Bioprocess and Biosystems Engineering最新文献

The rapid expansion of nanotechnology has opened novel opportunities to share for addressing global challenges related to food security, environmental sustainability, and human health. Conventional physical and chemical methods for the synthesis of nanoparticles (NPs) often involve hazardous chemicals, high energy demands, and poor biocompatibility. In contrast, bacterial-synthesized NPs are considered eco-friendly and multifunctional with their enormous potential in agriculture, bioremediation, and biomedical applications. The study highlights the importance of Bacteriogenic NPs as a sustainable alternative to chemically and physically produced NPs due to their reduced toxicity and lower energy consumption. Hence, bacteriogenic NPs, particularly those derived from Bacillus and Pseudomonas species, exhibit remarkable stability, biocompatibility, and multifunctional spectrum due to inherent reducing and capping biomolecules secreted by those bacteria. This review highlights the biosynthetic mechanisms, characterization techniques, and diverse applications of bacterial-based NPs. Initially, in agriculture, silver NPs synthesized by Bacillus xiamenesis enhanced rice growth while suppressing Xanthomonas oryzae, the causal agent of bacterial blight. Then, in environmental remediation, Bacillus pumilus-derived silver nanoparticles demonstrated 96.99% degradation of Congo red dye, underscoring their catalytic efficiency. And, in biomedical sciences, selenium NPs biosynthesized from Streptomyces minutiscleroticus exhibited antiviral activity against dengue virus type 1, highlighting their therapeutic promise. Key findings reveal that these NPs can enhance stress tolerance, nutrient uptake, and disease resistance, along with remediating harmful pollutants from the environment. They also exhibit strong antimicrobial and anticancer properties. Despite all these advancements, much work is still needed to optimize NPs' yield, uniformity, and functionality, as well as environmental and health safety assessment. Integrating omics approaches and nanobiotechnology innovations may unlock new opportunities for precision agriculture, environmental restoration, and advanced therapeutics. In a nutshell, bacterially mediated nanotechnology emerges as a sustainable and transformative tool to address pressing societal and ecological concerns.

Problematic clays are widely stabilized with lime to improve strength and durability, yet slow early-age strength development, pronounced brittle failure, and limited densification often constrain performance in high-alkalinity environments. This study explores a synergistic route that integrates diatomite-immobilized ureolytic microbially induced calcium carbonate precipitation with lime stabilization. Mixtures were prepared with 6% hydrated lime and 3 to 7% diatomite or a diatomite-based microbial curing agent; where applicable a 1.0 M urea-calcium chloride solution supplied substrates for mineralization. Mechanical properties were assessed by unconfined compressive strength, unconsolidated-undrained triaxial testing, and ultrasonic pulse velocity, and microstructure and phase assemblage were characterized using scanning electron microscopy, X-ray diffraction, and thermogravimetric analysis. Results show clear dosage-dependent gains. At 28 d, unconfined compressive strength reached 1987.18, 2278.17, and 2563.00 kPa for 3%DE-B, 5%DE-B, and 7%DE-B, exceeding the corresponding diatomite-only groups by 75.65%, 83.17%, and 88.50%. Under 300 kPa confining pressure, cohesion increased to 382.52 to 498.72 kPa and the internal friction angle to 38.88 to 47.88°. Ultrasonic pulse velocity rose with curing age, with 7%DE-B increasing by 45.01% from 7 d to 28 d. Triaxial responses followed linear elasticity, strain hardening, peak strength, and softening, while failure shifted from through-crack brittleness to non-through diffuse cracking with pronounced bulging. Microstructural evidence indicates clustered calcium silicate hydrate (C-S-H) progressively encapsulating diatomite and abundant ellipsoidal CaCO₃ forming interconnected three-dimensional networks. These observations support a synergy between pozzolanic reaction and microbial mineralization that constructs a multi-scale cementation network, densifies the matrix, and strengthens interparticle contacts, yielding reproducible improvements in strength, ductility, and structural integrity. These results provide reference value for performance enhancement and process optimization of lime-stabilized clays and cementation-enhanced clay systems.

