Native Microbes Research Articles

Nutrient amendments enrich microbial hydrocarbon degradation metagenomic potential in freshwater coastal wetland microcosm experiments.

The impact of oil spills in a freshwater aquatic environment can pose dire social, economic, and ecological effects on the region. An oil spill in the Laurentian Great Lakes region has the potential to affect the drinking water of more than 30 million people. The light synthetic crude oil used in this experimental microcosm study is transported through an underground pipeline crossing the waterway between two Laurentian Great Lakes. This study collected metagenomic data (experiments in triplicate) and assessed the quantity of BTEX compounds, which connected microbial degradation function to gene potential. The resulting data documented the bioremediation capabilities of native microbes in a freshwater coastal wetland. This study also provided evidence for this region that bioremediation can be a viable remediation strategy instead of invasive physical methods.

Efficient astaxanthin production: Advanced strategies to improve microbial fermentation

AbstractAstaxanthin is a very valuable chemical with strong antioxidant effects, including anti‐cancer, anti‐inflammatory, eye protection, and other properties. The rapid development of synthetic biology has facilitated microbial astaxanthin production, offering environmental benefits, mild reaction conditions, and alignment with consumer demand for natural compounds. Accordingly, this review introduces the latest progress in the production of astaxanthin using different microorganisms including native microbes like Haematococcus pluvialis and Xanthophyllomyces dendrorhous, as well as engineered microbes like Yarrowia lipolytica and Escherichia coli. Methods for improving astaxanthin production through fermentation process regulation and metabolic engineering are reviewed and directions for future work are proposed.

Application of selenium isotopes to define selenium bioreduction in coal waste rock: Elk Valley, British Columbia

Anthropogenic sources of selenium (Se), including coal mining, can release Se to the environment and raise Se concentrations in receiving waters above drinking water and aquatic limits. Selenium bioreduction can be an important control to reduce dissolved selenate concentrations. This extensive study investigated the application of Se stable isotope ratios (δ82Se) of dissolved selenate to identify Se bioreduction in saturated and unsaturated mine rock piles (MRPs) located in the Elk Valley, Canada. The study included in situ and laboratory column experiments, where methanol was added to promote bioreduction. Results showed that selenate concentrations often are not reliable indicators of bioreduction. However, elevation of δ82Se relative to the selenate sources in all environments provided a robust indicator of widespread selenate bioreduction. Native microbes were shown to use both methanol and natural carbon sources as an electron donor for selenate bioreduction. Variability in the magnitude of apparent isotopic fractionation in column experiments was attributed to physical and microbiological heterogeneity, while variability in apparent isotopic fractionation from in situ experiments was attributed to the entrainment of small masses of background selenate into the experiment. Due to the uncertainty in apparent epsilon values, the extent of bioreduction can only be estimated with limited confidence. Despite uncertainties, however, the application of δ82Se is valuable in guiding the management of Se in mine environments.

Microbiome transfer from native to invasive species may increase invasion risk.

In a fast-changing world, understanding how organisms adapt to their environment is a pressing necessity. Research has focused on genetic adaptation, while our understanding of non-genetic modes is still in its infancy. The host-associated microbiome can be considered a non-genetic mode of adaptation, which can strongly influence an organism's ability to cope with its environment. However, the role of the microbiome in host ecological dynamics is largely unexplored, particularly in animal communities. Here, we discuss the following hypothesis: invasive species may rapidly adapt to local conditions by adopting beneficial microbes from similar co-occurring native species. This occurs when the invader's fitness is influenced by adaptation to local conditions that is facilitated by microbes acquired from native microbiomes. We present a minimal mathematical model to explore this hypothesis and show that a delayed acquisition of native microbes may explain the occurrence of an invasion lag. Overall, our results contribute to broadening the conceptualization of rapid adaptation via microbiome transfer and offer insights towards designing early intervention strategies for invasive species management.

