

Degradation performance and microencapsulation of hydrolytic bacterial consortium formulated as bioremediation agent of liquid biomedical waste

This study aimed to develop bioremediation agent with bacterial cells as components for the treatment of biomedical wastes from two hospitals in Semarang City (Central Java), i.e. Roemani Muhammadiyah (coded R1) and Wongsonegoro (coded R2). Single isolates and consortium of indigenous hydrolytic bacteria characterized as multiple hydrolytic enzyme producers with low-to non-pathogenic properties obtained from previous study were tested for their degradation performance. The degradation performance test is necessary to formulate components of bacterial consortium as bioremediation agent. The tests were conducted on the selected bacteria as single isolate and as consortium. The six bacteria tested as single colonies and as consortium were Bacillus velezensis R1.3, B. amyloliquefaciens R1.6, B. amyloliquefaciens R1.14, B. velezensis R1.16, B. licheniformis R2.5, and B. amyloliquefaciens R2.9. Degradation performance on biomedical waste mainly containing organic matters was assessed based on water pollution parameters on 4.0-L samples. They included a control, 6 samples treated with bacteria as single colonies, a sample treated with bacteria as indigenous consortium and a sample treated with bacteria as mixed consortium. Parameters of wastewater pollution measured included COD (Chemical Oxygen Demand), BOD (Biological Oxygen Demand), TSS (Total Soluble Solid), NH3, and PO4. Next, encapsulation of a bacterial consortium as the best condition for degradation was also carried out using maltodextrin to allow storage and preservation of the bioremediation agent for longer period. The encapsulated product was visualized in SEM images to evaluate its quality. The results showed that a consortium comprising 4 indigenous bacterial isolates from R1 hospital could decrease BOD of biomedical wastewater by 85% and TSS by 43%. Those from R2 showed performance in reducing PO4 by 21%. This study demonstrated that compared to single isolates and mixed bacterial consortium tested, the indigenous hydrolytic bacterial consortium showed better ability in improving BOD and TSS of liquid biomedical waste of R1 hospital.

Hydroponic Farm Wastewater Treatment Using an Indigenous Consortium

Hydroponic farms produce wastewater that need to be treated before being released into the environment. A three-step screening process (microplate, batch, and semi-continuous flasks experiments) initially designed to select an efficient microalgae strain allowed the isolation of a consortium that naturally developed in the hydroponic farm wastewater. During the non-optimized semi-continuous experiments, the best performing microalgae strain, Scenedesmus obliquus UTEX393 and the wastewater-born consortium cultures achieved good average linear growth rate (0.186 and 0.198/d, respectively) and high average nitrogen removal rates (23.5 mgN/L/d and 21.9 mgN/L/d, respectively). Phosphorus removal was very high probably due to precipitation. An integrated process was designed to treat the hydroponic farm wastewater using the wastewater-born consortium. Despite relatively low coagulation efficiencies in the preliminary tests, when integrated in a continuous process, chitosan was efficient to harvest the naturally wastewater-born consortium. The process was also efficient for removing nitrate and phosphate in less than seven days (average removal of 98.2 and 87.1% for nitrate and phosphate, respectively). These very promising results will help to define a pre-industrial pilot process.

Effect of introduction of exogenous strain Leptospirillum ferriphilum YSK on functional gene expression, structure, and function of indigenous consortium during pyrite bioleaching

Leptospirillum ferriphilum YSK was added to a native consortium of bioleaching bacteria including Acidithiobacillus caldus, A. thiooxidans, A. ferrooxidans, Sulfobacillus thermosulfidooxidans, Acidiphilium spp., and Ferroplasma thermophilum cultured in modified 9K medium containing 0.5% (W/V) pyrite. The bioleaching efficiency markedly increased. Changes in community structure and gene expression were monitored with real-time PCR and functional gene arrays. Dynamic changes that varied in different populations in the consortium occurred after the addition of L. ferriphilum YSK, with growth of A. caldus S1, A. thiooxidans A01, Acidiphillum spp. DX1-1 promoted the growth of Ferroplasma L1, inhibited that of S. thermosulfidooxidans ST, and exerted little effect on that of A. ferrooxidans CMS. Genes encoding ADP heptose, phosphoheptose isomerase, glycosyltransferase, biotin carboxylase, and protoheme ferrolyase from L. ferriphilum, acetyl-CoA carboxylase from Acidiphillum spp., and doxD from A. caldus were up-regulated in 0–20 h. Genes encoding lipid A disaccharide synthase LpxB, glycosyl transferase, and ADP heptose synthase from A. ferrooxidans were up-regulated in 0–8 h and then down-regulated in 8–20 h. Genes encoding ferredoxin oxidoreductase from Ferroplasma sp. were up-regulated in 0–4 h, down-regulated in 4–16 h, and again up-regulated in 16–20 h. CbbS from A. ferrooxidans was down-regulated in 0–20 h.

