Global agriculture faces unprecedented challenges, including a projected population of 10 billion by 2050, declining arable land, and the urgent need to phase out antibiotic growth promoters (AGPs) to stem antimicrobial resistance (AMR). This review evaluates fermentation technology as a sustainable solution to the “food–feed–fuel” three competing land uses. We systematically compare solid-state fermentation (SSF) and submerged fermentation (SmF), highlighting their quantitative advantages: SSF offers 2–3× higher volumetric productivity and 70–90% lower water usage for solid wastes (e.g., soybean meal, wheat bran), while SmF provides superior process control for high-value products (e.g., single-cell protein). Key molecular mechanisms are discussed, including enzymatic degradation of anti-nutritional factors (up to 95% phytate and 98.8% tannin removal), mycotoxin detoxification (60–80% reduction), and biosynthesis of bioactive compounds (e.g., vitamin B12 enrichment up to 15-fold). Fermented feeds benefit many livestock species, particularly in organic and high-density farming systems, improving growth performance, gut health, and disease resistance while reducing environmental footprints. Advanced technologies such as AI-driven digital twins, CRISPR-based strain engineering, and precision fermentation are explored to overcome bottlenecks, including heat dissipation, strain stability, and process control. Despite challenges in scale-up, economics, and divergent global regulations (EU, USA, China, Southeast Asia, and Africa), fermentation is a critical biotechnological paradigm for circularity—the circular bioeconomy—and long-term food security. Future research should prioritize cost-effective large-scale implementation and the harmonization of regulatory frameworks.

This study investigated the influence of dietary supplementation with Bacillus subtilis natto (BSN) on various physiological parameters in red sea bream (Pagrus major). Key areas of focus included growth performance, enzymatic activity related to digestion, blood biochemical markers, immune function, and intestinal microorganisms. Fish were fed diets containing the following five levels of BSN: 0 (BN0), 1 × 10⁷ (BN1), 1 × 10⁸ (BN2), 1 × 10⁹ (BN3), and 1 × 10¹⁰ (BN4) CFU kg⁻¹ for 56 days. Fish in the BN3 and BN4 groups exhibited significantly enhanced growth performance compared to the BN0 group (p < 0.05). Additionally, the activities of amylase and protease were markedly higher in the BN3 and BN4 groups (p < 0.05), while lipase activity was significantly elevated in fish fed the BN3 diet (p < 0.05). Plasma total protein levels also showed a significant increase in the BN3 group (p < 0.05). Hematocrit values were significantly improved in the BN2, BN3, and BN4 groups (p < 0.05). The intestinal microbiota of the BN4 group revealed a significant increase in the populations of B. subtilis and Lactobacillus, along with a notable decrease in Escherichia coli, compared to all other groups (p < 0.05). The observed improvements in specific growth rate and the upregulation of growth-related gene expression further highlight the potential of BSN to enhance the growth performance of red sea bream. In conclusion, dietary supplementation with BSN at 1 × 10⁹ and 1 × 10¹⁰ CFU kg⁻¹ shows promise in improving the growth, health, and immune response of red sea bream.

In this work, we have synthesized copper nanoforms (Cu NFs) using ascorbic acid as a reducing agent and polyvinylpyrrolidone as a stabilizer. Elemental characterization using EDS has shown the nanostructure to be of high purity and compare well with commercially sourced nanoforms. SEM images of both Cu NFs show some agglomeration. The in-house NFs had a better even distribution and size of the nanostructures. The XRD peaks represented a face-centered cubic structure of Cu₂O. The commercially sourced Cu NFs were found to be a mixture of Cu and Cu₂O. Both forms had a crystalline structure. Using these two types of Cu NFs, an antimicrobial study against Colletotrichum gloeosporioides, a devastating plant pathogen, showed the in-house Cu NFs to be most effective at inhibiting growth of the pathogen. Interestingly, at low concentrations, both Cu NFs increased fungal growth, although the mycelia appeared thin and less dense than in the control. SEM macrographs showed that the in-house Cu NFs inhibited the fungus by flattening the mycelia and busting some of them. In contrast, the mycelia were short and appeared clustered when exposed to commercial Cu NFs. The difference in effect was related to the size and/or oxidation state of the Cu NFs. Furthermore, the fungus produced a defense mechanism in response to the NFs. The fungus produced melanin, with the degree of melanization directly corresponding to the concentration of the Cu NFs. Localization of aggregated Cu NFs could be clearly observed outside of the model membranes. The large agglomerates may only contribute indirectly by a hit-and-bounce-off effect, while small structures may adhere to the membrane surface and/or internalize. Spatio-temporal membrane dynamics were captured in real time. The dominant dynamics culminated into large fluctuations. Some of the large fluctuations resulted in vesicular transformation. The major transformation was exo-bud/exo-cytosis, which may be a way to excrete the foreign object (Cu NFs).

