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Fermentation

Fermentation is an international, peer-reviewed, open access journal on fermentation process and technology, published monthly online by MDPI.

Quartile Ranking JCR - Q2 (Biotechnology and Applied Microbiology)

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Heyndrickxia coagulans is widely used for industrial L-lactic acid production, but carbon catabolite repression (CCR) and its link to fermentative metabolism remain poorly understood. A ccpA deletion mutant (ΔccpA) and a complementation strain (C-ccpA) were constructed to investigated the physiological, enzymatic, and transcriptomic consequences of CcpA loss. Deletion of ccpA completely abolished glucose-mediated CCR, enabling simultaneous glucose–xylose co-utilization, and triggered a marked shift from L-lactic to mixed-acid fermentation, with an 82.5% reduction in lactate titer accompanied by 24.1-fold and 51.6-fold increases in acetate and formate, respectively. Enzyme activity assays showed that L-lactate dehydrogenase activity was reduced by half, whereas acetate kinase activity increased nearly six-fold. Transcriptomic analysis revealed downregulation of ldhL and upregulation of pflB and ackA. Scale-up fermentation in a 5 L bioreactor confirmed that the wild type directed 90.2% of carbon flux to lactate (yield, 0.95 g/g glucose), compared with only 24.5% in the mutant. All phenotypes were fully restored upon complementation. These results demonstrate that CcpA is as an indispensable dual regulator of both CCR and L-lactic fermentation, providing a foundation for rational metabolic engineering of H. coagulans.

13 March 2026

Construction and verification of ΔccpA and C-ccpA in H. coagulans. (A) Schematic of markerless ccpA deletion using the temperature-sensitive vector pMAD via two-step homologous recombination, yielding either WT reversion or the ΔccpA genotype after plasmid excision. (B) Colony PCR verification using flanking primers: Lane 1, WT (1864 bp); Lane 2, ΔccpA (868 bp); M, DL2000 DNA marker. (C) Relative ccpA transcript levels in WT, ΔccpA, and C-ccpA determined by RT-qPCR using 16S rRNA as the internal reference. Data are mean ± SD (n = 3 biological replicates). Statistical significance was determined by one-way ANOVA followed by Tukey’s post hoc test. *** p < 0.05 compared to WT.

We evaluated the algicidal properties of Bacillus Ba3 fermentation broth combined with clay for harmful algae bloom (HAB) control through in situ enclosure experiments in Suao Bay, China. It was indicated by the results that the combination significantly reduced HAB abundance, turbidity and phosphorous in water without affecting zooplankton and small fish. The treatment achieved 99.8% (Phase 1) and 100% (Phase 2, with sediment) removal rates for harmful dinoflagellates, primarily Prorocentrum donghaiense and Karenia mikimotoi, while demonstrating high taxonomic selectivity, allowing beneficial diatom populations such as Chaetoceros spp. to remain resilient. This synergy is attributed to clay acting as a physical carrier that brings adsorbed algicidal metabolites into direct, prolonged contact with algal membranes. This method shows promise for prolonged dinoflagellate control and may offer an economical and environmentally sound approach to HABs. More research is needed to establish its action on a wider scale in marine environments.

13 March 2026

Comparison of phytoplankton community structure and taxonomic richness before and after treatment. Data are categorized into (A) high-density algal enrichment groups and (B) low-density unenriched groups. Values represent the number of species (genera) detected across two phyla: Dinoflagellate and Diatom.

The roots of Panax ginseng are well known for their bioactive properties, while its berries have recently attracted attention for their pharmacological potential. This study investigated whether fermentation with Lactiplantibacillus plantarum enhances the antioxidant properties of ginseng roots and berries and their protective effects against oxidative stress in vitro. Fermentation significantly increased total polyphenol, flavonoid, and saponin contents and promoted the conversion of major ginsenosides (ginsenoside Rg1, ginsenoside Rb1, and ginsenoside Rb2), which are relatively less bioavailable, into minor ginsenosides (ginsenoside Rh1, ginsenoside Rg2, and ginsenoside Rg3) with enhanced biological activity and bioavailability. Fermented extracts exhibited higher radical-scavenging activities in 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and ferric reducing antioxidant power (FRAP) assays than non-fermented extracts. In tert-butyl hydroperoxide (t-BHP)-stimulated Chang liver cells, fermented extracts reduced intracellular reactive oxygen species (ROS) generation, inhibited lipid peroxidation, restored the reduced glutathione/oxidized glutathione (GSH/GSSG) ratio, and enhanced antioxidant enzyme activities, including superoxide dismutase (SOD) and catalase (CAT). These results demonstrate that L. plantarum-mediated fermentation effectively enhances the antioxidant and cytoprotective potential of ginseng roots and berries, supporting their application as functional food ingredients.

12 March 2026

Antioxidant activities of ginseng berry and ginseng root extracts and their fermented counterparts. (A) DPPH radical scavenging activity, (B) ABTS radical scavenging activity, (C) ferric reducing antioxidant power (FRAP), and (D) nitrite scavenging activity. EGB and FEGB indicate ethanol extracts of non-fermented and fermented ginseng berries, respectively, while EGR and FEGR indicate ethanol extracts of non-fermented and fermented ginseng roots, respectively. A.A indicates ascorbic acid, which was used as a positive control. Different lowercase letters (a–e) indicate significant differences among different samples at the same concentration according to Duncan’s multiple range test (p < 0.05).

Recent Advances in Microalgae Cultivation Systems: Toward Autonomous Architecture

  • Viyils Sangregorio-Soto,
  • Edgar Yesid Mayorga Lancheros and
  • Renata De La Hoz

Scaling up microalgae cultivation is key to commercial viability. Over the past two decades, the market value of microalgae has expanded exponentially, driven by their applications in the pharmaceutical, nutraceutical, cosmetic, and animal feed industries. High-value compounds such as omega-3 fatty acids, proteins, and pigments are in strong demand. However, supply remains constrained by suboptimal cultivation practices and high harvesting costs. Despite decades of progress in process modeling, control, and optimization, industrial adoption is still limited by dynamic cultivation conditions influenced by weather variability, biological adaptation, and integration challenges. Technical barriers, including limited data accuracy, modest control performance, and the fragility of low-cost devices, further restrict optimization efforts. In response, we examined recent advances in control, optimization, and automated machine learning applied to microalgae cultivation. We propose an automated architecture built on a closed-loop supervisory layer that embeds machine learning within the control loop, enabling real-time monitoring, prediction, and adaptive actuation. This approach aligns with real-time optimization and distributed control system practices, integrating system identification, controller optimization, fault diagnosis and tolerance, and perception to achieve autonomous, uncertainty-aware operation.

12 March 2026

Industrial hierarchical automation structure.

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Fermentation Processes
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Fermentation Processes

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Editors: Ricardo Aguilar-López
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Chemistry, Properties and Applications in Food Quality Improvement
Editors: Ana Leahu, Maria Soledad Prats Moya, Cristina Ghinea
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Fermentation - ISSN 2311-5637