How bioaugmentation for pesticide removal influences the microbial community in biologically active sand filters

Removing pesticides from biological drinking water filters is challenging due to the difficulty in activating pesticide-degrading bacteria within the filters. Bioaugmented bacteria can alter the filter's microbiome, affecting its performance either positively or negatively, depending on the bacteria used and their interaction with native microbes. We demonstrate that adding specific bacteria strains can effectively remove recalcitrant pesticides, like metaldehyde, yielding compliance to regulatory standards for an extended period. Our experiments revealed that the Sphingobium CMET-H strain was particularly effective, consistently reducing metaldehyde concentrations to levels within regulatory compliance, significantly outperforming Acinetobacter calcoaceticus E1. This success is attributed to the superior acclimation and distribution of the Sphingobium strain within the filter bed, facilitating more efficient interactions with and degradation of the pesticide, even when present at lower population densities compared to Acinetobacter calcoaceticus E1. Furthermore, our study demonstrates that the addition of pesticide-degrading strains significantly impacts the filter's microbiome at various depths, despite these strains making up less than 1% of the total microbial community. The sequence in which these bacteria are introduced influences the system's ability to degrade pesticides effectively. This research shows the potential of carefully selected and dosed bioaugmented bacteria to improve the pesticide removal capabilities of water filtration systems, while also highlighting the dynamics between bioaugmented and native microbial communities. Further investigation into optimizing bioaugmentation strategies is suggested to enhance the resilience and efficiency of drinking water treatment systems against pesticide contamination.

SIP-metagenomics reveals key drivers of rhizospheric Benzo[a]pyrene bioremediation via bioaugmentation with indigenous soil microbes

Rhizoremediation and bioaugmentation have proven effective in promoting benzo[a]pyrene (BaP) degradation in contaminated soils. However, the mechanism underlying bioaugmented rhizospheric BaP degradation with native microbes is poorly understood. In this study, an indigenous BaP degrader (Stenotrophomonas BaP-1) isolated from petroleum-contaminated soil was introduced into ryegrass rhizosphere to investigate the relationship between indigenous degraders and rhizospheric BaP degradation. Stable isotope probing and 16S rRNA gene amplicon sequencing subsequently revealed 15 BaP degraders, 8 of which were directly associated with BaP degradation including Bradyrhizobium and Streptomyces. Bioaugmentation with strain BaP-1 significantly enhanced rhizospheric BaP degradation and shaped the microbial community structure. A correlation of BaP degraders, BaP degradation efficiency, and functional genes identified active degraders and genes encoding polycyclic aromatic hydrocarbon-ring hydroxylating dioxygenase (PAH-RHD) genes as the primary drivers of rhizospheric BaP degradation. Furthermore, strain BaP-1 was shown to not only engage in BaP metabolism but also to increase the abundance of other BaP degraders and PAH-RHD genes, resulting in enhanced rhizospheric BaP degradation. Metagenomic and correlation analyses indicated a significant positive relationship between glyoxylate and dicarboxylate metabolism and BaP degradation, suggesting a role for these pathways in rhizospheric BaP biodegradation. By identifying BaP degraders and characterizing their metabolic characteristics within intricate microbial communities, our study offers valuable insights into the mechanisms of bioaugmented rhizoremediation with indigenous bacteria for high-molecular-weight PAHs in petroleum-contaminated soils.

Impact of Biotic and Abiotic Factors on Listeria monocytogenes, Salmonella enterica, and Enterohemorrhagic Escherichia coli in Agricultural Soil Extracts.

Outbreaks of Enterohemorrhagic Escherichia coli (EHEC), Salmonella enterica, and Listeria monocytogenes linked to fresh produce consumption pose significant food safety concerns. These pathogens can contaminate pre-harvest produce through various routes, including contaminated water. Soil physicochemical properties and flooding can influence pathogen survival in soils. We investigated survival of EHEC, S. enterica, and L. monocytogenes in soil extracts designed to represent soils with stagnant water. We hypothesized pathogen survival would be influenced by soil extract nutrient levels and the presence of native microbes. A chemical analysis revealed higher levels of total nitrogen, phosphorus, and carbon in high-nutrient soil extracts compared to low-nutrient extracts. Pathogen survival was enhanced in high-nutrient, sterile soil extracts, while the presence of native microbes reduced pathogen numbers. A microbiome analysis showed greater diversity in low-nutrient soil extracts, with distinct microbial compositions between extract types. Our findings highlight the importance of soil nutrient composition and microbial dynamics in influencing pathogen behavior. Given key soil parameters, a long short-term memory model (LSTM) effectively predicted pathogen survival. Integrating these factors can aid in developing predictive models for pathogen persistence in agricultural systems. Overall, our study contributes to understanding the complex interplay in agricultural ecosystems, facilitating informed decision-making for crop production and food safety enhancement.

