Bioprocess and Biosystems Engineering最新文献

Over the past few decades, the study of novel methods to control the size and morphology of inorganic and organic materials has been the focus of current research. Recently, green synthesis approaches for the synthesis of nanoparticles have garnered significant attention due to their use of eco-friendly and non-toxic substances. These methods are simple, cost-effective, and help in synthesizing thermally and chemically stable nanoparticles. This review article illustrates the detailed study of the utilization of bio-templates, such as parts of plants (e.g., leaves, seeds, etc.), bacteria, viruses, fungi, algae, etc. These biological systems act as reducing and stabilizing agents, which help in the formation of copper nanoparticles (CuNPs) with controlled morphology and size. Copper metal was selected due to its great utility, high biocompatibility, and lower side effects. Here, the authors have reviewed the mechanism of formation of CuNPs by bacteria, algae, fungi, and plants, in addition to the characterization of CuNPs. Further emphasis has been given on the multifaceted application of green CuNPs in healthcare (antibacterial, anticancer, etc.), sensing, environmental remediation (dye removal and pollutant removal), and agriculture. This review also identifies current challenges and outlines the future scope of CuNPs in various emerging fields.

Bioaugmentation of anaerobic digestion (AD) systems is considered a cost-effective and environmentally friendly strategy to combat incomplete digestion of recalcitrant lignocellulosic substrates. This study investigated the lowest microbial inoculum size required for once-off bioaugmentation of AD cultures to enhance biomethane yield and process performance. The batch, laboratory-scale anaerobic co-digestion was carried out using pretreated corn stover (PCS) and food waste (FW), with cellulolytic Bacillus subtilis, Serratia marcescens and Bacillus licheniformis. The bioaugmentation screening was accomplished through a stepwise increase in the microbial loading using an initial standardised concentration of 0.4 × 10¹¹ colony-forming units (CFU)/mL within the system. Bioaugmentation decreased the digestion time by up to 11 days. The inoculation of B. subtilis at a microbial concentration of 20 × 10¹¹ CFU/mL (4.85 g DCW/L) improved the biomethane yield by 34% compared to the unaugmented control and produced 525 NmL CH₄/gVS. Additionally, S. marcescens at 12 × 10¹¹ CFU/mL doubled the volumetric methane productivity from 0.47 ± 0.02 to 1.04 ± 0.02 mL/(mL.day) when compared to the unaugmented control. The application of Nanopore sequencing after AD, to investigate the microbial community dynamics and structure in this treatment, underlined 43.52, 7.69 and 25.26% increases in the bacterial alpha diversity, namely the Shannon-, Simpson- and Observed indices, respectively. Moreover, a high abundance of between 50 and 80% of the Firmicutes population was identified.

Zika virus (ZIKV) was declared a public health emergency in 2016, yet effective vaccines are still needed. Among the immunization platforms under evaluation, virus-like particles (VLP) are promising candidates. Growth, metabolism, and respiration are among the cell host processes that are essential for optimizing and characterizing VLP upstream production stage. These cell functions can be influenced by factors such as culture medium composition and the multiplicity of infection (MOI) in viral vector-based expression systems. This study investigated the effects of three MOIs (2, 6, and 10) in a baculovirus/Sf9 insect cell system on ZIKV VLP production with and without medium supplemented with 0.028 mM cholesterol and 6 nM albumin. Medium supplementation during the growth phase increased the cell growth rate from 0.357 × 10⁴ to 0.565 × 10⁴ $\frac{\text{cells}}{\text{mL}·\text{h}}$ . In addition, cholesterol and albumin supplementation increased the expression of ZIKV structural proteins during infection. Higher MOIs led to increased substrate uptake and metabolite production, suggesting intensified cellular metabolism. Western blot analysis revealed that under nonsupplemented conditions, the highest MOI resulted in increased ZIKV envelope production, with a maximum protein concentration range of 1.049 $\frac{\text{mg}}{\text{L}}$ higher when comparing 6 to 2 $\frac{\text{PFU}}{\text{cell}}$ MOI via SDS‒PAGE densitometry. However, a lower MOI, 2 $\frac{\text{PFU}}{\text{cell}}$ , might be advantageous when a supplemented medium is used, which upper limit for ZIKV envelope protein concentration was 1.834 $\frac{\text{mg}}{\text{L}}$ higher than that from the nonsupplemented assay in semiquantitative analysis, which reached 23.504 $\frac{\text{mg}}{\text{L}}$ of ZIKV envelope protein. The resulting VLP had an average diameter of ~ 60 nm, making them suitable for vaccine applications.

