Autochthonous Microorganisms Research Articles

Experimental simulation of H2 coinjection via a high-pressure reactor with natural gas in a low-salinity deep aquifer used for current underground gas storage.

If dihydrogen (H2) becomes a major part of the energy mix, massive storage in underground gas storage (UGS), such as in deep aquifers, will be needed. The development of H2 requires a growing share of H2 in natural gas (and its current infrastructure), which is expected to reach approximately 2% in Europe. The impact of H2 in aquifers is uncertain, mainly because its behavior is site dependent. The main concern is the consequences of its consumption by autochthonous microorganisms, which, in addition to energy loss, could lead to reservoir souring and alter the petrological properties of the aquifer. In this work, the coinjection of 2% H2 in a natural gas blend in a low-salinity deep aquifer was simulated in a three-phase (aquifer rock, formation water, and natural gas/H2 mix) high-pressure reactor for 3 months with autochthonous microorganisms using a protocol described in a previous study. This protocol was improved by the addition of protocol coupling experimental measures and modeling to calculate the pH and redox potential of the reactor. Modeling was performed to better analyze the experimental data. As in previous experiments, sulfate reduction was the first reaction to occur, and sulfate was quickly consumed. Then, formate production, acetogenesis, and methanogenesis occurred. Overall, H2 consumption was mainly caused by methanogenesis. Contrary to previous experiments simulating H2 injection in aquifers of higher salinity using the same protocol, microbial H2 consumption remained limited, probably because of nutrient depletion. Although calcite dissolution and iron sulfide mineral precipitation likely occurred, no notable evolution of the rock phase was observed after the experiment. Overall, our results suggested that H2 can be stable in this aquifer after an initial loss. More generally, aquifers with low salinity and especially low electron acceptor availability should be favored for H2 costorage with natural gas.

Oil Spill Mitigation with a Team of Heterogeneous Autonomous Vehicles

This paper presents the implementation of an innovative solution based on heterogeneous autonomous vehicles to tackle maritime pollution (in particular, oil spills). This solution is based on native microbial consortia with bioremediation capacity, and the adaptation of air and surface autonomous vehicles for in situ release of autochthonous microorganisms (bioaugmentation) and nutrients (biostimulation). By doing so, these systems can be applied as the first line of the response to pollution incidents from several origins that may occur inside ports, around industrial and extraction facilities, or in the open sea during transport activities in a fast, efficient, and low-cost way. The paper describes the work done in the development of a team of autonomous vehicles able to carry as payload, native organisms to naturally degrade oil spills (avoiding the introduction of additional chemical or biological additives), and the development of a multi-robot framework for efficient oil spill mitigation. Field tests have been performed in Portugal and Spain’s harbors, with a simulated oil spill, and the coordinate oil spill task between the autonomous surface vehicle (ASV) ROAZ and the unmanned aerial vehicle (UAV) STORK has been validated.

Autochthonous bioaugmentation strategies for the successful bioremediation of high-salt petrochemical wastewater using a biosurfactant-producing Enterobacter cloacae Z11

Petrochemical wastewater contains a high concentration of refractory aliphatic and aromatic hydrocarbons. Bioremediation of these hazardous materials using autochthonous bioaugmentation (ABA) strategy is attracting increasing interest. Herein, an indigenous biosurfactant-producing bacteria Z11 was isolated and identified as Enterobacter sp. The reintroduction of Z11 into petrochemical wastewater led to a substantial reduction (P < 0.01) in TPHs, decreasing from 8099 to 1723 mg/L, as well as a significant decrease in COD, decreasing from 8064.2 to 1689.2 mg/L. At a critical micelle concentration of 200 mg/L, the biosurfactant synthesized by Z11 exhibited an extraordinary decrease in surface tension from 67.5 to 29 mN/m. The biosurfactant demonstrated favorable surface activity over a wide pH, temperature, and salinity range. Based on a series of chemical analyses, the biosurfactant was classified as phospholipid. The autochthonous bioaugmentation technique developed by Z11 indicated a significant increase (P < 0.05) in the degradation of n-alkanes of varying chain lengths and polycyclic aromatic hydrocarbons. The analysis of the microbial composition demonstrated that the addition of Z11 caused a rise in bacterial populations capable of hydrocarbon decomposition, such as Pseudomonas sp. and Stenotrophomonas sp. The activities of two enzymes involved in degradation, alkane hydroxylase and alcohol dehydrogenase, increased dramatically and showed a significant (P < 0.05) correlation with Enterobacter sp. Z11. The proposed mechanism could be elucidated that functional genes regulate the secretion of biodegradation enzymes and biosurfactants to promote the deep degradation of petroleum hydrocarbons. This study provides technical support for the reintroduction of autochthonous microorganisms capable of producing biosurfactants in implementing in situ ABA strategies.

