Zhejiang Gongshang University

Achieving high-value valorization of food waste (FW) into medium-chain fatty acids (MCFAs) is vital for alleviating environmental pressure and advancing carbon neutrality. However, the inherent electron transfer and metabolic bottlenecks in FW bioconversion process restrains the conversion efficiency of MCFAs. Herein, the performance and comprehensive mechanisms of Fe₃O₄-enhanced MCFA production were comprehensively studied through integrated batch fermentation tests, bio-electrochemical characterizations, and metagenomic analysis. Results revealed that the optimal dosage of 8 g/L Fe₃O₄ enhanced caproate production to 3409.32 mg COD/L (a 3.7-fold increase over the control group). Notably, this dosage drove the further elongation of carbon chains, yielding high-energy-density heptanoate (C7) and caprylate (C8), thereby elevating MCFA selectivity from 5.5 % to 38.6 %. Further analysis indicated that Fe₃O₄ promoted all biological processes (solubilization, hydrolysis, acidogenesis, and chain elongation). Mechanically, Fe₃O₄ optimized the electrochemical microenvironment, enhancing conductivity and electron transport system (ETS) activity by 32.5 % and 69.1 %, respectively. The correlation-based network analysis confirmed a strong correlation (r > 0.4) between product distribution, iron cycling (Fe²⁺ concentration), and conductivity. Metagenomic analysis elucidated that by enriching core functional genera like Clostridium and Sphaerochaeta and associated functional microbial genes, Fe₃O₄ synergistically promoted the efficient bioconversion of FW into MCFAs. This study offers new mechanistic insights into enhancing MCFA production via magnetite-regulated electron transfer, providing a robust strategy for efficient resource recovery from complex organic wastes.

In recent years, the emergence of new environmental pollutants has drawn increasing attention to the plasmid-mediated conjugation transfer of antibiotic resistance genes (ARGs) induced by these contaminants. The widespread application of organophosphate esters (OPEs) has led to their frequent detection in aquaculture water, posing potential risks to the aquatic ecosystems and human health. In this study, we revealed that exposure to five types of OPEs (0.1-1000 µg/L) promoted the dissemination of RP4 plasmid from Escherichia coli to Pseudomonas alcaligenes, a multidrug-resistant bacterium isolated from actual aquaculture wastewater. Through the application of fluorescence detection, scanning electron microscopy, RT-qPCR, and RNA-seq techniques, we clarified at the cellular and molecular levels that OPEs promoted plasmid conjugation transfer by inducing reactive oxygen species (ROS) accumulation, activating the stress response (SOS), enhancing cell membrane permeability, improving intracellular energy supply, regulating the expression of conjugation-related genes, and activating the transfer apparatus encoded by RP4. Specifically, TBEP was selected as a representative OPE to systematically explore its impact on plasmid dissemination. Notably, a frequently overlooked aspect was that exposure to TBEP also enhanced the genetic stability and expression persistence of ARGs. Our findings emphasized that OPEs released from aquaculture facilities might act as driving factors to promote intergenus horizontal transfer of ARGs in actual aquaculture environments-a potential risk that has not yet been fully recognized.

Food allergy represents an increasing global health concern, with crustaceans recognized as one of the most prevalent and high-risk allergen sources. As the most globally consumed crustacean, shrimp harbors multiple structurally resilient allergens that resist conventional processing techniques, thereby maintaining a persistent allergenic risk across food systems. Because current clinical management remains limited, there is a critical need for upstream allergen mitigation strategies at the food level. This review synthesizes recent advances in shrimp allergen mitigation, focusing on structure and mechanism-oriented approaches rather than therapeutic intervention. Processing-based strategies, including thermal treatments, enzymatic modification, and emerging physical technologies, are discussed alongside molecular approaches such as epitope-directed modification and low-allergenicity protein design. Furthermore, dietary immunomodulation and microbiota-targeted strategies are highlighted as vital complementary pathways for indirect risk reduction. By integrating molecular insights with risk-oriented evaluation, this review provides a foundational framework for developing safer shrimp-derived foods and guiding future allergen control strategies.