Bioprocess and Biosystems Engineering最新文献

The shift toward sustainable biofuels and bioproducts has increased interest in microbial production systems using renewable substrates. This study explores the use of wood hydrolysate, an abundant, cost-effective lignocellulosic substrate, as the primary carbon source for lipid and carotenoid production by Rhodosporidium toruloides-7191 under fed-batch cultivation in a 3-L bioreactor. The fed-batch strategy, chosen over batch and continuous modes, enables controlled nutrient supply, minimizes substrate inhibition, and maintains a favorable carbon-to-nitrogen ratio, thereby supporting prolonged biosynthesis and higher product yields. The process achieved a maximum lipid production of 22.33 g/L, a total lipid accumulation of 57.9% and a total carotenoid production of 4.23 mg/L. Fatty acid analysis shows a composition rich in linoleic acid (C18:2), oleic acid (C18:1), and palmitic acid (C16:0), indicating its suitability for biodiesel applications. The results emphasize R. toruloides-7191 as a promising candidate for industrial-scale applications, advancing sustainable production of biofuels and high-value bioproducts. The effectiveness of wood hydrolysate as a substrate further supports the feasibility of this approach, highlighting its potential in advancing industrial-scale processes for the production of biofuels and value-added compounds.

Butanol selectivity is crucial for the development of an industrial process targeting butanol as the main product of acetone-butanol-ethanol (ABE) fermentation by solventogenic Clostridia. This study evaluated electro-fermentation (EF), with an electron carrier, methyl viologen (MV), as a strategy to modify solvent production in Clostridium acetobutylicum ATCC 824 under optimized batch fermentation conditions. Cathodic EF was performed with or without 0.5 mM MV in single-compartment reactors with two-chamber and a negative potential was applied to the cathode. The greatest differences in final products concentrations were observed with the addition of MV compared to the control and EF fermentations. The fermentation with MV only was slowed down and resulted in 11% more butanol (control: 14.2 g.L^-1, MV: 15.8 g.L^-1) and half as much acetone, increasing the butanol/acetone (B/A) ratio by 137% from 1.93 to 4.57 g C.g C^-1. The pH profile was also modified with a final pH 0.5 unit higher. Conversely, EF did not appear to alter product formation significantly, even if slight differences were observed under our conditions. In addition, the reductase activity (RA) was measured by flow cytometry and showed that EF alone affected the intracellular redox state compared to the control fermentation, as did the addition of MV. However, electrode polarization had no effect on the extracellular oxidoreduction potential (ORP) profiles.

Chinese hamster ovary (CHO) cells are the most widely used host for the commercial production of recombinant therapeutic proteins. The rapidly growing demand for large quantities of biologics at controllable cost-of-goods requires continuous cell engineering and process optimization of the CHO host cells. MicroRNAs (miRNAs) have been shown to enhance recombinant protein production in CHO cells. While studies have demonstrated that transient overexpression of certain miRNAs can increase recombinant protein yields, systematic comparisons of different miRNA overexpression forms (primary, precursor, and mature) remain limited. Furthermore, their application in stable cell line development, particularly for difficult-to-express proteins, has yet to be thoroughly explored. This study evaluated three miRNA overexpression strategies: primary miRNAs (pri-miRNAs), precursor miRNAs (pre-miRNAs), and flanked mature miRNAs (incorporating the mature sequence plus reverse complementary and loop sequences), to enhance the expression of difficult-to-express proteins in stable CHO cell lines. Notably, these miRNA constructs were built-in with the gene of interest (GOI) on the same vector to simplify stable cell line generation. Our results indicate that the pre-miRNA overexpression strategy is the most effective. Overexpression of premiR-92a, premiR-200a, premiR-483, and premiR-106b significantly increased the expression level of a bispecific antibody (BsAb) and an Fc-fusion protein without compromising product quality. Further clone evaluation of the premiR-92a and premiR-483 overexpression groups revealed an improved proportion of high-productivity and stable clones. In conclusion, this study demonstrates that integrating pre-miRNA expression cassettes into therapeutic protein vectors for co-expression is a valuable and effective engineering strategy for developing a robust stable CHO expression platform.