Evaluation of biocementation of slope soil for erosion control with low-cost materials

In this study, biocementation of slope soil was performed using low-cost, commercially available materials to create a nutrient solution with native Cytobacillus hornekea. The high cost of laboratory-grade materials and microbes for biocementation is one of the main obstacles to its popularity. However, the cost of biocementation has been reduced significantly without reducing the strength when low-cost materials were used instead of laboratory-grade materials in this study. Direct shear test results and SEM also proved the suitability of the low-cost biocementation. Artificial rainfall with an intensity of 50–60 mm/h resulted in soil erosion of around 10% and 2% without and with biocementation, respectively. The amount of produced calcium carbonate was around 3.9% while using the low-cost materials with native microbes which is quite comparable with the laboratory-grade materials (3.4%).

Performance of salt‐bridge microbial fuel cell (SB‐MFC) with various microorganism cultures on the generation of electricity from tofu wastewater

A suitable wastewater treatment system is required due to the high organic compound content in tofu wastewater, which can harm the environment. Biological treatment methods are effective for treating tofu wastewater due to its characteristics. Microbial fuel cells (MFCs) represent one such biological treatment option, effectively removing organic contaminants while generating low‐power electricity through bioenergetic reactions. In MFCs, microorganisms are used as biocatalysts to degrade the organic compounds present in wastewater. This study aimed to assess the efficacy of Salt‐bridge microbial fuel cells (SB‐MFC) using various acclimatized microbe cultures for reducing organic compounds and generating energy from tofu wastewater. Tofu wastewater was sterilized prior to introduction into the reactor. Additional microbes, including the native microbe consortium from tofu wastewater, Escherichia coli, Saccharomycopsis fibuligera, and a mixed culture of E. coli and S. fibuligera, were then introduced as biocatalysts. Carbon electrodes were utilized as both the anode and cathode. The results indicate that the mixed culture of E. coli and S. fibuligera significantly reduced COD and BOD5 levels, with removal rates of 82.74% and 76.53%, respectively, after 48 h. Furthermore, the culture generated a voltage of 676 mV, a current of 2.53 mA, a power density of 428 mWatt/m2, and 4.789×10‐2 kWh of energy. This study contributes to the advancement of SB‐MFC by utilizing wastewater and a combination of bacteria and yeast as biocatalysts.

Root powder extract, phytochemical studies & preparation of herbal formulation tinospora cordifolia asava

Asava, a traditional formulation in Ayurveda, is renowned for its superior preservation and enhanced therapeutic efficacy. This phenomenon is largely attributed to the intricate process of fermentation facilitated by a consortium of microbes. Microbial activity not only extends the shelf-life of Asava but also transforms its constituent ingredients into potent therapeutics through biotransformation. The alcohol-aqueous milieu generated during fermentation not only preserves the formulation but also facilitates improved drug delivery within the body. This milieu, predominantly produced by microbial action, acts as a medium for the potentization of drugs, enhancing their bioavailability and efficacy. Moreover, the biotransformation mediated by native microbes leads to the synthesis of novel compounds with enhanced therapeutic properties, thereby elevating the overall efficacy of Asava. The preservative properties inherent in these formulations, coupled with microbial-mediated potentization, underscore the significance of microbial fermentation in augmenting the therapeutic potential of Asava in Ayurveda.