Microbial bioelectrochemical technologies rely on the development of biofilms on electrode surfaces; therefore, a high surface area in packed anodes is advantageous for their performance. In addition, bioelectrochemical reactors (BERs) for hydrogen production require low-cost installation materials to enable large-scale implementation. In this study, a one-liter BER was constructed using 0.38 L of carbon felt as a packed bioanode, 0.65 L of compost leachate as the electrolyte, and a stainless-steel mesh cathode. The reactor was operated under an anode potential of 0.05 V vs. Ag/AgCl (KCl, 3.5 M) in batch cycles of 24 h each. After medium replacement, the maximum accumulated gas volume reached 2.37 L, corresponding to a production rate of 7.38 m⁻³ gas m⁻³ packed reactor d⁻¹. The cathode potential varied over time, leading to fluctuations in energy efficiency, which exceeded 100%. Average energy, cathode and coulombic efficiencies over eight operational cycles were 124 ± 64%, 118 ± 56%, and 120 ± 61%, respectively. The gas yield obtained from compost leachate in the BER was within the upper range of productivity reported for microbial electrolysis cells. This work demonstrates a sustainable alternative for BER installation and operation and proposes a monitoring strategy to track energy efficiency during hydrogen production.

Exopolysaccharides (EPS) are natural macromolecular carbohydrates with good functional activity and physiological activities, but their industrial application was limited by high production costs and unclear structure-function relationships. This study developed a circular economy strategy to produce EPS via microbial fermentation using two food processing wastes (cane molasses and soy sauce residue). After optimizing fermentation medium, the waste-based system achieved an EPS yield of 33.06 ± 0.54 g/L. Two heteropolysaccharides-EPS-2 and EPS-3 were successfully isolated and purified. Monosaccharide composition analysis revealed that EPS-2 primarily consisted of arabinose, glucose, and galactose in a ratio of 65.35:20.82:13.83. In contrast, EPS-3 exhibited a more complex profile containing rhamnose (33.54%), galactose (31.62%), fucose (17.93%), arabinose (13.47%), and glucose (3.44%). Notably, EPS-3 demonstrated higher antioxidant activity than EPS-2. This study successfully demonstrates an innovative waste-to-value conversion strategy that not only achieves high-value utilization of discarded resources but also establishes the fundamental theoretical framework for scalable production of renewable biopolymers.

Biological treatment of high-strength (above 500 mg/L NO₃^--N) nitrate wastewater is often limited by process instability, nitrite accumulation and nitrous oxide (N₂O) emissions. This study developed a synergistic biochar-bacteria hybrid system by coupling a non-N₂O-accumulating denitrifier (Citrobacter freundii XY-1) with biochar (BC550) derived from spent mushroom substrate. Pyrolyzed at 550 ℃, BC550 exhibited high electron transfer capacity and served as a multifunctional carrier, facilitating biofilm formation and enabling high-rate nitrate removal. In a continuous-flow biofilter treating 1200 mg/L NO₃^--N, the system maintained a nitrate removal efficiency exceeding 97.5% for over 100 days at a hydraulic retention time of 15 h and C/N ratio of 10, with effluent nitrite consistently below 3 mg/L. Microbial community analysis confirmed the stable dominance of the inoculated XY-1 strain (39.7%), demonstrating successful bioaugmentation and system resilience. This work presents a stable and environmentally friendly hybrid system for high-strength nitrate removal, achieved through the rational coupling of functional biochar with a specific beneficial microorganism to ensure high treatment efficiency and mitigate N₂O emission risk.