The development of innovative bioprocessing technologies has resulted from the growing global need for sustainable forms of energy and environmentally friendly waste treatment. In this review, we focus on the combined electro-fermentation and microbial fuel cells, as they form a hybrid system that simultaneously addresses wastewater treatment, bioenergy production, and bioplastics. Even though microbial fuel cells produce electricity out of the organic waste by the use of electroactive microorganisms, electro-fermentation improves the microbial pathways through the external electrochemical management. The novelty of the review is that it compares the two technologies in detail and identifies the synergistic potential of the technologies as well as assesses the efficiencies of their operations, scalability, and impact on the environment. The research utilizing Scopus and PubMed directories was done by means of a systematic literature review that included 147 peer-reviewed experimentation and technology-oriented studies published during the period of 2012-2024. The main results lead to the conclusion that integrated systems imply significant increase in power densities (up to 2000 mW/m²), the enhancement of electron transfer efficiency (increased by 30-40%), large-scale production of useful products such as methane, hydrogen and organic acids. In spite of this promise, there are still difficulties regarding microbial stability, material costs, and energy balance. The review identifies the existing gaps and future opportunities, which include the development of novel electrode materials, the employment of better reactor designs and designer microbial consortia. The combination of such systems may become an interesting strategy of the next generation of biorefineries and have a good prospect to become a part of the circular economy and climate as a whole.

Concrete durability is compromised by its susceptibility to cracking, necessitating innovative solutions like self-healing concrete (SHC). Scopulariopsis brevicaulis is capable of biomineralization and its spores were found to hold high potential for use in SHC. Realizing this potential requires clean and effective production of S. brevicaulis spores, which remains unexplored. Here the factors and processes conducive to high productivity of S. brevicaulis spores were investigated. Suitability of cheap, renewable soy-based substrates: soy molasses (SM), soy hull (SH), and soy flour (SF) were first evaluated, and SH was found suitable. The comparison of SH-based solid-state fermentation (SSF) with submerged fermentation (SmF) revealed SSF's superiority, producing spores earlier and with a more than 4.5-fold higher rate. Further study of SSF parameters, including initial spore inoculum, moisture, SH particle size, sugar supplementation, N-source supplementation, pH, salt addition, light (vs. dark) condition, and occasional mixing/shaking plus water addition, highlighted conditions that significantly boost spore production. Optimal moisture content (60-67%) and elevated medium pH (10-11) and salt addition (15 g/L NaCl) were key to enhancing yield, the latter likely induced stress-driven sporulation. Using larger SH particles (> 850 µm) also proved beneficial, improving oxygen transfer. Electron microscopy confirmed the effective attachment and penetration of spore chains into SH particles. This work significantly improved the technical and economic feasibility of producing S. brevicaulis spores for industrial SHC development.

With the increasing application of copper nanoparticles (CuNPs) as antibacterial agents, numerous studies have emerged in recent years focusing on their preparation and utilization. However, the existing physical and chemical processes for CuNPs synthesis are complex and environmentally hazardous, creating a demand for greener alternatives. Komagataella phaffii has been recognized as a cost-effective system for metal biosorption. Nevertheless, high concentrations of heavy metal particles inhibit cell growth and result in low biosorption efficiency of metal-based nanoparticles (NPs). To address this issue, we engineered the K. phaffii strain X-33-Cyb5R by expressing the cytochrome b-5 reductase (Cyb5R) enzyme, enhancing its tolerance to elevated heavy metal concentrations and promoting CuNPs biosorption. Through further optimization of biosorption conditions, CuNPs production reached 14.27 mg/g dry cell weight (DCW) after 36 h, utilizing 12 mmol/L CuSO₄ at 30 °C and pH 4. The adsorbed particles on the surface of the modified strain K. phaffii X-33-Cyb5R were confirmed to be CuNPs with diameters ranging from 40 to 80 nm. Notably, the CuNPs synthesized in this study exhibited potent antibacterial activity. This research not only provides a novel approach for the construction of highly metal-tolerant strains and efficient CuNPs production but also offers new insights for the development and utilization of environmentally friendly antibacterial agents.

In this research, silver-decorated zinc oxide nanoparticles (ZnO-Ag NPs) were fabricated using Aesculus hippocastanum fruit extract (ZnO-Ag@AHFE NPs), and their catalytic and antimicrobial properties were studied. The nanoparticles were identified using XRD, TEM, and FT-IR analyses, which confirmed their spherical morphology, uniform structure, and particle sizes ranging from 50 to 70 nm. The ZnO-Ag@AHFE NPs illustrated high antibacterial performance compared to the extract and ZnO NPs alone, achieving a minimum inhibitory concentration (MIC) of 125 µg/mL against Escherichia coli and Pseudomonas aeruginosa. Additionally, the ZnO-Ag@AHFE NPs exhibited outstanding photocatalytic efficiency, degrading methylene blue and rhodamine B dyes by 97.6% and 94.3%, respectively, surpassing the performance of other catalysts. Antioxidant assays revealed that the nanoparticles inhibited 85% of DPPH free radicals, underscoring their potential in biological applications. This study presents a green method using A. hippocastanum fruit extract, offering an innovative approach to enhance the antibacterial, catalytic, and antioxidant properties of ZnO-Ag NPs. These findings highlight the transformative potential of green synthesis strategies for the development of multifunctional nanomaterials.

