Isolation of native microorganisms from Shengli lignite and study on their ability to dissolve lignite.

To more greenly and efficiently utilize the abundant lignite resources and explore the microbial degradation and transformation potential of lignite for its environmentally friendly and resourceful utilization, Shengli lignite from the Hulunbuir region of Inner Mongolia, China, was selected as the research subject. Through the dilution plating method and streaking method, 31 native microorganisms were successfully isolated from the Shengli lignite, including 16 bacteria and 15 fungi. After microbial coal dissolution experiments, it was found that certain microorganisms have a significant dissolving effect on lignite, with some bacterial and fungal strains showing strong dissolution capabilities. In particular, the bacterium SH10 Lysinibacillus fusiformis and the fungus L1W Paecilomyces lilacinus demonstrated the best coal-dissolving abilities, with dissolution rates both reaching 60%. The products of microbial dissolution of lignite were analyzed using gas chromatography-mass spectrometry (GC-MS) technology, identifying a variety of small molecular organic compounds, including alkanes, alcohols, esters, and phenols. The results of this study provide a new perspective on the biodegradation of lignite and lay the foundation for the development of new lignite treatment and utilization technologies.

The collaboration and competition between indigenous microorganisms and exogenous anaerobic digester sludge in anaerobic treatment of pickled mustard wastewater at different salinities.

The highly concentrated pickled mustard wastewater presents significant potential for energy recovery, but the stress effect of high osmotic pressure on cell integrity and activity seriously impedes the methane production by anaerobic microorganisms. The survival ability of indigenous microorganisms (IM) in pickled mustard wastewater supports the establishment of anaerobic treatment. Moreover, inoculation of anaerobic digester sludge is a common start-up strategy. However, the effects of exogenous anaerobic sludge on IM are unclear, especially in hypersaline environment. This research aimed to investigate the influence of exogenous anaerobic sludge on the construction, performance, and microbiota at 3% and 5% salinity. And the research focused on the collaboration and competition between exogenous anaerobic sludge and IM. The neutral community model (which explains the formation and evolution of biological communities) indicated that the interaction between exogenous digester sludge microorganisms and IM dominated community assembly. At 3%, the digester sludge collaborated with IM to increase daily COD reduction and biogas production compared with IM group. However, at 5%, the competitive relationship reduced daily COD reduction and biogas production compared with IM group. This study provides a new perspective for the selection of inoculation strategies for exogenous anaerobic digester sludge under different salinity, in order to realize energy conversion from salinity organic wastewater.

Malolactic fermentation of lactic acid bacteria isolated from southern Brazilian red wine.

The objective was to isolate lactic acid bacteria (LAB) from southern Brazil's wines and investigate their potential as starter cultures for malolactic fermentation (MLF) in Merlot (ME) and Cabernet Sauvignon (CS) wines through the fermentative capacity. The LAB were isolated from CS, ME, and Pinot Noir (PN) wines in the 2016 and 2017 harvests and evaluated for morphological (color and shape of the colonies), genetic, fermentative (increase in pH, acidity reduction, preservation of anthocyanins, decarboxylation of L-malic acid, yield of L-lactic acid, and content of reduced sugars), and sensory characteristics. Four strains were identified as Oenococcus oeni [CS(16)3B1, ME(16)1A1, ME(17)26, and PN(17)65], one as Lactiplantibacillus plantarum [PN(17)75], and one as Paucilactobacillus suebicus [CS(17)5]. Isolates were evaluated in the MLF and compared to a commercial strain (O. oeni), as well as a control (without inoculation and spontaneous MLF), and standard (without MLF). CS(16)3B1 and ME(17)26 isolates finished the MLF for CS and ME wines, respectively, after 35 days, similar to the commercial strain, and CS(17)5 and ME(16)1A1 isolates ended the MLF in 45 days. In the sensory analysis, ME wines with isolated strains received better scores for flavor and overall quality than the control. Compared to the commercial strain, CS(16)3B1 isolate obtained the highest scores for buttery flavor and taste persistence. CS(17)5 isolate received the higher scores for a fruity flavor and overall quality and the lowest for a buttery flavor. The native LAB displayed MLF potential, regardless of the year and grape species from which they were isolated.

Efficient bioremediation of indigo-dye contaminated textile wastewater using native microorganisms and combined bioaugmentation-biostimulation techniques.