Microbiological treatment of post-industrial water: Example of efficient bioremediation of the heavily polluted Kalina pond, Poland

The Kalina pond has been well known as a severely degraded area in the Silesia region, Poland. The environmental deterioration results from high contamination of water and bottom sediments with recalcitrant and toxic organic compounds, mainly phenol. The study was aimed at developing a bioremediation-based approach suitable for this type of polluted areas, involving microbiological treatment of water as a key and integral part of other necessary actions: mechanical interventions and the use of physical methods. During the initial biological treatment stage, autochthonous microorganisms were isolated from contaminated samples of water, soil and sediment, then subjected to strong selective pressure by incubation with the pollutants, and finally, cultivated to form a specialised microbial consortium consisting of five extremophilic bacterial strains. Consortium propagation and its biodegradation activity were optimised under variant conditions enabling bacteria to proliferate and to obtain high biomass density at large volumes allowing for the in situ application. After installing aeration systems in the pond, the consortium was surface-sprinkled to launch bioremediation and then both bacterial frequency and the contaminant level was systematically monitored. The complex remediation strategy proved efficient and was implemented on an industrial scale enabling successful remedial of the affected site. Treatment with the specifically targeted and adapted microbial consortium allowed for removal of most organic pollutants within a four-month season of 2022: the chemical oxygen demand (COD) value decreased by 72%, polyaromatic hydrocarbon (PAH) level by 97%, while the content of total phenols and other monoaromatic hydrocarbons (BTEX) dropped below the detection thresholds.

Comparative study of three H2 geological storages in deep aquifers simulated in high-pressure reactors

Massive storage of dihydrogen (H2) in underground geological storage (UGSs) will be necessary to meet future H2 production ambitions. Such storage in deep aquifers was simulated in a high-pressure reactor, and the evolution of the 3 phases (natural gas/H2, formation water and rock) with autochthonous microorganisms was monitored over several weeks. These results show that methanogens do not necessarily dominate the community, but that sulfate-reducing activity and formate bioproduction are systematically present. The experimental data were fed into a biochemical model in PHREEQC to better understand the interplay between the phenomena observed. In particular, it was shown that the microbial activities associated with H2 consumption led to alkalinisation, which could explain, at least in part, the slower rate at which H2 disappeared, even if sufficient CO2 and sulfate remained in the system. Combined with a supposed local nutrient depletion, these results are encouraging for H2 storage in deep aquifers.

Correlation between monosaccharide, oligosaccharide, and microbial community profile changes in traditional soybean brick (meju) fermentation

Meju is essential for making diverse traditional fermented soybean foods in Korea. To understand the changes in carbohydrates during fermentation, we aimed to identify autochthonous microorganisms from spontaneously fermented meju and compare the alterations in monosaccharides and oligosaccharides throughout the fermentation process. Microbial diversity was determined using a metabarcoding approach, and monosaccharide and oligosaccharide profiles were obtained by HPLC-Q-TOF MS and HPLC-MS/MS analyses, respectively. The dominant bacterial genera were Weissella, Lactobacillus, and Leuconostoc, while Mucor was highly abundant in the fungal community. The total monosaccharide content increased from Day 0 to Day 50, with the highest amount being 4.37 mg/g. Oligosaccharide profiling revealed the degradation of soybean dietary fiber during fermentation, and novel oligosaccharide structures were also discovered. Correlation analysis revealed that the fungus Mucor was positively related to pentose-containing oligosaccharides, galactose, and galacturonic acid, indicating that Mucor may degrade soybean dietary fibers such as xylogalacturonan, arabinogalactan, and rhamnogalacturonan. The negative relationships between the abundances of Weissella and oligo- and monosaccharides suggested that the bacteria may utilize saccharides for fermentation. These findings provide insights into the mechanisms underlying carbohydrate degradation and utilization; the key components involved in saccharide transformation that contribute to the characteristics of traditional meju were subsequently identified.