The bioremediation of penoxsulam, a commonly encountered aquatic herbicide, was investigated using a single-chamber air microbial fuel cell (MFC) system. This study focused on how the modulation of electron transfer through exogenous electron shuttles (riboflavin (RF), anthraquinone-2-sulfonate (AQS)) and respiratory inhibitors (rotenone, capsaicin) affects electrogenesis and the degradation of penoxsulam. The addition of electron shuttles significantly improved both MFC power generation and pollutant removal efficiency in a dose-dependent manner, with optimal concentrations identified for maximum performance. In contrast, respiratory inhibitors strongly suppressed both processes, leading to an increase in charge transfer resistance. This study links macroscopic changes in performance with intracellular bioenergetic parameters, showing that electron shuttles maintain higher intracellular NAD⁺ levels and current densities, likely by promoting NAD⁺ regeneration, whereas inhibitors deplete NAD⁺ availability and hinder electron flow. Additionally, an analysis of key respiratory enzymes indicated that Cytochrome C oxidase plays an important role in facilitating extracellular electron transfer to the anode. Inhibitor studies provide further support for the importance of Complex I and downstream cytochrome pathways for power generation and degradation. By establishing the relationships between mechanisms and performance and proposing an integrated electron transfer model, this research highlights important enzymatic and metabolic control points for optimizing MFC-based bioremediation. These findings provide important insights into enhancing bioelectrochemical systems for concurrent environmental remediation and sustainable energy recovery.

Pseudomonas aeruginosa infections and biofilms are difficult to treat due to their remarkable ability of antibiotic resistance. Consequently, the incidence of drug-resistant P. aeruginosa infection cases is steadily increasing in hospitals worldwide. Herein, the frequency of drug-resistant P. aeruginosa wound infection cases among hospitalized patients is examined. In addition, suitable natural components with potent antibacterial activity against the drug-resistant P. aeruginosa strains are screened. Among 27 specimens, three P. aeruginosa strains (including carbapenem and multidrug-resistant) are isolated. The antibacterial efficacy of natural components, such as curcumin, naringin, quercetin, tannic acid, and rutin, is evaluated against the isolated drug-resistant P. aeruginosa strains. Comparatively, naringin showed great antibacterial potential against drug-resistant P. aeruginosa strains. The zone of inhibition is found between 13 and 16 mm for naringin (20 mM) against P. aeruginosa strains; while, the minimum inhibitory concentration is found between 10 and 14 mM. A complete eradication of bacterial cells in P. aeruginosa mature biofilm is achieved by naringin at 28 mM within 24 h. Naringin interacts with the most important amino acids found in the MexR and RlpA, which confirms its role in the targeted treatment of drug-resistant P. aeruginosa. Remarkably, naringin is found to be hemocompatible up to 30 mM. Overall, this study suggests that naringin might be an outstanding biocompatible natural component to effectively treat multidrug-resistant P. aeruginosa infections and biofilms.

This study focuses on the glutamate-dependent strain Bacillus subtilis SCP017-03, systematically investigating its metabolic mechanism for synthesizing γ-polyglutamic acid (γ-PGA) in the presence of exogenous glutamate, as well as optimizing its fermentation conditions. Metabolomic analysis revealed that glutamate addition significantly altered the cellular metabolic profile, with 480 out of 1674 metabolites showing differential expression. Notably, pathways such as the TCA cycle, glycolysis, glutathione metabolism, and amino acid metabolism were significantly upregulated, enhancing precursor supply and energy metabolism, thereby promoting γ-PGA synthesis. Based on these findings, fermentation conditions were optimized in a 5-L bioreactor. Yeast extract was identified as the optimal nitrogen-rich nutrient, and at an addition level of 7.5 g/L, the γ-PGA yield reached 87 g/L. The optimal conversion efficiency and yield were achieved with a 5% addition of monosodium glutamate. Molecular weight analysis showed that the resulting γ-PGA predominantly ranged from 1071 to 4897 kDa, making it suitable for agricultural applications. In a 30-L scale-up fermentation, γ-PGA production reached 71 g/L through optimized aeration, agitation, and feeding strategies, demonstrating the scalability of the process. Finally, optimized spray-drying conditions (inlet temperature of 160 °C) resulted in a 67% recovery rate with a desirable product appearance. This study provides important metabolic regulation strategies and engineering optimization foundations for the efficient industrial production of γ-PGA.

Algae-assisted biological wastewater treatment technology has been widely applied in wastewater treatment due to its low cost and great removal performance. However, the stabilization and sustainability of the alga-bacteria symbiosis system still need to be developed. In this work, an algae-assisted sequencing batch and intermittent air-lift bioreactor (A-SBIAB) system was constructed for removing the nutrients from the piggery wastewater. A strengthened algae-bacterial symbiosis system was also achieved with the aid of a suspended bio-carrier composed of polyester filament fixed on concentric plastic rings, which provided enhanced surface area and illumination access for microbial attachment. The removal efficiencies of chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP) were up to 92.0%, 81.7% and 89.3%, respectively, at the optimum parameters (Chl-a concentration of 1000 mg/m³, light intensity of 6000 lx and lighting time 10 h). The Campylobacteria (72.05%), Desulfuromonadia (11.16%), Spirochaetia (3.10%) and Bacteroidia (1.73%) as the dominant bacterial communities would be responsible for the nitrate ammonification, nitrogen fixation, nitrate reduction and organics degradation, respectively. Meanwhile, Chlorophyceae (98.21%) became the overwhelming algal community, playing a positive effect on the nutrients removal.