In this work, the bioremediation of wastewater from the textile industry with indigo dye content was carried out using combined bioaugmentation, bioventilation, and biostimulation techniques. Initially, the inoculum was prepared by isolating the microorganisms from the textile wastewater in a 2 L bioreactor. Then, the respirometry technique was implemented to determine the affinity of the microorganisms and the substrate by measuring CO2 and allowed the formulation of an empirical mathematical model for the growth kinetics of the microorganism. Finally, the bioremediation was carried out in a 3 L bioreactor obtaining an indigo dye removal efficiency of 20.7 ± 1.2%, 24.0 ± 1.5%, and 29.7 ± 1.1% for equivalent wavelengths of 436 nm, 525 nm, and 620 nm. The chemical oxygen demand showed an average reduction of 88.9 ± 2.5%, going from 470.7 ± 15.6 to 52.3 ± 10.7 ppm after 30 days under constant agitation and aeration. A negative generalized exponential model was fitted to assess the affinity of the microorganism with the wastewater as a substrate by evaluating the production of CO2 during the bioremediation. Bioremediation techniques improve water discharge parameters compared to chemical treatments implemented in the industry, reducing the use of substances that can generate secondary pollution. Bioaugmentation, biostimulation, and bioventing of the textile wastewater in this study demonstrate the potential of these combined techniques to serve as an efficient alternative for indigo-contaminated wastewater in the textile industry.

Driving mechanisms for the adaptation and degradation of petroleum hydrocarbons by native microbiota from seas prone to oil spills.

Offshore waters have a high incidence of oil pollution, which poses an elevated risk of ecological damage. The microbial community composition and metabolic mechanisms influenced by petroleum hydrocarbons vary across different marine regions. However, research on metabolic strategies for in-situ petroleum degradation and pollution adaptation remains in its nascent stages. This study combines metagenomic techniques with gas chromatography-mass spectrometry (GC-MS) analysis. The data show that the genera Pseudoalteromonas, Hellea, Lentisphaera, and Polaribacter exhibit significant oil-degradation capacity, and that the exertion of their degradation capacity is correlated with nutrient and oil pollution stimuli. Furthermore, tmoA, badA, phdF, nahAc, and fadA were found to be the key genes involved in the degradation of benzene, polycyclic aromatic hydrocarbons, and their intermediates. Key genes (INSR, SLC2A1, and ORC1) regulate microbial adaptation to oil-contaminated seawater, activating oil degradation processes. This process enhances the biological activity of microbial communities and accounts for the geographical variation in their compositional structure. Our results enrich the gene pool for oil pollution adaptation and degradation and provide an application basis for optimizing bioremediation intervention strategies.

Reinforcement of reclaimed sand by stimulating native microorganisms for biomineralization.

The method of biological stimulation to reinforce soil has good environmental benefits. The optimization of stimulation solutions can not only improve soil reinforcement but also effectively reduce treatment costs. Response surface methodology was used to optimize a biostimulation solution to reinforce reclaimed sand by native microorganism-induced mineralization. First, response surface methodology was used to obtain the optimal stimulation solution. Then, the effect of the optimal stimulation solution in inducing mineralization to reinforce reclaimed sand was evaluated. Finally, the reinforcement mechanism was revealed by SEM, XRD, and microbial diversity analysis. The results showed that the urease activity of the sample optimized by response surface methodology was 1.17 times higher than that of the sample treated with the initial stimulation solution. The uniaxial compressive strength of samples treated with the optimal biostimulation solution and 1.0 M cementation solution over 15 cycles reached 3.94 MPa. The product of microbial mineralization was calcite, which was the main substance responsible for the improvement in the mechanical properties of the reclaimed sand. The concentration of the cementation solution not only affected the production of calcium carbonate but also affected the morphology of calcium carbonate crystals. After sample treatment with the stimulation solution, ureolytic microorganisms became the dominant bacteria in the sample. A comprehensive assessment of the reinforcement effect and cost revealed that using the optimal stimulation solution and 1.0 M cementation solution over 10 cycles was ideal for reinforcing reclaimed sand. Biostimulation is an effective method to reinforce reclaimed sand; however, the actual application effect requires further examination.

Reinforcement of Calcareous Sands by Stimulation of Native Microorganisms Induced Mineralization.