Biotechnological Potential of Oil-Tolerant Strains for Possible Use in Bioremediation

The release of oil into the environment represents a pervasive problem stemming from oil exploration, accidents, transportation and releases from landfills, storage facilities or industrial plants. Compared to conventional and costly techniques, bioremediation is an attractive and promising alternative, as it can selectively degrade pollution without affecting the natural features of the site and the flora and fauna living there. In this study, the isolation, identification and characterization of autochthonous bacterial strains from a crude oil-contaminated soil sample was carried out under batch conditions over a period of 28 days. The initial colony forming units value for bacteria was 1.15 × 109/g of soil. The results show that the activity of bacteria was highest at a pH of 7.25. Based on morphology, biochemical tests and an analysis of MALDI TOF, isolated autochthonous bacterial species were identified as Bacillus megaterium, Bacillus licheniformis, Bacillus cereus and Pseudomonas chlororaphis. Since allochthonous bacteria are not highly efficient in a new environment due to their low adaptability and competition with indigenous microorganisms, these autochthonous microorganisms play a pivotal role in enhancing the bioremediation process on an applicable, industrial scale. This advancement aligns with the principles of sustainable development and the green economy, as purified soil is suitable for rational reuse in the environment.

Assessment of the water quality of Lake Baikal and its tributaries in areas affected by local pollution based on microbiological and hydrochemical data

The water quality of Lake Baikal and its tributaries, influenced by seven different local pollution sources, was assessed in the areas of wastewater discharge from wastewater treatment plants (WWTPs) of the towns of Slyudyanka, Baikalsk, and Severobaikalsk, as well as domestic wastewater discharge from tourist resorts and Maksimikha settlement, runoff of hot springs from thermal baths in Zmeinaya Bay, Baikal seal rookeries, and the tourist center on Tonky Island of the Ushkanyi Islands archipelago in September 2022. The waters of the lake and the Rivers Pokhabikha, Maksimikha, and Tyya using microbiological and hydrochemical analysis methods are assessed as clean II class quality (GOST 17.1.3.07-82), except for the coastal water zone opposite the mouth of the Pokhabikha River, where the water is defined as moderately polluted. The unequal distribution of the values of the self-purification coefficient indicates a high abundance of microflora of allochthonous origin and a low activity of autochthonous microorganisms involved in self-purification processes in the studied areas of the lake. It was found that wastewater discharged by treatment facilities; water at the mouth and surface water of the Baikal in the estuary of the Pohabikha River, water in thermal baths of hot springs in Zmeinaya Bay do not meet the requirements of SanPiN 1.2.3685-21 for the maximum permissible amount of generalized coliform bacteria, Escherichia coli and Enterococcus. At all control stations in the pelagic zone of Lake Baikal, remote from the studied local polluted sites, water quality indicators did not exceed the safety water standards for surface water bodies in terms of microbiological and hydrochemical parameters.

Geochemistry and metagenomics analyses of bacterial community structure in selected waste dumpsites in Lagos Metropolis, Nigeria

Dumpsites are reservoirs of persistent organic pollutants (POPs) and heavy metals (HMs), constituting environmental hazards to humanity. Autochthonous microorganisms in dumpsites exhibit various degrees of responses to contaminants. Unfortunately, there is a dearth of information on the types and concentration of pollutants and the array of microorganisms in these dumpsites which may play important roles in the metabolism of such pollutants or other community processes. Therefore, determining the microbial community structure in such contaminated sites across a municipality is essential for profiling the taxa that would serve as consensus degraders of the pollutants. In this study, soil samples from three dumpsites (Cele, CS; Solous, SS; and Computer Village, CVS) were characterized for geochemical properties using GC-MS, MP-AES, and other analytical protocols, while the dynamics of bacterial communities were evaluated based on their 16S rRNA gene barcodes. A significant difference in the bacterial communities was observed among the dumpsites in relation to the extent of pollution caused by POPs and HMs. CVS, with the highest HM contamination, was rich in Actinobacteria (41.7%) and Acidobacteria (10.2%), in contrast to CS and SS. Proteobacteria (34.1%) and Firmicutes (20%) were the dominant phyla in CS (highest POP contamination), while Bacteroidetes (45.5%) and Proteobacteria (39.9%) were dominant in SS soil. Bacillus was the dominant genus in the most polluted dumpsite. Canonical correspondence analysis revealed that polycyclic aromatic hydrocarbons (PAHs) and HMs shaped the structure of the bacterial operational taxonomic units (OTUs) in the most polluted dumpsite. Out of a total of 706 OTUs, 628 OTUs exhibited a significant correlation (&amp;gt;50%) with benzo(b)fluoranthene, azobenzene, dibenzofurans, pyrene, dibenzo(a,l)pyrene, Cu, and Zn. In particular, Proteobacteria (Achromobacter sp. and Serratia sp.), Bacteroidetes (Zhouia sp.), and Firmicutes (Bacillus sp.) were suggested to be pivotal to the ecophysiology of dumpsite soils contaminated with POPs and HMs. The results generally underscored the importance of metagenomic and physicochemical analyses of polluted systems in enabling correlations for useful prediction of drivers of such ecosystems. This will further improve our understanding of the metabolic potential and adaptation of organisms in such systems.