Dietary supplementation of rumen native microbes improves lactation performance and feed efficiency in dairy cows

Objectives were to determine the effects of 2 dietary microbial additives supplemented to diets of Holstein cows on productive performance and feed efficiency. One-hundred and 17 Holstein cows were enrolled at 61 d (31 to 87 d) postpartum in a randomized complete block design experiment. Cows were blocked by parity group, as nulliparous or multiparous cows and, within parity, by pre-treatment energy-corrected milk yield. Within block, cows were randomly assigned to one of 3 treatments administered as top-dress for 140 d. Treatments consisted of either 100 g of corn meal containing no microbial additive (CON; 15 primiparous and 25 multiparous), 100 g of corn meal containing 5 g of a mixture of Clostridium beijerinckii and Pichia kudriavzevii (G1; 4 × 107 cfu of C. beijerinckii and 1 × 109 cfu of P. kudriavzevii; 14 primiparous and 24 multiparous), or 100 g of corn meal containing 5 g of a mixture of C. beijerinckii, P. kudriavzevii, Butyrivibrio fibrisolvens, and Ruminococcus bovis (G2; 4 × 107 cfu of C. beijerinckii, 1 × 109 cfu of P. kudriavzevii, 1 × 108 cfu of B. fibrisolvens, and 1 × 108 cfu of R. bovis; 15 primiparous and 24 multiparous). Intake of DM, milk yield, and BW were measured daily, whereas milk composition was analyzed at each milking 2 d a week, and body condition was scored twice weekly. Milk samples were collected on d 60 and 62 in the experiment and analyzed for individual fatty acids. The data were analyzed with mixed-effects models with orthogonal contrast to determine the impact of microbial additive (MA; CON vs. 1/2 G1 + 1/2 G2) and type of microbial additive (TMA; G1 vs. G2). Results are described in sequence as CON, G1, and G2. Intake of DM (22.2 vs. 22.4 vs. 22.4 kg/d), BW (685 vs. 685 vs. 685 kg) and the daily BW change (0.40 vs. 0.39 vs. 0.39 kg/d) did not differ among treatments; however, feeding MA tended to increase BCS (3.28 vs. 3.33 vs. 3.36). Supplementing MA increased yields of milk (39.9 vs. 41.3 vs. 41.5 kg/d), ECM (37.9 vs. 39.3 vs. 39.9 kg/d), fat (1.31 vs. 1.37 vs. 1.40 kg/d), total solids (4.59 vs. 4.75 vs. 4.79 kg/d), and ECM per kg of DMI (1.72 vs. 1.76 vs. 1.80 kg/kg). Furthermore, cows fed MA increased yields of pre-formed fatty acids in milk fat (>16C; 435 vs. 463 vs. 488 g/d), particularly unsaturated fatty acids (367 vs. 387 vs. 410 g/d), such as linoleic (C18:2 cis-9, cis-12; 30.9 vs. 33.5 vs. 35.4 g/d) and α-linolenic acids (C18:3 cis-9, cis-12, cis-15; 2.46 vs. 2.68 vs. 2.82 g/d) on d 60 and 62 in the experiment. Collectively, supplementing G1 and G2 improved productive performance of cows with no differences between the 2 MA.

Role of Genetically Modified Microorganisms for Effective Elimination of Heavy Metals.

Heavy metals are lethal and hazardous pollutants for the ecosystem owing to their virtues including acute toxicity, prolonged persistence, and bioaccumulation. These contaminants are not only a threat to aquatic/terrestrial biota but also pose serious health issues to humans. Natural and anthropologic processes consistently upsurge heavy metal concentration beyond acceptable limits and mobilization and hence disturb biogeochemical cycles and the food chain, although several conventional strategies including adsorption, chemical precipitation, ion exchange, and membrane separation methods are being employed for the removal of these lethal heavy metals from the ecosystem but failed due to lower efficiency rates and high application charges. The current scenario highly demands advanced biosorption or bioaccumulation processes that slow down heavy metal mobilization within the acceptable limit in the ecosystem. Genetically modified microorganisms (GMMs) with desired features are developed through interdisciplinary participation of genomics, molecular microbiology, and bioinformatics that have more potential to bioremediate heavy metals than the native microbes from polluted ecosystems. The study focuses on different sources of heavy metals, their impact on the ecosystem, and the bioremediation of toxic heavy metals via GMMs.

