Search Results (295)

Background: Prebiotics are selectively used by host microorganisms to promote health. Because effective prebiotic doses (1.5–30 g/day) often require inconvenient delivery formats, this study aims to explore whether capsule-compatible doses of galacto-oligosaccharides (GOS) can effectively modulate the gut microbiome. Methods: The impact of Bimuno^® GOS (Reading, UK) at 0.5, 0.75, 1.83, and 3.65 g on the adult gut microbiome was assessed using the ex vivo SIFR^® technology (n = 8), a clinically validated, bioreactor-based technology. Results: The GOS were rapidly fermented and significantly increased beneficial Bifidobacterium species (B. adolescentis, B. bifidum, and B. longum), even at the lowest tested dose. In doing so, GOS strongly promoted SCFA production, particularly acetate (significant from 0.5 g) and butyrate (significant from 0.75 g). Gas production only mildly increased, likely as Bifidobacterium species do not produce gases. Based on the ability of the SIFR^® technology to cultivate strictly anaerobic, hard-to-culture gut microbes, unlike in past in vitro studies, we elucidated that GOS also enriched specific Lachnospiraceae species. Besides Anaerobutyricum hallii, this included Bariatricus comes, Blautia species (B. massiliensis, Blautia_A, B. faecis), Oliverpabstia intestinalis, Mediterraneibacter faecis, and Fusicatenibacter species. Finally, GOS also promoted propionate (significant from 0.75 g), linked to increases in Phocaeicola vulgatus. Conclusions: GOS displayed prebiotic potential at capsule-compatible doses, offering greater flexibility in nutritional product formulation and consumer convenience. Notably, the strong response at the lowest dose suggests effective microbiome modulation at lower levels than previously expected. Full article

The presence of recalcitrant organic compounds in oilfield-produced-water poses significant challenges for conventional biological treatment technologies. In this study, an Fe³⁺-augmented composite bioreactor was developed to enhance the multi-pollutant removal performance and to elucidate the associated microbial community dynamics. The Fe³⁺-augmented system achieved efficient removal of oil (99.18 ± 0.91%), suspended solids (65.81 ± 17.55%), chemical oxygen demand (48.63 ± 15.15%), and polymers (57.72 ± 14.87%). The anaerobic compartment served as the core biotreatment unit, playing a pivotal role in microbial pollutant degradation. High-throughput sequencing indicated that Fe³⁺ supplementation strengthened syntrophic interactions between iron-reducing bacteria (Trichococcus and Bacillus) and methanogenic archaea (Methanobacterium and Methanomethylovorans), thereby facilitating the biodegradation of long-chain hydrocarbons (e.g., eicosane and nonadecane). Further metabolic function analysis identified long-chain-fatty-acid CoA ligase (EC 6.2.1.3) as a key enzyme mediating the interplay between hydrocarbon degradation and nitrogen cycling. This study elucidated the ecological mechanisms governing Fe³⁺-mediated multi-pollutant removal in a composite bioreactor and highlighted the potential of this approach for efficient, sustainable, and adaptable management of produced water in the petroleum industry. Full article

Industrial wastewater management remains a critical barrier to achieving Sustainable Development Goal 6 (SDG 6) in many developing countries, where regulatory frameworks exist but affordable and scalable treatment solutions are lacking. In Pakistan, the textile sector is a leading polluter, with untreated effluents routinely discharged into rivers and agricultural lands despite stringent National Environmental Quality Standards (NEQS). This study presents a pilot-scale case from Faisalabad’s Khurrianwala industrial zone, where a decentralized, nature-based bioreactor was piloted to bridge the gap between policy and practice. The system integrates four treatment stages—anaerobic digestion (AD), floating treatment wetland (FTW), constructed wetland (CW), and sand filtration (SF)—and was further intensified via nutrient amendment, aeration, and bioaugmentation with three locally isolated bacterial strains (Acinetobacter junii NT-15, Pseudomonas indoloxydans NT-38, and Rhodococcus sp. NT-39). The fully intensified configuration achieved substantial reductions in total dissolved solids (TDS) (46%), total suspended solids (TSS) (51%), chemical oxygen demand (COD) (91%), biochemical oxygen demand (BOD) (94%), nutrients, nitrogen (N), and phosphorus (P) (86%), sulfate (26%), and chloride (41%). It also removed 95% iron (Fe), 87% cadmium (Cd), 57% lead (Pb), and 50% copper (Cu) from the effluent. The bacterial inoculants persist in the system and colonize the plant roots, contributing to stable bioremediation. The treated effluent met the national environmental quality standards (NEQS) discharge limits, confirming the system’s regulatory and ecological viability. This case study demonstrates how nature-based systems, when scientifically intensified, can deliver high-performance wastewater treatment in industrial zones with limited infrastructure—offering a replicable model for sustainable, SDG-aligned pollution control in the Global South. Full article