Rhamnolipids (RLs) are glycolipid bio-surfactants produced by microorganisms with applications in industries, including environmental remediation and oil recovery, comparable to chemical surfactants. However, the reproducibility and scalability of RLs production in shake flask systems limit their industrial use, prompting the need for advanced bioreactor systems. This study aims to address this challenge by optimizing RLs production by Pseudomonas aeruginosa RS6 using treated waste glycerol (TWG), a low-cost by-product of biodiesel production, as a carbon source. Response surface methodology (RSM) was employed to evaluate the combined impact of TWG concentration, aeration, and agitation rates on RLs production and microbial behavior within a bioreactor system. Optimal conditions were then determined using central composite design (CCD) and analysis of variance (ANOVA). ANOVA revealed that the quadratic model significantly predicts RLs production (p < 0.0001). TWG concentration significantly influences RLs yield (p < 0.05), while TWG concentration and agitation rates significantly affect biomass production (p < 0.05). Optimal conditions were 2.827% TWG, 1.02 vvm aeration, and 443 rpm agitation. The model's validity was confirmed, yielding 11.32 g/L RLs and 5.38 g/L biomass. Kinetic studies showed Y_X/S and Y_P/S values of 5.53 g/g and 3.36 g/g, indicating efficient substrate utilization and metabolite production. RSM optimization enhanced RLs yield by 4.88-fold compared to shake flask results. The produced RLs achieved a kerosene emulsion index of 70.12% and reduced surface tension to 28.61 mN/m, highlighting their potential in environmental remediation. This study addresses the scalability issues in RLs production, and highlights the feasibility of using waste glycerol for large-scale RLs production.

The demand to accelerate monoclonal antibody (mAbs) process development timelines using Chinese hamster ovary (CHO) host cells to bring therapies to patients sooner is gaining momentum. The applicability of single use high-throughput (HTP) bioreactor system such as Ambr^®250 facilitating precise and automated control is very promising. This entails optimizing process parameters through design of experiments (DoE) using less resources and time, compared to traditionally employed large-scale bench top reactors (2-5L). It is imperative to improve mAb productivity through robust process development to mitigate current manufacturing challenges. In this study, a systematic mapping approach was employed to identify critical process parameters (CPP) and improve process efficacy. A central composite design (CCD) was used in Ambr^®250 bioreactors to investigate the impact of initial seeding density (SD) and feeding rate (FR) on mAb production. Variance in the SD and FR impacted the cell performance and mAb titer profile based on which parameter optimization was done using response surface methodology. Significant impact of FR and SD was identified leading to improved mAb titer. Bioreactors operated at SD > 1 × 10⁶ cells/mL and FR of > 2% Vc/day were more productive, and respective optimal FR and SD were estimated at 2.68% Vc/day and 1.1 × 10⁶ cells/mL. Cell viability and productivity were well-maintained at optimal conditions allowing extended cultivation time to reach higher mAb titer of up to 5 g/L. These findings, which optimize the operating range of critical process parameters (CPPs) using the high-throughput Ambr® 250 scaled-down platform, provide a framework for accelerated early-phase process development and enable reliable scalability to commercial manufacturing. Improving productivity and providing robust estimates for manufacturing scale would significantly cut costs and reduce timelines for biologics development and facilitate patient access.

Yarrowia lipolytica has been studied for poly (ethylene terephthalate) (PET) depolymerization, but the slow kinetics must be improved for large-scale applications. Here, dimethyl sulfoxide (DMSO) was added to a medium containing post-consumer PET (PC-PET) or the monomers terephthalic acid (TPA), bis(hydroxy-ethylene) terephthalate (BHET), and methyl-2-hydroxy ethylene terephthalate (MHET) to increase its solubility and improve depolymerization. The MIC test indicated 5% of DMSO as the maximum non-toxic concentration for Y. lipolytica cultivation. Cell viability on yeast nitrogen-based (YNB) medium was higher with MHET (94%). Cell growth in YNB medium and PC-PET was only detected with DMSO. When PC-PET was used as an additional carbon source, cell growth was 40% higher in the presence of DMSO (10.7 g/L), exhibiting increased adhesion of cells to PET (20%). Also, the highest extracellular lipase activity (370 U/L) was found with DMSO and PC-PET in flasks. In a bioreactor, higher cell growth (32.6 g/L) and lipase activity (7531 U/L) were obtained in YP*D medium with PC-PET and DMSO. During cultivation in this medium, TPA, MHET, and BHET were detected, demonstrating PET depolymerization along Y. lipolytica growth with DMSO. These results show that DMSO contributes to PET depolymerization by Y. lipolytica, increasing cell concentration, adhesion to PET particles, and enzyme production.