Calcareous sand is a special soil formed by the accumulation of carbonate fragments. Its compressibility is caused by a high void ratio and breakable particles. Because of its high carbonate content and weak cementation, its load-bearing capacity is limited. In this study, the optimal stimulation solution was obtained with response surface methodology. Then, the effect of reinforcing calcareous sand was analysed with unconfined compressive strength (UCS) tests, calcium carbonate content tests, microscopy and microbial community analyses. The components and concentrations of the optimal stimulation solution were as follows: sodium acetate (38.00 mM), ammonium chloride (124.24 mM), yeast extract (0.46 g/L), urea (333 mM), and nickel chloride (0.01 mM), and the pH was 8.75. After the calcareous sand was treated with the optimal stimulation scheme, the urease activity was 6.1891 mM urea/min, the calcium carbonate production was 8.40%, and the UCS was 770 kPa, which constituted increases of 71.41%, 35.40%, and 83.33%, respectively, compared with the initial scheme. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses showed that calcium carbonate crystals were formed between the particles of the calcareous sand after the reaction, and the calcium carbonate crystals were mainly calcite. Urease-producing microorganisms became the dominant species in calcareous sand after treatment. This study showed that biostimulation-induced mineralization is feasible for reinforcing calcareous sand.

An indigenous bacterium with enhanced performance of microbially-induced Ca-carbonate biomineralization under extreme alkaline conditions for concrete and soil-improvement industries.

The advantages of microbial induced carbonate mineralization for soil-stabilization and building-material industries are under extensive investigation. The pH is one of the influential parameters on the desired calcium carbonate mineralization due to the resulting textures of this mineral. Moreover, the decrease in microbial growth under the extreme alkaline environment compatible with the sustainability of concrete has been the bottleneck for an effective application of Microbial Induced Carbonate Precipitation (MICP) in the concrete industry. Microbial consortia have shown more robustness in their resistance to environmental fluctuations than pure cultures. In addition, microorganisms obtained from alkaline environments could facilitate their adaptation to extreme alkalinity. The aim of this study was to obtain urease producing bacteria (UPB) able to maintain a high MICP performance under extremely alkaline conditions compatible with concrete by adapting native microorganisms obtained from extreme environments. The growth performance, urease activity, strength of the generated biocement, and CaCO3 mineralogy were compared with the best-performer urease-producing bacteria (UPB), S. pasteurii DSMZ 33. The native bacteria presented a similar performance in growth and urease activity than S. pasteurii under extreme alkaline conditions (pH 12.5). However, the generated biocement of native Sporosarcina sp. achieved 461 % more unconfined compressive strength (UCS) and 120 % more CaCO3 content than the biocement generated by S. pasteurii DSMZ 33. The careful adaptation process performed in this study for native UPB and S. pasteurii DSMZ 33 is an interesting approach with promising and projectable results for future engineering and biotechnological applications. These results have important implications for the design of engineering solutions involving MICP. STATEMENT OF SIGNIFICANCE: A consolidated and strong biocement was generated by a native species obtained from extreme ecosystems in an effort of bioprospecting to enhance the performance of biotechnological solutions for geotechnical applications in the concrete and soil-improvement industries. Biocement generated by the native species was stronger than the generated by one of the best-described biocementation performers. This native species was able to actively growing and do perform microbial-induced-carbonate-mineralization under extreme alkalinity conditions after a careful laboratory adaptation process. The native species presented unique and differentiating traits that gave it a better adaptability and biocementation performance. The same occurs with a priceless microbial diversity inhabiting little explored and unprotected extreme ecosystems. Extreme environments house a fascinating biodiversity with potential value for ecosystem services.

Harnessing the Potential of Native Microbial Communities for Bioremediation of Oil Spills in the Iberian Peninsula NW Coast.

Oil spills are among the most catastrophic events to marine ecosystems and current remediation techniques are not suitable for ecological restoration. Bioremediation approaches can take advantage of the activity of microorganisms with biodegradation capacity thus helping to accelerate the recovery of contaminated environments. The use of native microorganisms can increase the bioremediation efficiency since they have higher potential to survive in the natural environment while preventing unpredictable ecological impacts associated with the introduction of non-native organisms. In order to know the geographical scale to which a native bioremediation consortium can be applied, we need to understand the spatial heterogeneity of the natural microbial communities with potential for hydrocarbon degradation. In the present study, we aim to describe the genetic diversity and the potential of native microbial communities to degrade petroleum hydrocarbons, at an early stage of bioremediation, along the NW Iberian Peninsula coast, an area particularly susceptible to oil spills. Seawater samples collected in 47 sites were exposed to crude oil for 2 weeks, in enrichment experiments. Seawater samples collected in situ, and samples collected after the enrichment with crude oil, were characterized for prokaryotic communities by using 16S rRNA gene amplicon sequencing and predictive functional profiling. Results showed a drastic decrease in richness and diversity of microbial communities after the enrichment with crude oil. Enriched microbial communities were mainly dominated by genera known to degrade hydrocarbons, namely Alcanivorax, Pseudomonas, Acinetobacter, Rhodococcus, Flavobacterium, Oleibacter, Marinobacter, and Thalassospira, without significant differences between geographic areas and locations. Predictive functional profiling of the enriched microbial consortia showed a high potential to degrade the aromatic compounds aminobenzoate, benzoate, chlorocyclohexane, chlorobenzene, ethylbenzene, naphthalene, polycyclic aromatic compounds, styrene, toluene, and xylene. Only a few genera contributed for more than 50% of this genetic potential for aromatic compounds degradation in the enriched communities, namely Alcanivorax, Thalassospira, and Pseudomonas spp. This work is a starting point for the future development of prototype consortia of hydrocarbon-degrading bacteria to mitigate oil spills in the Iberian NW coast.