In view of the growing global need for sustainable protein sources, this study explores the utilization of short-chain fatty acids into single-cell protein using the non-conventional yeast Cyberlindnera jadinii. Short-chain fatty acids can be sustainably produced via anaerobic digestion of organic waste, presenting a promising fermentation substrate for a circular bioeconomy. Cyberlindnera jadinii is demonstrated to be capable of growing on acetate, propionate and butyrate as both a carbon and energy source without strong inhibition. Bioprocess development was conducted in stirred tank bioreactors, where a fed-batch pH-stat bioprocess led to improved efficiency without substrate inhibition. The highest titer of 31.3 ± 1.0 g/L, rate of 0.67 ± 0.02 g/L/h and yield of 0.36 ± 0.01 g/g was achieved with propionate. The resulting biomass contained 41.3% crude protein, and 17.3% crude lipids with 81% unsaturated fatty acids. In contrast to acetate and butyrate, propionate as a substrate led to accumulation of 37% odd-chain fatty acids with titer, rate and yield of 1.74 ± 0.06 g/L, 0.037 ± 0.001 g/L/h and 0.020 ± 0.001 g/g. These findings confirm that short-chain fatty acids are viable fermentation substrates not only for single-cell protein, but also unsaturated and odd-chain fatty acid production with Cyberlindnera jadinii. Full article

Biological wastewater treatment systems exhibit a wide range of operating conditions and influent substrate types. Artificial intelligence methods, particularly artificial neural networks (ANNs), are increasingly being employed to manage this complexity. This study uses ANN modeling to identify the key operational parameters that influence the efficacy of anaerobic sulfide oxidation (ASO) biotechnology, which simultaneously treats nitrite and sulfide. The ANN model was further analyzed through SHAP analysis to determine the key operational parameters. The dataset used in this study was derived from previously published operational data of ASO reactors. The results revealed that the sulfide-to-nitrite (S:N) ratio and hydraulic retention time (HRT) had the greatest impact on sulfide removal. In contrast, influent sulfide and nitrite concentrations had no effect on the prediction of effluent pH. While other parameters had a positive effect, HRT had a slight negative impact on effluent pH, with the S:N ratio having the most effect. Furthermore, while other factors contributed to sulfate generation, sulfide influent and HRT had a significant impact. Predicting nitrite-nitrogen (NO₂⁻-N) removal is mostly dependent on the S:N ratio and influent pH. To enhance ASO reactor performance for sulfide and nitrite removal, it is recommended to prioritize the optimization of the S:N ratio and HRT, as these parameters have the greatest impact on key treatment outcomes, including sulfide and NO₂⁻-N removal and sulfate formation. Full article

This study investigated the dynamics and composition of microbial communities within the bioreactors of a two-stage anaerobic system employed for the bioconversion of corn steep liquor, a food processing byproduct, into hydrogen and methane. The high organic matter content of such wastes positions them as valuable substrates for biotechnological applications. The two-stage anaerobic digestion (AD) process was compartmentalized into a hydrogen-producing bioreactor (3 dm³) and a methane-producing bioreactor (15 dm³), each harboring distinct microbial consortia. The system yielded a maximal hydrogen production of 1.02 L/day and a peak methane production of 24.1 L/day with substrate corn steep liquor and cattle manure in a ratio 1:1. Microbial consortia were recognized as critical drivers of AD performance and biofuel yield. This research demonstrated the efficacy of a two-stage approach, segregating the hydrogenic (hydrolysis and acidogenesis) and methanogenic (acetogenesis and methanogenesis) phases, for optimized energy recovery from the co-digestion of corn steep liquor and cattle manure under controlled conditions. Metagenomic sequencing and a subsequent bioinformatics analysis were utilized to characterize the microbial diversity within each bioreactors. These findings contribute to a deeper understanding of the microbial ecology of AD and hold the potential for broader applications in waste-to-energy bioconversion. Full article