Can Phytoremediation-Induced Changes in the Microbiome Improve Saline/Sodic Soil and Plant Health?

Increasing soil salinity and/or sodicity is an expanding problem in the Northern Great Plains (NGP) of North America. This study investigated the impact of phytoremediation on the soil microbiome and if changes, in turn, had positive or negative effects on plant establishment. Amplicon sequencing and gas chromatograph/mass spectrometer analysis compared root metabolites and microbial composition of bulk vs. rhizosphere soils between two soil types (productive and saline/sodic). Beta-diversity analysis indicated that bacterial and fungal communities from both the bulk and rhizosphere soils from each soil type clustered separately, indicating dissimilar microbial composition. Plant species also influenced both root-associated bacterial and fungal communities with separate clustering of operational taxonomic units (OTUs) identified. Canonical correlation analysis (CCA) found a clear association between specific soil characteristics and soil types. Bacterial and fungal OTUs from productive soil were correlated with greater %Ca Sat, %H Sat, and potassium (ppm), especially for OTUs differentially enriched in productive soil. Both bacterial and fungal OTUs from saline/sodic soil are associated with increased Ca (ppm), soil pH, %Na Sat and CEC. Metabolite analysis showed that kochia (Bassia scoparia) roots from the saline/sodic soil had a 4.4-fold decrease in pantothenate accumulation (p = 0.004). Moreover, two endophytic bacterial isolates, a Bacillus spp. and a previously uncultured halophile, isolated from creeping foxtail (Alopecurus arundinaceus) grown in saline/sodic soil and used as buckwheat (Fagopyrum esculentum) seed inoculants, significantly increased seed germination by >30% and vigor index by 0.2 under osmotic stress (0.2 M NaCl) (p < 0.05). This study revealed the importance of soil, root-associated, and endophytic microbiomes. Using native microbes as seed inoculants may help in establishment and growth of species used for phytoremediation of saline/sodic soil.

Microbial communities drive flux of acid orange 7 and crystal violet dyes in water-sediment system

Unchecked dye effluent discharge poses escalating environmental and economic concerns, especially in developing nations. While dyes are well-recognized water pollutants, the mechanisms of their environmental spread are least understood. Therefore, the present study examines the partitioning of Acid Orange 7 (AO7) and Crystal Violet (CV) dyes using water-sediment microcosms and reports that native microbes significantly affect AO7 decolorization and transfer. Both dyes transition from infused to pristine matrices, reaching equilibrium in a fortnight. While microbes influence CV partitioning, their role in decolorization is minimal, emphasizing their varied impact on the environmental fate of dyes. Metagenomic analyses reveal contrasting microbial composition between control and AO7-infused samples. Control water samples displayed a dominance of Proteobacteria (62%), Firmicutes (24%), and Bacteroidetes (9%). However, AO7 exposure led to Proteobacteria reducing to 57% and Bacteroidetes to 3%, with Firmicutes increasing to 34%. Sediment samples, primarily comprising Firmicutes (47%) and Proteobacteria (39%), shifted post-AO7 exposure: Proteobacteria increased to 53%, and Firmicutes dropped to 38%. At the genus level, water samples dominated by Niveispirillum (34%) declined after AO7 exposure, while Bacillus and Pseudomonas increased. Notably, Serratia and Sphingomonas, known for azo dye degradation, rose post-exposure, hinting at their role in AO7 decolorization. Conversely, sediment samples showed a decrease in the growth of Bacillus and an increase in that of Pseudomonas and Serratia. These findings emphasize the significant role of microbial communities in determining the environmental fate of dyes, providing insights on its environmental implications and management.