Biorremediación de lodos contaminados con aceites lubricantes usados / Bioremediation of sludge contaminated with used lubricants

Los lodos contaminados con residuos de aceites lubricantes usados generan gran impacto ambiental negativo al no ser manejados adecuadamente. Se propuso la biorremediación para disminuir la concentración de dichos contaminantes. Los ensayos fueron realizados en las instalaciones de la planta de tratamiento de aguas residuales (PTAR) de Río Frío (Girón, Santander, Colombia), donde se evaluaron consorcios microbianos nativos, que posteriormente se adicionaron a las biopilas conformadas por lodos deshidratados provenientes del tratamiento primario de aguas residuales domésticas (usados como fuente de materia orgánica), lodos provenientes de lavaderos de carros y lodos de alcantarillado de la zona industrial de la ciudad de Bucaramanga (Colombia). Se aislaron, identificaron y conservaron cepas microbianas con capacidad degradadora de hidrocarburos totales de petróleo (TPH) como Pseudomonas spp., Acinetobacter spp, Enterobacter cloacae, Citrobacter spp., Bacillus brevis, Micrococcus spp y Nocardia spp. Se hizo una serie de pruebas piloto donde se inoculó cada montaje con un consorcio bacteriano a una concentración de 3x108 UFC/ml de bacterias y microorganismos fúngicos como Aspergillus spp., Fusarium spp., Trichoderma spp., a una concentración de 1x106 esporas/ml; se monitorearon parámetros de temperatura, pH, humedad y oxigenación. Se realizaron dos ensayos para verificar el comportamiento de dichos tratamientos; se analizó la variable continua TPH en ppm mediante el método de modelos mixtos lineares en bloques aleatorios completos, que revelaron diferencias significativas entre la biopila control y las biopilas bajo prueba; se obtuvieron porcentajes de remoción hasta de 94% de TPH en 120 días y 84% en 40 días, lo que reflejó un efecto positivo en la utilización de los consorcios de microorganismos bajo prueba en la descontaminación de lodos de alcantarillado industrial y lodos de lavaderos de carros.

The sludge contaminated with residues of used lubricating oils produce large negative environmental impact by not being handled properly. We proposed Biorremediation to decreasethe concentration of these polltants. The trials were conducted on the waste water treatment plant (WWTP) Río Frío (Girón, Santander, Colombia) ,we evaluate native microbial associations, and subsequently they were added to biopiles, made up of dried sludge the waste water treatment (source of organic mater) sludge from washing cars and sewage sludge from the industrial area of the city Bucaramanga (Colombia). Several pilot test were completed and we isolated, identified and retained microbial atrains with ability to degrading total petroleum hydrocarbons (TPH) such as Pseudomonas spp., Escherichia coli, Citrobacter spp., Bacillus brevis, Micrococcus spp., among others. We inoculated each pilot assembly with a bacterial concentration of 3x108 UFC/ml and fungal microorganisms like Aspergillus spp., Fusarium spp., Trichoderma spp. in a concentration of 1x106 Spores/ml. Parameters such as temperature, pH, humidity, oxygenation were monitoring frequently. Two trials were completed to verify the behabior and results of treatment, we analized continuously the concentration of TPH using linear mixed models approach in a randomized complete blocks, which revealed significant differences between control biopile (without microorganism consortia) and biopiles under test, obtaining removal percentages to 94% of TPH in 120 days, and 84% in 40 days, reflecting a positive effect on the use of consortia of microorganisms under test in the decontamination of domestic sewage sludge and industrial sludge and sludge the car wash.