BIOCONVERSION OF MEAT PROCESSING FATTY WASTE USING YEAST Y.LIPOLYTICA

A technology for the utilization of fat waste from meat processing based on a combination of physical and chemical effects and biological oxidation is proposed. The main chemical and microbiological parameters of the fat-containing phase of effluents of meat processing enterprises were determined. It was established that in the process of holding waste in a sludge collector (1…13 days) as a result of the vital activity of autochthonous microorganisms, the fat content decreases from 87 % to 58 %. The dominant organism of the autochthonous microflora of the waste is the fungus Geotrichum.sp. It was established that Yarrowia lipolytica yeast, selected for the substrate, is the most promising fat biodestructor. A method of pretreatment of the fat-containing solid phase of fatty effluents has been developed, which increases the efficiency of their consumption by the Yarrowia lipolytica culture. The basis of the method is the ultrasonic dispersion of fat mass, as a result of which the bioavailability of the substrate increases and, as a result, the specific growth rate and yield of microbial biomass increases by 11 % and 30 %, respectively. The methods of seed preparation are proposed, which allow to increase the efficiency of the main process according to the indicators: biomass yield (by 10.1 %); specific growth rate (from 0.20 to 0.26 h–1); protein content (by 16.7 %). The methods include the selection (5…7 passages) of high-performance clones, which is carried out in the directions of increasing affinity to the substrate and stress resistance to the action of hydrogen peroxide (2.5 g/l). The obtained results showed that when using yeast Yarrowia lipolytica for the biodestruction of fatty effluents, it is advisable to use both top-up and continuous methods of cultivation, which do not lead to significant changes in the quality of the obtained biomass. Yeast leaching was not observed in the top-up mode at 24 % withdrawal of culture liquid per hour, and in the case of continuous mode - at a flow rate of 0.24 h–1, while the protein and lipid content was 42.7 % and 7.2 %, 41.4 % and 7.9 %, respectively.

Unravelling the modes of action of autochthonous staphylococci against Aspergillus westerdijkiae and the antiochratoxigenic effect in dry-cured ham

Aspergillus westerdijkiae is well known for its capacity to produce high amounts of ochratoxin A (OTA) in dry-cured ham. Some autochthonous microorganisms, such as Staphylococcus xylosus FHSCC Sx8 and Staphylococcus equorum FHSCC Se31 have antifungal effect and can be used as biocontrol agents (BCAs) to reduce the OTA contamination. The aims of this work were to reveal their modes of action against A. westerdijkiae MUM 16.142 in a dry-cured ham model system and validate the antifungal effect in dry-cured ham. As well as to assess the effect of live cells, dead cells, and cell-free broth; the pattern of nutrient use, the niche overlap index (NOI), interactions by dual culture assays, the antifungal activity of volatile compounds, and their effect on the fungal proteome. Both cocci in the dual-culture assay were able to decrease the A. westerdijkiae growth, but only S. xylosus reduced the OTA production at 20 °C. Moreover, changes in the abundance of proteins related to cell wall integrity, secondary metabolite production and carbohydrate metabolism were observed. Furthermore, the anti-A. westerdijkiae effect of S. xylosus was validated in dry-cured ham since this coccus was able to reduce the OTA production in this meat product.