The European Union views biogas production from landfills as a crucial element in achieving decarbonization goals by 2050. Biogas is primarily composed of methane (CH₄) and carbon dioxide (CO₂), produced through the anaerobic digestion of various residual materials. This study aimed to investigate CH₄ and CO₂ concentrations from municipal solid waste in biogas capture wells in a landfill in Romania between 2023 and 2024. A peak in CH₄ concentrations occurred in the fall of 2024 (P4 well), while the highest CO₂ content was recorded in the summer of 2023 (P3 well). The Aermod View software platform (version 11.2.0) was employed to model the dispersion of pollutants in the surrounding air. A worst-case scenario was applied to estimate the highest ground-level pollutant concentrations. The highest recorded CH₄ concentration was 90.1 mg/m³, while CO₂ reached 249 mg/m³ within the landfill. The highest CH₄ concentrations were found in the southern part of the site, less than 1 km from the landfill, while CO₂ was highest in the northern area. In conclusion, municipal solid waste landfills behave like unpredictable bioreactors, and without proper management and oversight, they can pose significant risks. An integrated system that combines prevention, reuse, and correct disposal is critical to minimizing these negative effects. Full article

The development of food waste anaerobic digestion (AD) is a contemporary research topic addressed in the scientific community to meet the requirements of food waste valorization and proper substrate configuration for an efficient AD process. In this study, multiple AD experiments were performed on food waste together with industrial inoculum using laboratory-scale bioreactors. Food waste consisted mainly of fruits and vegetables (80.9%) and boiled rice (19.1%). The effect of operating temperature (33 °C, 37 °C, 41 °C, 45 °C) and the ratio between food waste mixture and inoculum-FIR (1:1, 3:2 and 2:1, w/w) on the production and composition of biogas, and the conversion yield for CH₄ and organic carbon, were investigated. The best results were obtained at an FIR of 2:1 and a temperature of 37 °C, with a total biogas production of 468.59 NL h⁻¹ kg⁻¹_VSadded (51% v/v CH₄ conc.) and a conversion yield of 36.42% for CH₄. A modified Gompertz model was applied on the accumulated CH₄ and biogas to evaluate the process performance. The model parameters were investigated in conjunction with the physico-chemical characteristics of the substrate, inoculum taxonomic profile, pH measurements, and TG-DTA analysis. The conducted analyses emphasized the susceptibility of the selected substrate towards easy degradation and improved biotransformation reactions when temperature and FIR were increased. Full article

Leachate management remains a major environmental challenge, especially in rapidly urbanizing cities of developing countries. Traditionally considered toxic and useless, it is a sustainable organic resource with the potential for high-value biochemical production through bioprocessing. This study investigated the characteristics of fresh leachates from three solid waste transfer stations (SWTS) in the Abidjan district, Côte d’Ivoire, and assessed their potential as substrates for medium-chain fatty acid (MCFA) production via microbial chain elongation. The MCFA synthesis was carried out in anaerobic bioreactors operated under methanogenesis inhibition conditions. The leachates from Bingerville, Abobo-Dokui, and Yopougon exhibited acidic and high organic content, particularly volatile fatty acids (VFAs), key precursors for MCFA synthesis. High concentrations of microbial communities associated with chain elongation were observed, including Clostridium (sulphite-reducing), Lactobacillus, Bacillus, and Pseudomonas (greater than 5 log10 CFU/mL). MCFA production ranged from 5 to 10 g/L, mainly C6, C7, and C8, with compositional variation depending on the SWTS. Notably, leachates from higher-income areas demonstrated higher MCFA productivity compared to those from lower-income areas. These findings highlight the potential of fresh SWTS leachates in the Abidjan district for sustainable MCFA production, paving the way for industrial applications. Full article