Pristinamycin (PST), produced by Streptomyces pristinaespiralis NRRL ISP-5338, is a streptogramin antibiotic with remarkably broad-spectrum bactericidal activity. The production of PST from its natural producer remains challenging. In the literature, a few reports examined PST production using submerged liquid fermentation (SLF). However, the literature survey revealed no reports that studied its production using solid-state fermentation (SSF). To our knowledge, this is the first report about the production optimization of PST using SSF. Therefore, in this study, we aimed to optimize various nutritional and environmental factors influencing its production as one-factor-at-a-time (OFAT) or as a multifactorial response surface method (RSM) using SSF. Three factors, including types of solid substrates, composition of the moistening broth, and incubation time, were optimized as OFAT. The OFAT optimal conditions were wheat bran as a solid substrate, IPS5 as a moistening broth, and 9 days as incubation time. These conditions increased PST production from 0.395 to 0.467 mg/g initial dry substrate (IDS). Using RSM, three factors--the initial pH of the moistening broth, the incubation temperature, and the inoculum size (v/w)--were statistically optimized, and the model was statistically significant with a p-value < 0.05. It resulted in a 2.3-fold increase in PST production (0.910 mg/g IDS) compared to the unoptimized SSF conditions (0.395 mg/g IDS) and a 5.35-fold increase from that obtained by the SLF (0.170 mg /mL). In conclusion, the SSF is an efficient and simple method for PST production, and the optimized conditions are highly recommended for scaling up.

Daqu is a traditional Chinese brewing ingredient that serves dual functions of saccharification and fermentation during the brewing process. The acidity content during the Daqu fermentation process directly affects the quality of the Daqu. Traditional methods for measuring Daqu acidity are complex and exhibit lag, making it difficult to monitor fermentation acidity in real time. Given the strong correlation between Daqu acidity and environmental variables, this paper proposes a time series prediction model for Daqu acidity based on the KNN-Attention-LSTM-XGBoost model. Upon collecting and analyzing the microenvironmental parameters of Daqu, the XGBoost model was used to select two optimal imputation methods (LFBI and KNN). Partial Least Squares Regression (PLSR) was employed to extract key parameters, and feature extraction using the lag and rolling window methods was performed to capture temporal trends and fluctuations. Comparative analysis revealed that KNN preprocessing combined with the Attention-LSTM-XGBoost model performed best in predicting Daqu acidity, with R² values reaching 0.9790, 0.9768, and 0.9636 for the upper, middle, and lower Daqu layers, respectively. This combination outperformed the LSTM-XGBoost and XGBoost models, with improvements of 3.87%, 1.11%, and 2.84% compared to LSTM-XGBoost, and 4.70%, 4.37%, and 8.46% compared to XGBoost. This study addresses the challenge of predicting Daqu acidity during fermentation and provides insights into the optimization of the Daqu fermentation process.

This study aimed to identify and characterize bioactive peptides derived from protein hydrolysates of Arthrospira platensis (APPH) and Tetraselmis chuii (TCPH) using an integrated peptidomics and bioinformatics approach. Proteins extracted from the microalgae were hydrolyzed using pepsin (EC 3.4.23.1) at various enzyme/substrate (E/S) ratios. APPH and TCPH, prepared at an E/S ratio of 1/10 (w/w), were analyzed using peptidomics through reverse-phase high-performance liquid chromatography (RP-HPLC) coupled with tandem mass spectrometry (MS/MS). Using the UniProtKB database, a total of 265 unique peptides were identified, including 187 peptides from APPH and 78 peptides from TCPH. Subsequent in silico analysis of these peptides revealed favorable physicochemical properties, with a notable distribution of hydrophobic (APPH: 26; TCPH: 5), amphipathic (APPH: 70; TCPH: 16), and hydrophilic peptides (APPH: 59; TCPH: 17). Toxicity assessments confirmed that none of the peptides showed hemolytic or cytotoxic risks, except for one peptide identified in TCPH with potential cytotoxicity. Furthermore, bioactivity predictions demonstrated significant multifunctional properties (scores exceeding the 0.500 threshold), identifying peptides with antihypertensive (APPH: 2; TCPH: 1), anti-diabetic (APPH: 2), anti-inflammatory (APPH: 14; TCPH: 5) and antimicrobial (APPH: 7) activities. The current study thus establishes protein hydrolysates from A. platensis and T. chuii as promising sources of bioactive peptides suitable for nutraceutical applications. Our integrated analytical and computational strategy provides critical insights into peptide multifunctionality, supporting further research and development of microalgae-derived peptides.