Assessment of the in situ biomethanation potential of a deep aquifer used for natural gas storage

In response to the challenges of sustainable development and the H2 sector, it is foreseeable that H2 will be stored into geological storage, such as deep aquifers. However, CO2 evolves in deep aquifers because it may be naturally present there; it may also be a constituent of the stored gas mix, or could even be voluntarily stored in the context of the fight against global warming. Autochthonous microorganisms can consume them as sources of energy and carbon (methanogens, (homo)-acetogens and sulfate-reducers). This was already demonstrated in a previous experiment (Haddad 2022) and under operating conditions (Lobodice, Czech Republic ; Smigan 1990). Understanding these mechanisms and quantifying them appear necessary to assess the modifications generated by this type of microorganisms on the properties of the gas. The methanogenesis reaction (CO2 gas + 4H2 gas → CH4 gas + 2H2O liquid) induces a lowering of pressure, since 5 gas molecules are transformed into a single gas molecule: CH4 (water being condensed at subsurface conditions). In situ biomethanation technique could represent a potential on several scales larger than conventional catalytic or biological methanation reactors, due to the very large reservoir volumes involved. Biomethanation in geological reservoirs would enable us to reduce our consumption of fossil fuels, so as not to emit more CO2, while meeting the growing energy needs of a region and ensuring its independence from hydrocarbon-producing countries. A deep aquifer already used as UGS was selected for this study. Formation waters from 17 control wells in this aquifer (Fig. 1) were sampled to assess the potential activity of indigenous methanogenic populations, as well as sulfate-reducers. Despite relatively low sulfate concentrations for a deep aquifer (0.025-1.35 mM), sulfate reducers were found at all sites targeting and quantifying the dsrB gene, which is characteristic of this metabolic group (between 1.8∙101 ±2.0x100 and 1.3∙104 ±2.0∙103 dsrB gene copy numbers.mL-1). In contrast, methanogenic archaea based on the mcrA gene quantification were detected at only 10 of the 17 sites (up to 4.3∙102 ±8.3∙101 mcrA gene copy numbers.mL-1). The choice was made to focus the rest of the study on 7 of these 10 sites. The potential for methanogenesis was assessed on cultural tests with formation water alone or supplemented with calcite (CaCO3), a mineral present in the formation. Results indicate that initial times and controls are controlled by the sulfate variable, since the latter was not consumed by sulfate-reducers. Biotic trials in the presence of calcite and H2/CO2 (abiotic controls and final times) are logically characterized by higher concentrations of calcite, bicarbonate and calcium, but this is not the case for trials in the presence of H2 alone. We therefore deduce that methanogenesis took place mainly via gaseous CO2, but that without the latter, calcite was a source of carbon for lithoautotrophs. Cultures incubated with H2 as the sole gas phase have the highest methane concentrations, logically associated with the lowest sulfate concentrations (consumed by sulfate-reducers), the lowest Eh (probably due to the presence of sulfides) and more alkaline pH values up to 10 (which may have led to precipitation of carbonate and calcium ions). All the sites studied showed sulfate consumption and methane production. Analysis of taxonomic diversity (MiSeq; 16S rRNA gene V4-V5) showed the dominance of three genera of sulfate-reducers with Thermodesulfovibrio-Desulfovibrio-Desulfotomaculum and methanogenic populations belonging to the Methanobacterium genus. These initial results show a strong potential of in situ biomethanation for the deep aquifer studied. All these experiments were carried out at near-atmospheric pressure, and the results still need to be confirmed and refined in the laboratory under conditions that simulate real-life conditions as closely as possible (rock, pressure, nature of gases).

Effect of Commercial and Autochthonous Bioprotective Cultures for Controlling Listeria monocytogenes Contamination of Pecorino Sardo Dolce PDO Cheese.