This study investigates membrane fouling control in a submerged anaerobic ceramic membrane bioreactor (AnCMBR) treating high-strength food wastewater (chemical oxygen demand (COD): 10–30 g/L). A hybrid strategy combining mechanical cleaning via a moving rubber blade (MRB) (termed anaerobic ceramic blade MBR (AnCBMBR)) with intermittent salt-assisted backwash (SAB) was tested to manage transmembrane pressure (TMP) and sustain treatment performance. During more than 300 days of field operation, MRB alone maintained stable TMP below 0.15 kg_f/cm² without backwashing, achieving more than 90% COD removal at a very short hydraulic retention time (HRT) of 1–2 days. Introducing intermittent SAB further stabilized operations and enhanced total phosphorus (T-P) removal by facilitating struvite formation through the interaction of MgCl₂ and phosphorus in the reactor. The AnCBMBR system demonstrated reliable, long-term fouling control and treatment efficiency, even under high organic loads, proving its viability for small-scale facilities managing concentrated food wastewater. This study advances practical strategies for sustainable anaerobic MBR operation under challenging industrial conditions. Full article

This study introduces a novel mathematical model characterizing the anaerobic co-digestion of wheat straw and waste algal biomass for hydrogen and methane production, implemented in a two-stage bioreactor system. Co-digestion can be a tool to increase biogas production utilizing difficult-to-digest organic waste by introducing easily degradable substrates. Two continuous operational regimes, with organic loading rates of 50 g/L and 33 g/L, were employed to generate the experimental datasets for model parameterization and validation, respectively. Parameter identification was achieved through dynamic experimentation, utilizing three distinct optimization algorithms: the deterministic active-set method (A-S) and the metaheuristics–genetic algorithm (GA), coyote optimization algorithm (COA), and marine predator algorithm (MPA). We assessed the predictive capability of the developed mathematical models using an independent dataset. The models demonstrated good agreement with the experimental data across all measured process variables. Notably, the MPA exhibited superior data fitting accuracy, as quantitatively confirmed by the objective function value, compared to GA, COA, and the A-S algorithm. Full article

Background: Nowadays, the microbial degradation of cellulose represents a new perspective for reducing cellulose waste from industry and households and at the same time obtaining energy sources. Methods: We isolated and enriched two aerobic (at 37 °C and 50 °C) and one anaerobic microbial consortium from an anaerobic bioreactor for biogas production by continuous subculturing on peptone cellulose solution (PCS) medium supplemented with 0.3% treated or untreated Whatman filter paper under static conditions. Samples were taken every 7 days until day 21 to determine the percentage of cellulose biodegradation. We determined the antimicrobial resistance of aerobic and anaerobic consortia and some single colonies by disc diffusion method, against 42 clinically applied antibiotics. PCR analyses were performed to search for the presence of eight genes for cellulolytic activity and nine genes for antibiotic resistance. By metagenomics analysis, the bacterial and fungal genus distributions in the studied populations were determined. Results: Aerobes cultured at 50 °C degraded cellulose to the greatest extent (47%), followed by anaerobes (24–38%) and aerobes (8%) cultured at 37 °C. The bacterial sequence analysis showed that the dominant phyla are Bacillota and Bacteroidetes and genera—Paraclostridium, Defluvitalea, Anaerobacillus, Acetivibrio, Lysinibacillus, Paenibacillus, Romboutsia, Terrisporobacter, Clostridium, Sporanaerobacter, Lentimicrobium, etc. in a different ratio depending on the cultivation conditions and the stage of the process. Some of these representatives are cellulolytic and hemicellulolytic microorganisms. We performed lyophilization and proved that it is suitable for long-term storage of the most active consortium, which degrades even after the 10th re-inoculation for a period of one year. We proved the presence of ssrA, ssrA BS and blaTEM genes. Conclusions: Our findings demonstrated the potential utility of the microbial consortium of anaerobes in the degradation of waste lignocellulose biomass. Full article