Low influent carbon-to-nitrogen (C/N) ratios often limit denitrification in municipal wastewater treatment systems. This study evaluated denitrification performance in a full-scale anaerobic-anoxic-oxic (AAO) process equipped with a 6 m-deep anoxic tank containing spherical fixed carriers. Sludge flocs and carrier-attached biofilms were sampled at depths of 1 m, 3 m and 5 m along the horizontal flow path. Denitrification kinetics were quantified using batch tests, and microbial community structures were analyzed by 16 S rRNA gene sequencing. Sludge flocs exhibited the highest denitrification rates at 1 m, whereas biofilms performed optimally at 3 m. Along the horizontal direction, sludge flocs near the influent and external carbon dosing site showed enhanced denitrification, while biofilms downstream of the propeller demonstrated improved denitrification. Elevated dissolved oxygen (DO) introduced by internal reflow reduced the effective utilization of the external carbon source. Nitrosomonas was more abundant in sludge flocs, whereas Thauera dominated denitrifying community and peaked at 3 m in biofilms. Based on the spatial distribution of denitrification kinetics and microbial communities, the conventional "pre and top" carbon dosing strategy was re-evaluated, and an optimized "post and top" dosing strategy was proposed. This strategy reduced chemical oxygen demand (COD) consumption per unit of total nitrogen (TN) removed by 16%, providing a practical approach to enhance denitrification efficiency and external carbon utilization in full-scale anoxic tanks.

Electrospun nanofibers have attracted significant interest due to their high surface area-to-volume ratio, porosity, interconnected voids, and advantageous mechanical, chemical, and physical properties. Enzymes, known for its exceptional catalytic properties, are promising candidates for various industrial applications. However, the use of free enzymes is limited by challenges such as poor recyclability and susceptibility to environmental factors. Immobilization techniques offer a viable solution by enhancing the stability and activity of enzymes. This review compares four enzyme immobilization methods to identify the most effective strategy and focuses on the various approaches to optimize electrospinning methods, as well as parameters to maximize enzyme loading, activity retention, and stability. Among the various immobilization methods, entrapment and encapsulation of enzymes within electrospun nanofibers have garnered significant attention in recent years. The review discusses the applications and challenges associated with enzyme entrapment and encapsulation using electrospinning. Overall, advancements in electrospun nanofibers with encapsulated or entrapped enzymes highlight their potential as robust, efficient, and sustainable platforms for biosensors, therapeutics, antimicrobial applications, smart textiles, as well as food and wastewater treatment processes. Subsequently, future research should focus on scalable electrospinning processes, the development of eco-friendly materials, long-term enzyme stability, multi-enzyme systems, and a deeper mechanistic understanding to further enhance performance and safety.

The rising global demand for sustainable energy has directed significant attention towards biohydrogen production via dark fermentation of organic wastes. Accurate yield prediction is crucial for optimizing process conditions and enhancing overall process. This study aims to develop a robust and interpretable predictive framework that integrates kinetic modeling with a hybrid Bayesian Optimization-Artificial Neural Network (BO-ANN) approach for precise biohydrogen yield prediction. The core novelty lies in representing each substrate not as a simple category, but by its quantitative kinetic parameters from the Modified Gompertz equation, providing a biologically meaningful input. A comprehensive database compiled from the literature incorporates key process variables, including temperature, pH, residence time, and substrate concentration, along with kinetic parameters from the Modified Gompertz equation characterizing each substrate. The BO algorithm was employed to optimize the ANN architecture, and 5-fold cross-validation was used to evaluate model generalization ability. The proposed hybrid model achieved outstanding predictive performance (R² = 0.9980, RMSE = 0.0117, MAE = 0.0062), confirming its accuracy and robustness. Furthermore, SHAP analysis and correlation metrics provided interpretable insights into feature contributions, particularly the relevance of kinetic descriptors. Overall, the proposed BO-ANN framework offers a scalable, interpretable, and biologically grounded tool to improve predictive accuracy and support the design of more efficient and sustainable biohydrogen production systems.