The composition and physicochemical characteristics of short-aged Pecorino Sardo PDO (Protected Designation of Origin) cheese makes it permissive to Listeria monocytogenes growth. The PDO product specification stipulates that this cheese is produced with whole sheep's milk inoculated with cultures from the area of origin. Therefore, the use of bioprotective cultures for the inhibition of pathogens in PDO cheeses is allowed only if autochthonous microorganisms are used. Furthermore, bioprotective cultures are generally used on the cheese surface to prevent the outgrowth of L. monocytogenes, the application of which can be time-consuming and require specialist technical knowledge. In this study, we examine the direct addition of bioprotective cultures to the cheese vat and compare the activity of a commercial bioprotective culture (Lactiplantibacillus plantarum) and an autochthonous lactic acid bacterium with bioprotective properties (Lactobacillus delbruekii sups. sunkii), for the inhibition of L. monocytogenes in Pecorino Sardo PDO cheese. Three types of Pecorino Sardo PDO cheese were made with bioprotective cultures added directly to the cheese milk along with the starter inoculum: PSA, with the commercial bioprotective culture; PSB, with the autochthonous bioprotective culture; and a CTRL cheese with no bioprotective culture. A challenge test was performed on each of these cheeses by artificially contaminating the cheese surface with L. monocytogenes (2 Log10 CFU/g). Three batches of each cheese type were analyzed to enumerate mesophilic and thermophilic lactic acid bacteria and to investigate the growth potential of L. monocytogenes during manufacturing, at the end of ripening, at the end of shelf-life, and after 180 days from cheese production. Both bioprotective cultures tested in this study showed inhibitory action against the pathogen with 0.3-1.8 Log10 CFU/g (colony-forming unit per gram) reduction levels. The autochthonous organism, L. sunkii, was as effective as the commercially supplied culture, and the addition of the bioprotective cultures to the cheese-making procedure offered protection against L. monocytogenes. The direct addition of bioprotective cultures to the making procedure of Pecorino Sardo PDO cheese is a potentially innovative strategy to improve the safety of this product.

Microbial activities along a 20 million-year-old pristine oil reservoir

Studies on oil reservoir microbiology typically take samples from producing reservoirs and sample fluids that have been pumped to the surface. This comes with problems since producing oil reservoirs are affected by production processes leading to changes in environmental conditions and the natural microbiome. Hence, pumped samples do not display an unaltered picture of the spatial distribution and composition of the microorganisms in the reservoir. We took 13 samples from a freshly drilled sediment core of a pristine, heavily biodegraded oil reservoir in the North Sea. Core samples originated from above, within, and below the reservoir. 16S rRNA gene amplicon sequencing of the microbiome revealed distinct differences between sediments and formation water, indicating that studies on microbiomes from formation water alone are not necessarily representative for the microbial processes in an oil reservoir. Fluorescence microscopy showed that microorganisms live in small microcolonies on the sediment surface. CT-scanning with image analysis visualized the water phase distribution inside the reservoir sediments and clearly indicated water-filled voids that might be habitable for microorganisms, enlarging the surface for potential biodegradation. Employing microcosm experiments and reverse isotope labelling, we were able to determine the first degradation rates measured from cores above, within, and below a reservoir ranging from no activity up to 1 mM CO2/(gsediment x year), Results indicate significant degradation potential from autochthonous microorganisms in the reservoir above the water-contact-zone. Evading the general issues of produced oil samples for studying microbiomes results in a more realistic picture of an oil reservoir unaffected by production artefacts.

Poultry manure-derived microorganisms as a reservoir and source of antibiotic resistance genes transferred to soil autochthonous microorganisms

Animal husbandry is increasing yearly due to the growing demand for meat and livestock products, among other reasons. To meet these demands, prophylactic antibiotics are used in the livestock industry (i.e., poultry farming) to promote health and stimulate animal growth. However, antibiotics are not fully metabolized by animals, and they are evacuated to the environment with excreta. Animal manure is used as fertilizer to reduce the volume of waste generated in the livestock sector. However, manure often contains microorganisms harboring antibiotic resistance genes (ARGs). Then, the microbiome of manure applicate to the soil may contribute to the spread of antibiotic resistance in the environment, including autochthonous soil-dwelling microorganisms. The present study was conducted during the crops growing season in Poland (May to September 2019) to determine the influence of poultry manure as well as poultry manure supplemented with selected antibiotics on the diversity of the soil microbiome in treatments that had not been previously fertilized with manure and the ability of antibiotic-resistant bacteria to transfer ARGs to other soil bacteria. Antibiotic concentrations were elevated at the beginning of the study and decreased over time. Poultry manure induced significant changes in the structure of microbial communities in soil; the diversity of the soil microbiome decreased, and the abundance of bacterial genera Bradyrhizobium, Streptomyces, and Pseudomonas, which are characteristic of the analyzed manure, increased. Over time, soil microbial diversity was restored to the state observed before the application of manure. Genes conferring resistance to multiple drugs as well as genes encoding resistance to bacitracin and aminoglycosides were the most frequently identified ARGs in the analyzed bacteria, including on mobile genetic elements. Multidrug resistance was observed in 17 bacterial taxa, whereas ARGs were identified in 32 bacterial taxa identified in the soil microbiome. The results of the study conclude that the application of poultry manure supplemented with antibiotics initially affects soil microbiome and resistome diversity but finally, the soil shows resilience and returns to its original state after time, with most antibiotic resistance genes disappearing. This phenomenon is of great importance in sustainable soil health after manure application.