Non-sterile fermentation of food waste with indigenous consortium and yeast – Effects on microbial community and product spectrum

This work presents examples of non-sterile mixed culture fermentation of food waste with a cultivated indigenous consortium (IC) gained from food waste, which produces lactic and acetic acids, combined with Saccharomyces cerevisiae, which produces ethanol. All results are flanked by microbial analysis to monitor changes in microbial community. At pH 6 and inoculated with yeast or IC, or both mixed sugars conversion was equal to 71%, 51%, or 67%, respectively. Under pH unregulated conditions metabolic yields were 71%, 67%, or up to 81%. While final titer of acetic acid was not affected by pH (100–200 mM), ethanol and lactic acid titers were. Using mixed culture and pH 6, sugars were almost equally used for formation of ethanol and lactic acid (400–500 mM). However, under pH unregulated conditions 80% of the substrate was converted into ethanol (900–1000 mM).

Techno-economic assessment of non-sterile batch and continuous production of lactic acid from food waste

Non-sterile lactic acid (LA) fermentation of highly viscous food waste was demonstrated in batch and continuous flow fermentations. With Streptococcus sp., an indigenous consortium, and/or applied glucoamylase, food waste was fermented without addition of external carbon or nitrogen sources. Experimental results were used for economic and energy evaluations under consideration of different catchment area sizes from 50,000 to 1,000,000 inhabitants. During batch mode, addition of glucoamylase resulted in a titer (after 24 h), yield, and productivity of 50 g L−1, 63%, and 2.93 g L−1h−1, respectively. While titer and yield were enhanced, productivity was lower during continuous operation and 69 g L−1, 86%, and 1.27 g L−1h−1 were obtained at a dilution rate of 0.44 d−1 when glucoamylase was added. Both batch and continuous flow fermentations were found economically profitable with food waste from 200,000 or more inhabitants.

Evaluating the potential of indigenous methanogenic consortium for enhanced oil and gas recovery from high temperature depleted oil reservoir

In past years, lots of research has been focused on the indigenous bacteria and their mechanisms, which help in enhanced oil recovery. Most of the oil wells in Indian subcontinent have temperature higher than 60 °C. Also, the role of methanogenic consortia from high temperature petroleum reservoir for enhanced oil recovery (EOR) has not been explored much. Hence, in the present study methanogens isolated from thermophilic oil wells (70 °C) were evaluated for enhanced oil recovery. Methane gas is produced by methanogens, which helps in oil recovery from depleted oil wells through reservoir re-pressurization and also can be recovered from reservoir along with crude oil as alternative energy source. Therefore, in this study indigenous methanogenic consortium (TERIL146) was enriched from high temperature oil reservoir showing (12 mmol/l) gas production along with other metabolites. Sequencing analysis revealed the presence of Methanothermobacter sp., Thermoanaerobacter sp., Gelria sp. and Thermotoga sp. in the consortium. Furthermore, the developed indigenous consortium TERIL146 showed 8.3% incremental oil recovery in sandpack assay. The present study demonstrates successful recovery of both oil and energy (gas) by the developed indigenous methanogenic consortium TERIL146 for potential application in thermophilic depleted oil wells of Indian subcontinent.

Bioaugmentation of chlorothalonil-contaminated soil with hydrolytically or reductively dehalogenating strain and its effect on soil microbial community

Although bioaugmentation of pollutant-contaminated sites is a great concern, there are few reports on the relationships among indigenous microbial consortia, exogenous inocula, and pollutants in a bioaugmentation process. In this study, bioaugmentation with Pseudochrobactrum sp. BSQ1 and Massilia sp. BLM18, which can hydrolytically and reductively dehalogenate chlorothalonil (TPN), respectively, was studied for its ability to remove TPN from soil; the alteration of the soil microbial community during the bioaugmentation process was investigated. The results showed that TPN (50 mg/kg) was completely removed in both bioaugmentation treatments within 35 days with half-lives of 6.8 and 9.8 days for strains BSQ1 and BLM18 respectively. In high concentration of TPN-treated soils (100 mg/kg), the bioaugmentation with strains BSQ1 and BLM18 respectively reduced 76.7% and 62.0% of TPN within 35 days. The TPN treatment significantly decreased bacterial richness and diversity and improved the growth of bacteria related to the elimination of chlorinated organic pollutants. However, little influence on soil microbial community was observed for each inoculation treatment (without TPN treatment), showing that TPN treatment is the main force for the shift in indigenous consortia. This study provides insights into the effects of halogenated fungicide application and bioaugmentation on indigenous soil microbiomes.