Biological reduction of sulphates has gradually replaced unit chemical processes for the treatment of acid mine drainage (AMD), which exerts a significant environmental impact due to its elevated acidity and high concentrations of heavy metals. Bioremediation is optimally suited for the treatment of AMD because it is cost-effective and efficient. Anaerobic bioremediation employing sulphate-reducing bacteria (SRB) presents a promising solution by facilitating the reduction of sulphate to sulphide. The formed can precipitate and immobilise heavy metals, assisting them in their removal from contaminated wastewater. This paper examines the current status of SRB-based bioremediation, with an emphasis on recent advances in microbial processes, reactor design, and AMD treatment efficiencies. Reviewed studies showed that SRB-based bioreactors can achieve up to 93.97% of sulphate reduction, with metal recovery rates of 95% for nickel, 98% for iron and copper, and 99% for zinc under optimised conditions. Furthermore, bioreactors that used glycerol and ethanol as a carbon source improved the efficiency of sulphate reduction, achieving a pH neutralisation from 2.8 to 7.5 within 14 days of hydraulic retention time. Despite the promising results achieved so far, several challenges remain. These include the need for optimal environmental conditions, the management of toxic hydrogen sulphide production, and the economic feasibility of large-scale applications. Future directions are proposed to address these challenges, focusing on the genetic engineering of SRB, integration with other treatment technologies, and the development of cost-effective and sustainable bioremediation strategies. Ultimately, this review provides valuable information to improve the efficiency and scalability of SRB-based remediation methods, contributing to more sustainable mining practices and environmental conservation. To ensure relevance and credibility, relevance and regency were used as criteria for the literature search. The literature sourced is directly related to the subject of the review, and the latest research, typically from the last 5 to 10 years, was prioritised. Full article

Microbial communities in wastewater treatment plants (WWTPs) play a crucial role in the decontamination of polluted water. An uncultured order-level lineage AKYH767 of the phylum Bacteroidota has been consistently detected in microbial consortia of activated sludge at WWTPs worldwide, but its functional role remains elusive. Representatives of AKYH767 were also detected in soils and freshwater bodies, which may be their natural reservoirs. Here, we obtained ten high-quality metagenome-assembled genomes, including one closed circular genome, of AKYH767 bacteria from metagenomes of the wastewater and activated sludge and used genomic data to uncover the metabolic potential of these bacteria and to predict their functional role. The cells of the AKYH767 bacteria were inferred to be rod-shaped and non-motile. Genome-based metabolic reconstruction predicted the Embden–Meyerhof pathway, the non-oxidative stage of the pentose phosphate pathway, and the complete tricarboxylic acid cycle. A facultatively anaerobic chemoheterotrophic lifestyle with the capacity to oxidize low organic substrates through aerobic respiration was suggested. Under anaerobic conditions AKYH767 bacteria can perform different steps of denitrification. They have limited capacities to hydrolyze carbohydrates and proteinaceous substrates but can utilize fatty acids. A peculiar property of AKYH767 bacteria is the presence of the phenylacetyl-CoA pathway for the utilization of phenylacetate, and about half of the genomes encoded the benzoate degradation pathway. Apparently, in bioreactors at WWTPs, the AKYH767 bacteria could be involved in the denitrification and biodegradation of aromatic compounds. Based on phylogenetic and genomic analyses, the novel AKYH767 bacterium is proposed to be classified as Candidatus Pollutiaquabacter aromativorans, within the candidate order Pollutiaquabacterales. Full article

This study assesses the impact of hydraulic retention time (HRT) on the performance of an anaerobic dynamic membrane bioreactor (AnDMBR) system using a carbon fabric membrane for treating high-strength wastewater. The evaluation of AnDMBR performance encompasses the removal of soluble chemical oxygen demand (sCOD), biogas/methane production, and membrane fouling. The average influent sCOD concentration was 11,814 ± 1064 mg/L, with two HRT applications at 8 and 5 days and high biomass concentration (MLVSS 14,600 ± 500 mg/L). An impressive sCOD removal efficiency exceeding 98% was achieved throughout the operation period. The AnDMBR system exhibited the highest biogas production, reaching 4.33 ± 0.51 L/day, with a methane content of approximately 67.77 ± 2.9% during the 5-day HRT stage. Transmembrane pressure (TMP) increased gradually at the 8-day HRT stage, leading to membrane fouling, whereas fouling occurred more rapidly at the 5-day HRT stage. Biomass analysis showed minimal variations in MLVSS, extracellular polymeric substance (EPS), and soluble microbial product (SMP) concentrations (protein and carbohydrate) across both HRT application stages. This study suggests that the AnDMBR system can be adopted effectively for treating high-strength wastewater, maintaining high COD removal efficiency and biogas production with 5-day HRT. Full article