Performance of clostridium species and autochthonous bacteria from citrus wastewater under different carbon sources to produce biofuels

This study evaluated the energy recovery of citrus wastes with pure cultures (Clostridium acetobutylicum ATCC 824, Clostridium beijerinckii ATCC 10132 – Inocula 1 and 2, respectively) and an autochthonous microbial (Inoculum 3) from citrus wastewater (CW) in anaerobic batch reactors to produce biofuels (H2 and ethanol) fed with different carbon sources (glucose, maltose, fructose, sucrose, xylose, lactose, starch, acetate, and glycerol) in addition to CW. 4 conditions are tested: 1st - Inoculum 3, composed by Bacillus (20.44%), Clostridium (13.65%) and Lactobacillus (10.61%) was able to produce H2 with sucrose, glucose and fructose. 2nd - The highest metabolites were produced with TYA medium with Inocula 1 (374 mg L−1 of acetic acid) and 2 (611 mg L−1 of butanol). Inoculum 3 generated the highest ethanol (1571.8 mg L−1) in PYG medium. 3rd - In the same nutritional conditions (PYG), Inocula 1 and 2 produced H2 (36.80 and 64.10 mmol L−1, respectively) and acetic acid (246 and 201 mg L−1, respectively); the H2 was suppressed with inoculum 3 due to Lactobacillus genus. 4th H2 production was favored by autochthonous bacteria in CW. This study valued the autochthonous microorganisms in the possibility of bioconversion of organic matter into value-added products in addition to contribute to an environment-sustainable solution for citrus processing.

Isolation and characterization of some autochthonous microorganisms from dumpsite leachates in Ogun State, Nigeria

Municipal solid wastes are materials generated through man's daily needs and used for life sustainability that presumably regarded as unwanted to individuals. Soil microorganisms, fungi and bacteria are known to colonize the waste, the degradation and transformation of biodegradable materials in the waste contents. The physical and chemical assessment of the leachate samples parameters measured were the hydrogen ion concentration (pH), Total Dissolved Solids (TDS), and electrical conductivity (EC) parameters, and metals such as K+, Ca2+, Mg2+, Na+, Cl-, NO3-, SO42-, and PO43-. The Aliquots from each leachate-filled bottle were drawn with a sterile pipette and used for isolating the bacterial and fungal ecology aseptically. One-milliliter of leachate samples were poured into 9 ml of distilled water and mixed thoroughly. Serial dilutions were made at 10-1 to 10-5 for the bacteria. The same dilution levels for fungi, were cultured using the pour plate method on Potato Dextrose Agar (PDA) to determine heterotrophic fungi (HF) in the leachate. The physical and chemical parameters of the leachate are Temp (℃), 27.00; pH 8. 5; TDS (mg/L), 280; BOD (mg/L), 11; EC (μS/cm), 632; K+ (mg/L, 26; Ca2+ (mg/L), 170; Mg2+ (mg/L), 32; Na+ (mg/L), 12; Cl- (mg/L), 121; NO3–(mg/L), 27; SO42- (mg/L), 58; PO43- (mg/L), 132. And the autochthonous microbial contents from the soil and leachate from the dumpsite are similar; vis: Aspergillus flavus, Aspergillus fumigatus, Aspergillus niger, Penicillin sp., Rhizopus sp., Saccharomyces sp., Fusarium sp., Bacillus sp., Micrococcus sp., Corynebacterium Sp. Pseudomonas sp. and Escherichia coli.

Enhancement of Textural and Sensory Characteristics of Wheat Bread Using a Chickpea Sourdough Fermented with a Selected Autochthonous Microorganism.