Inoculating native microorganisms improved soil function and altered the microbial composition of a degraded soil

Restoration managers inoculate microorganisms to enhance soil function and improve restoration success, but the efficacy of these inoculations in real‐world conditions is still unclear. We conducted a field experiment to test whether applying extruded seed pellets inoculated with native microbes affected soil properties related to ecosystem function in severely degraded mine soil. We found that inoculating with bacteria did not affect soil carbon, metabolic quotient (a measure of microbial stress), or basal respiration, but increased soil nitrogen by 75%, substrate‐induced respiration by 147% and reduced carbon‐to‐nitrogen ratio by 44% compared to the control. This suggests that the bacteria inoculant contained free‐living N fixers that increased the soil N content. Thus, inoculating with bacteria could supplement nitrogen fertilizers in degraded soils during soil restoration. However, we found that inoculating with a mix of bacteria and cyanobacteria did not affect any of the soil properties. This finding is counter to results in laboratory studies, suggesting that field tests are critical for understanding real‐world outcomes of microbial inoculation. Finally, we found that soil microbial composition was changed by the inoculation with a mix of bacteria and cyanobacteria. None of the treatments significantly changed the diversity of soil microbial communities. Our data suggest that microbial inoculation could improve some aspects of ecosystem function and thus provide beneficial effects that might facilitate restoration of degraded sites.

Assessing soil bacterial community response to organophosphate pesticides in agricultural field of Yogyakarta, Java, Indonesia

Soil contamination by pesticides is one of the world’s most pressing environmental issues. The widespread use of Organophosphate pesticides (OPPs) in agriculture has led to biological diversity changes. The indigenous bacterial community played significant roles in the remediation of soil contaminated with OPPs. This study examines the overall bacterial community composition of three agricultural fields in Yogyakarta, Java, Indonesia, that were exposed to OPPs. The agricultural field was divided into zones near the beach, residential, and mountainous. Sequencing 16S rRNA amplicon fragments used to analyze the soil bacterial community. It was discovered that Proteobacteria, Actinobacteria, and Firmicutes comprised the majority of the bacterial community. In addition, the samples contain a high relative abundance of Bacillus, Bradyrhizobium, Chryseobacterium, Cystobacter, Microvirga, and Burkholderia. The high alpha diversity indexes suggest that the agricultural soil microbiome provides important ecological services and may harbor a wide variety of bacteria and genes with biotechnological applications. The physicochemical soil characteristics are also correlated with the bacterial community structure. The findings can be used to develop bioremediation strategies that employ native microbes to clean and restore agricultural soil contaminated with OPPs.

A comprehensive review of arsenic contamination in India with an emphasis on its detection through biosensors and bioremediation from the aqueous system

AbstractIn India, where millions of people use groundwater for drinking, arsenic pollution in groundwater is a major environmental and public health issue. The review begins by analyzing the sources and causes of groundwater arsenic pollution, including natural geological processes and anthropogenic activities like mining and industrial discharge. It emphasizes India's most arsenic‐contaminated regions and the health risks of long‐term exposure. The review's second section focuses on the use of biosensors to find arsenic in groundwater. A potential method is provided by biosensors because of their great sensitivity, selectivity, and quick response. The benefits and drawbacks of several types of biosensors, including optical, electrochemical, and microbiological biosensors, are discussed. The utilization of nanomaterials, biomolecular recognition components, and miniature devices are only a few of the most recent developments in biosensor technology for arsenic detection that are studied. The review's last section discusses methods for bio‐remediating aqueous systems that have been contaminated with arsenic. Various bioremediation techniques are covered in detail, including microbial degradation, phytoremediation, and biosorption. The promise for removing arsenic using native microbes and plant species is highlighted, along with the difficulties of widespread application and long‐term sustainability. Overall, focusing on the detection of arsenic using biosensors and investigating bioremediation techniques, this review offers a thorough grasp of the arsenic poisoning in groundwater in India. In order to combat arsenic contamination and protect the health and wellbeing of the impacted populations in India, it emphasizes the need for interdisciplinary research and collaboration among scientists, engineers, policymakers, and local communities.

Influence of connatural factors in shaping vaginal microflora and ensuring its health.