To address the challenge of depleting traditional feed resources, this study aimed to biovalorize sweet potato waste (SPW), a major byproduct of the Japanese shochu industry, into a high-value functional animal feed. An innovative two-stage solid-state fermentation (SSF) was employed, featuring an initial aerobic stage with Aspergillus oryzae for substrate degradation, followed by an anaerobic stage with Lactobacillus plantarum for nutritional enhancement. To optimize this complex, multi-variable process, the predictive performance of Artificial Neural Network (ANN) and Random Forest (RF) machine learning models was compared based on an augmented experimental dataset (N = 80). To ensure statistical robustness and prevent data leakage, a repeated k-fold cross-validation strategy was implemented. The RF model demonstrated significantly superior accuracy and reliability than the ANN model, particularly in predicting the primary metric, crude protein (R² = 0.61 ± 0.04 vs. R² = 0.12 ± 0.15). Subsequently, the validated RF model was integrated with a Constrained Differential Evolution (CDE) algorithm for global parameter optimization. The optimized process was predicted to yield a final product with a crude protein content of 25.0%, alongside significant increases of 114.1% in total amino acids and 123.9% in essential amino acids. These projections were experimentally validated in vitro, confirming the model’s accuracy with a relative error of less than 5%. Furthermore, comprehensive biochemical assays demonstrated a massive degradation of anti-nutritional factors and significant enhancements in total phenolic content and antioxidant activity. This study provides a scientifically validated, data-driven framework for the valorization of SPW. It confirms the superior efficacy of ensemble learning methods for optimizing complex bioprocesses with limited data, offering a contribution to the development of a circular bioeconomy and sustainable feed resources.

Enzymatically derived non-starch polysaccharide hydrolysis products (HP) may modulate enteric health outcomes in piglets. Thus, responses of weaned piglets to an oral challenge with enterotoxigenic Escherichia coli F4 (ETEC) when fed diets containing canola meal (CM) HP were investigated. The HP were obtained by incubating CM with a multi-carbohydrase (MC) blend. Thirty-five weaned piglets (8.08 ± 0.34 Kg BW) were individually assigned in a completely randomized design to 1 of 5 treatments: UCC (unchallenged control), NC (negative control challenged with ETEC), PC (NC + 0.1% AGP), HP1 (NC + 0.25% HP), HP2 (NC + 0.5% HP). After a seven-day adaptation period, piglets in the UCC group received 5 ml of PBS, whereas those in all other groups were orally challenged with 5 ml (5 × 10⁶ CFU/mL) of ETEC F4. On d 14 all piglets were euthanized for tissue sampling. Data were analyzed using the PROC MIXED procedure of SAS 9.4, with the individual pig as the experimental unit. During the post-challenge period, piglets fed NC diet had lower (P < 0.05) G: F than those fed the PC, whereas the G: F was higher (P < 0.05) for piglets fed the HP-containing diets than that of piglets fed the NC diet. Piglets fed diets containing HP showed lower (P < 0.05) jejunum pH and fecal scores than piglets fed the NC diet. For gene expressions, the HP groups showed a greater level of toll like receptor 2 (TLR2) compared with NC group (P < 0.05). For the HP groups, HP1 had a higher (P < 0.05) level of TLR2 than HP2 treatment. Feeding HP resulted in lower relative abundance of Bifidobacterium in the colon of piglets compared with feeding with NC (P < 0.05). In conclusion, piglets fed diets with CM HP exhibited less severe ETEC-enteritis and had similar effects with AGP.