Chinese yam with damaged outer skin can be easily oxidized and infected by spoilage fungi. To find preservatives in the storage of the Chinese yam, Aspergillus niger 103 was isolated, identified, and determined as the dominant spoilage fungus in Chinese yam according to Kochs postulates. Then, the strain was used as a model to screen antifungal agents and study antifungal mechanisms in this study. We found that cinnamon essential oil was the best antifungal agent, and the minimum concentration against Aspergillus niger 103 was 25μg/mL. The storage life of Chinese yam could significantly extend by 27.66 days by spraying with cinnamon essential oil (25μg/mL). To further explore the antifungal mechanism of cinnamon essential oil against Aspergillus niger 103, alkaline phosphatase activity and electrolyte content in the fungal solution were measured. The alkaline phosphatase activity and electrolyte content of the fungal solution with cinnamon essential oil were significantly increased than those without cinnamon essential oil, which showed that the cinnamon essential oil could destroy the integrity of the cell wall and cell membrane of Aspergillus niger 103, and disrupted cellular homeostasis of Aspergillus niger 103.

Probiotics are a prominent alternative to antibiotics in antimicrobial-free broiler farming. To assess the effect of Sphingomonas sp. Z392 (isolated and identified) on broiler growth, 600 one-day-old Kebao broiler chickens were randomly divided into a control group and an experimental group. Each group had three replicates, with 100 broiler chickens being raised in each replicate. Regarding the experimental group of broiler chickens, 4.0 × 10⁵ CFU/mL of Sphingomonas Z392 was added to their drinking water. Then, the changes in broiler body weight, the EPI, intestinal histological structure, and gut microbiota were examined. The results show that the supplementation of the broilers’ drinking water with 4 × 10⁵ CFU/mL of Sphingomonas Z392 resulted in an increase in the relative abundance of Lactobacillus, Bacteroides, Lachnospiraceae, Aminobacterium, Oribacterium, Christensenellaceae, Faecalibacterium, Barnesiella, Ruminococcus, Parabacteroides, Phascolarctobacterium, Butyricicoccaceae, and Caproiciproducens, which have been reported to be positively correlated with the improved digestion and absorption of broiler chickens. The relative abundance of Odoribacter, Alistipes, Parabacteroides, and Rikenellaceae increased, and these have been reported to be negatively correlated with the occurrence of intestinal diseases. The relative abundance of Campylobacter, Shigella Castellani, Bilophila, Campylobacter, Clostridia, and Anaerotruncus decreased, and these have been reported to be positively correlated with the occurrence of intestinal diseases. At the same time, the following also increased: the integrity of small intestinal villus morphology; the number of goblet cells in small intestinal epithelial cells; the health of the mitochondria in the cytoplasm of jejunal villous epithelial cells; the number of lysosomes in the cytoplasm of goblet cells in the small intestinal epithelium, ileal villous epithelial cells, and mitochondria in the cytoplasm of large intestinal villous epithelial cells; the VH/CD of the ileum; and digestive, absorption, and defense capabilities. In particular, the final weight increased by 4.33%, and the EPI increased by 10.10%. Therefore, the supplementation of broiler drinking water with Sphingomonas generated better economic benefits from the broiler chickens.

Probiotics have emerged as a prominent alternative to antibiotics in antimicrobial-free broiler farming. To assess the effect of the probiotics Sphingomonas sp. Z392 isolated and identified by this this laboratory on broiler growth, we conducted a study to examine the changes in broiler body weight, EPI, intestinal histological structure and gut microbiota. The results showed that supplementation of broiler drinking water with 4 × 105 CFU/mL of Sphingomonas resulted in an increase in the relative abundance of Lactobacillus, Bacteroides, Lachnospiraceae, Aminobacterium, Oribacterium, Christensenellaceae, Faecalibacterium, Barnesiella, Ruminococcus, Parabacteroides, Phascolarctobacterium, Butyricicoccaceae, and Caproiciproducens, which were reported to be positively correlated with the digestion and absorption of broiler chickens. The relative abundance was increased of Odoribacter, Alistipes, Parabacteroides, and Rikenellaceae, which were reported to be negatively correlated with the occurrence of intestinal diseases. The relative abundance was decreased of Campylobacter, Shigella Castellani, Bilophila, Campylobacter, Clostridia, and Anaerotruncus, which were reported positively correlated with the occurrence of intestinal diseases. At the same time, it was increased in the integrity of small intestinal villus morphology, the number of goblet cells in small intestinal epithelial cells, the health of mitochondria in the cytoplasm of jejunal villous epithelial cells, and the number of lysosomes in the cytoplasm of goblet cells in small intestinal epithelium, ileal villous epithelial cells, mitochondria in the cytoplasm of large intestinal villous epithelial cells, the VH/CD of the ileum, digestive, absorption, and defense capabilities. Especially the final weight was increased by 4.33% and the EPI increased by 10.10%. Therefore, the supplementation of broiler drinking water with Sphingomonas generated better economic benefits for the broiler chickens.

Tomato is perishable and requires preservation to extend its shelf life. In this study, we conducted selection processes to identify essential oils that can help to avoid spoilage and deterioration during tomato storage and extend the shelf life. Thereafter, we determined the phosphatase activity assay, potassium ion concentration, and electron microscopy to study the antibacterial mechanism of essential oil. We found that Enterobacter ludwigii W01 was the dominant spoilage bacterium in tomatoes with cracked and curled skin. We selected oregano essential oil from 12 essential oils (oregano essential oil, lemon essential oil, osmanthus essential oil, cypress wood essential oil, tea tree essential oil, licorice essential oil, Baili essential oil, white camphor essential oil, Shancang seed essential oil, rosemary essential oil, rose essential oil, and cinnamon essential oil) which could significantly inhibit the activity of E. ludwigii W01. However, the diameter of the inhibition zone for Wh, Te, Cy, Li, Rm, Le, and Os is 0mm, the diameter of the inhibition zone for Ba, Sh, and Ro was less than 1.0mm, whereas the diameter of the inhibition zone for Ci and Or was greater than 2.0mm. The diameter of the suppression circle for Ci and Or was greater than 2.0mm, while Ci was lesser than Or. Oregano essential oil can damage the cell wall of E. ludwigii W01, leading to the leakage of the alkaline phosphatase stored between the cell wall and the cell membrane which can increase the alkaline phosphatase activity in the bacterial solution. Meanwhile, the addition of oregano essential oil significantly altered the cellular morphology of E. ludwigii W01. Spraying the surface of fresh tomato fruits with 1 MIC (0.125) of oregano essential oil prolonged the storage time to 15 days, without significant changes in its sensory attributes. Those results indicated that oregano essential oil was a potential preservative for tomatoes.

The ncd2-overexpressing Sphingomonas sp. Z392 strain was verified to reduce ammonia levels in our previous study. To ensure its safe utilization, this stud