A traditional Greek sourdough, based on the fermentation of chickpea flour by an autochthonous culture, was evaluated as a wheat bread improver. The dominant indigenous microflora (Clostridium perfringens isolates) was identified by 16S rDNA analysis, and a selected strain (C. perfringens CP8) was employed to ferment chickpea flour to obtain a standardized starter culture (sourdough) for breadmaking. In accordance with toxin-typed strain identification, all isolates lacked the cpe gene; thus, there is no concern for a health hazard. Loaf-specific volumes increased with the addition of liquid, freeze-dried, and freeze-dried/maltodextrin sourdoughs compared to control bread leavened by baker's yeast only. Following storage (4 days/25 °C), the amylopectin retrogradation and crumb hardness changes (texture profile analysis) revealed a lower degree of staling for the sourdough-fortified breads. Modifications in the protein secondary structure of fortified doughs and breads were revealed by FTIR analysis. High amounts of organic acids were also found in the sourdough-supplemented breads; butyric and isobutyric acids seemed to be responsible for the characteristic 'butter-like' flavor of these products (sensory analysis). Overall, the addition of liquid or freeze-dried chickpea sourdough in wheat bread formulations can improve the specific volume, textural characteristics, and sensorial properties of loaves, along with extending bread shelf life.

Oil-Contaminated Soil Remediation with Biodegradation by Autochthonous Microorganisms and Phytoremediation by Maize (Zea mays).

Biological methods are currently the most commonly used methods for removing hazardous substances from land. This research work focuses on the remediation of oil-contaminated land. The biodegradation of aliphatic hydrocarbons and PAHs as a result of inoculation with biopreparations B1 and B2 was investigated. Biopreparation B1 was developed on the basis of autochthonous bacteria, consisting of strains Dietzia sp. IN118, Gordonia sp. IN101, Mycolicibacterium frederiksbergense IN53, Rhodococcus erythropolis IN119, Rhodococcus globerulus IN113 and Raoultella sp. IN109, whereas biopreparation B2 was enriched with fungi, such as Aspergillus sydowii, Aspergillus versicolor, Candida sp., Cladosporium halotolerans, Penicillium chrysogenum. As a result of biodegradation tests conducted under ex situ conditions for soil inoculated with biopreparation B1, the concentrations of TPH and PAH were reduced by 31.85% and 27.41%, respectively. Soil inoculation with biopreparation B2 turned out to be more effective, as a result of which the concentration of TPH was reduced by 41.67% and PAH by 34.73%. Another issue was the phytoremediation of the pre-treated G6-3B2 soil with the use of Zea mays. The tests were carried out in three systems (system 1-soil G6-3B2 + Zea mays; system 2-soil G6-3B2 + biopreparation B2 + Zea mays; system 3-soil G6-3B2 + biopreparation B2 with γ-PGA + Zea mays) for 6 months. The highest degree of TPH and PAH reduction was obtained in system 3, amounting to 65.35% and 60.80%, respectively. The lowest phytoremediation efficiency was recorded in the non-inoculated system 1, where the concentration of TPH was reduced by 22.80% and PAH by 18.48%. Toxicological tests carried out using PhytotoxkitTM, OstracodtoxkitTM and Microtox® Solid Phase tests confirmed the effectiveness of remediation procedures and showed a correlation between the concentration of petroleum hydrocarbons in the soil and its toxicity. The results obtained during the research indicate the great potential of bioremediation practices with the use of microbial biopreparations and Zea mays in the treatment of soils contaminated with petroleum hydrocarbons.

Microorganismos autóctonos como alternativa de biofertilización de Nicotiana tabacum L.

Tobacco is a crop of economic importance in tropical countries; it generates significant income in small agricultural areas. Within the agrotechnical activities that are carried out on this plant, biofertilization with Autochthonous Microorganisms (AM) represents a viable option for production with low inputs. Therefore, the objective of the research was to determine the biofertilizer effect of AM on black tobacco cv. Havana-2000. The experiment was carried out on a farm located in Los Cayos, Yara, Granma, Cuba, during the period November-February/2021. For this, the yield variables and the components were measured in the field. Statistical processing was performed using ANOVA and principal component analysis. The AM recorded four groups of microbes: bacteria (7x1012 CFU.mL-1) Lactobacillus sp. and Rhodopseudomonas sp., the fungi (3x1011 CFU.mL-1) Trichoderma sp., Aspergillus sp. and Penicillium sp., the yeasts (2x1011 CFU.mL-1) Saccharomyces sp. and Candida sp. and the actinomycete Streptomyces sp. (1x1010 CFU.mL-1). In the field, the AM biostimulated between 15 - 82 % of the yield and the components, achieving the best results at the dose of 36 L.ha-1. Finally, the importance of using AM as an organic alternative for tobacco biofertilization is demonstrated.