Vaginal canal (VC) is exposed to the external environment affected by habitual factors like hygiene and sexual behaviour as well as physiological factors like puberty, menstrual cycle, pregnancy, child birth and menopause. Healthy VC harbours beneficial microflora supported by vaginal epithelium and cervical fluid. Connatural antimicrobial peptide (AMPs) of female reproductive tract (FRT) conjunctly with these beneficial microbes provide protection from a large number of infectious diseases. Such infections may either be caused by native microbes of the VC or transitory microbes like bacteria or virus which are not a part of VC microflora. This review highlight's the role of hormones, enzymes, innate immunological factors, epithelial cells and vaginal mucus that support beneficial microbes over infectious ones thus, helping to maintain homeostasis in VC and further protect the FRT. We also discuss the prospective use of vaginal probiotics and AMPs against pathogens which can serve as a potential cure for vaginal infections.

Simulating compatible solute biosynthesis using a metabolic flux model of the biomining acidophile, Acidithiobacillus ferrooxidans ATCC 23270

Halotolerant, acidophilic, bioleaching microorganisms are crucial to biomining operations that utilize saline water. Compatible solutes play an important role in the adaptation of these microorganisms to saline environments. Acidithiobacillus ferrooxidans ATCC 23270, an iron- and sulfur-oxidizing acidophilic bacterium, synthesizes trehalose as its native compatible solute but is still sensitive to salinity. Recently, halotolerant bioleaching bacteria were found to use ectoine as their key compatible solute. Previously, bioleaching bacteria were recalcitrant to genetic manipulation; however, recent advancements in genetic tools and techniques allow successful genetic modification of A. ferrooxidans ATCC 23270. Therefore, this study aimed to test, in silico, the effect of native and synthetic compatible solute biosynthesis by A. ferrooxidans ATCC 23270 on its growth and metabolism. Metabolic network flux modelling was used to provide a computational framework for the prediction of metabolic fluxes during production of native and synthetic compatible solutes by A. ferrooxidans ATCC 23270, in silico. Complete pathways for trehalose biosynthesis by the bacterium are proposed and captured in the updated metabolic model including a newly discovered UDP-dependent trehalose synthesis pathway. Finally, the effect of nitrogen sources on compatible solute production was simulated and showed that using nitrogen gas as the sole nitrogen source enables the ectoine-producing ‘engineered’ microbe to oxidize up to 20% more ferrous iron in comparison to the native microbe that only produces trehalose. Therefore, the predictive outcomes of the model have the potential to guide the design and optimization of a halotolerant strain of A. ferrooxidans ATCC 23270 for saline bioleaching operations.

Study Investigates Conversion of Biomethane From CO2 and Biohydrogen

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper IPTC 22744, “Accelerated Methanogenesis for the Conversion of Biomethane From Carbon Dioxide and Biohydrogen at Hyperthermophilic Conditions,” by Ivy C.C. Hsia, Petronas, and Mohd F.A. Wahab and Nur K.A. Jalil, Universiti Teknologi Malaysia, et al. The paper has not been peer reviewed. Copyright 2023 International Petroleum Technology Conference. Reproduced by permission. _ Methanogenesis is the conversion of CO2 to methane (CH4) using microbes. In the context of CO2 usage, the process of methanogenesis using native microbes from a particular reservoir can be a very slow process without any external intervention. The study detailed in this complete paper investigates the use of agriculture byproducts such as palm oil mill effluent (POME) as substrates, along with potential microbial isolates that can produce biohydrogen at high temperatures. The authors write that stimulation of microbes using POME as substrate with hydrogen (H2)/CO2 supplementation is important in accelerating the rate and yield of CH4 production. Introduction The authors write that a population of microbes isolated from sludge of agriculture wastes, when given proper conditions and nutrients, was able to accelerate the rate of methanogenesis. POME is an agricultural byproduct from which a huge microbial community can be manipulated for methanogenesis, specifically for hydrogen production. This study incorporates the process of dark fermentation, using POME to generate hydrogen required to convert CO2 to CH4 in a syntrophic reaction at hyperthermophilic temperatures. Accounting for both the high reservoir temperatures (above 100°C) common to Malaysia and the temperature-tolerance limit of most microorganisms in general, the authors selected 70°C as the temperature to be studied. They write that, as their team studied a range of different temperatures, anaerobic microbes showed no production of biohydrogen and CH4 above 70°C.