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Fungal infection has become a major threat to crop loss and affects food safety. The waste water from agar processing industries extraction has a number of active substances, which could be further transformed by microorganisms to synthesize antifungal active substances. In this study, Bacillus subtilis was used to ferment the waste water from agar processing industries extraction to analyze the antifungal activity of the fermentation broth on Alternaria alternata and Alternaria spp. Results showed that 25% of the fermentation broth was the most effective in inhibited A. alternata and Alternaria spp., with fungal inhibition rates of 99.9% and 96.1%, respectively, and a minimum inhibitory concentration (MIC) was 0.156 μg/mL. Metabolomic analysis showed that flavonoid polyphenols such as coniferyl aldehyde, glycycoumarin, glycitin, and procyanidin A1 may enhance the inhibitory activity against the two pathogenic fungal strains. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that polyphenols involved in the biosynthesis pathways of isoflavonoid and phenylpropanoid were upregulated after fermentation. The laser confocal microscopy analyses and cell conductivity showed that the cytoplasm of fungi treated with fermentation broth was destroyed. This study provides a research basis for the development of new natural antifungal agents and rational use of seaweed agar waste. Key points: • Bacillus subtilis fermented waste water has antifungal activity • Bacillus subtilis could transform active substances in waste water • Waste water is a potential raw material for producing antifungal agents [ABSTRACT FROM AUTHOR]

The present study aims to evaluate the deodorization of Bangiafusco‐purpurea using microorganism fermentation with commercial starter cultures of Saccharomyces cerevisiae, Acetobacter pasteurianus, and Lactobacillus plantarum. The results showed the fermentation with S. cerevisiae, A. pasteurianus, and L. plantarum resulted in significantly decreases (p <.05) of the fishy malodor in B. fusco‐purpurea. Among the three strains, S. cerevisiae was the best for reducing the fishy malodor. The optimal inoculum size and fermentation time were 0.2% and 4 hr, respectively. After the fermentation with the S. cerevisiae, the content of 1‐octen‐3‐ol, (E)‐2‐octen‐1‐ol, hexanal, non‐(2E)‐enal, (E,E)‐2,4‐decadienal, 3,5‐octadien‐2‐one, and 2‐pentyl‐furan were hard to be detected in the seaweed, whereas increases were observed in the concentrations of 2‐butyl‐1‐octanol, cedrol, diisobutyl phthalate, and 2,4‐di‐t‐butylphenol. The odor active value analysis indicated the removal of fishy odor was related to the reduction, dehydrogenation, and deformylating oxygenation of hexanal, nonanal, non‐(2E)‐enal, and (E,E)‐2,4‐decadienal and esterification of 1‐octen‐3‐ol and (E)‐2‐octen‐1‐ol. Our findings provide a technical and scientific basis for the removal of fishy odor from B. fusco‐purpurea. Practical applications: Bangia fusco‐purpurea is a seaweed that can reduce the risks of cardiovascular and chronic metabolic diseases in human body. However, the seaweed has a strong fishy malodor, which largely declines consumer's acceptance. In this study, the commercial starters of Saccharomyces cerevisiae, Acetobacter pasteurianus, and Lactobacillus plantarum were shown to reduce the fishy malodor in B. fusco‐purpurea via fermentation. After the fermentation with the microorganisms especially with the S. cerevisiae, the fishy malodor significantly reduced, and the overall aroma acceptance of B. fusco‐purpurea products greatly improved. Therefore, this study provides a technical basis for the removal of fishy odor from B. fusco‐purpurea and processing value‐added products from it and facilitating its health benefits for human. [ABSTRACT FROM AUTHOR]

Anaerobic fermentation of carrageenan residues for the production of antifungal active compounds and their use to inhibit the growth of phytopathogenic bacteria is a novel approach to the utilization of carrageenan residues. In the present study, the treatment of carrageenan residue by anaerobic biofermentation technique showed strong growth inhibitory activity against Fusarium graminearum and Magnaporthe oryzae , which are the typical phytopathogens that reduce the crop yield, with MIC values of 0.0016% (v/v) and 0.00032% (v/v), respectively. The total concentration of polyphenols and flavonoids increased significantly to 20.41 μg/mL and 29.97 μg/mL after anaerobic fermentation. Amino acid metabolic pathway analysis showed that the substances and energy used by colonies to produce antifungal drugs are derived from amino acid metabolism, especially alanine and γ-aminobutyric acid (GABA). The results of redundancy analysis (RDA) indicated that anaerobic fermentation of carrageenan gum residues increased the abundance of specific bacterial groups included Bacillus, Komona, Caproiciproducens, Lactobacillus, Bovibacillus, and SN8, and that the increase in the number of these species favored the production of polyphenols and flavonoids with antifungal activity. This study provides a viable avenue for resource utilization of carrageenan residues. [Display omitted] • Anaerobic fermentation of carrageenan residues has antifungal activity. • Fermentation significantly increased total polyphenols and flavonoid contents. • Anaerobic fermentation of carrageenan residues increased the abundance of bacteria. • Increase of the species favored polyphenols and flavonoids with antifungal activity. • Carrageenan residues are potential materials for producing antifungal ingredients. [ABSTRACT FROM AUTHOR]

Polysaccharide extracted from red seaweed Bangia fusco-purpurea (BFP) is a novel sulfated galactan, differed from agarans and carrageenans in fine structure. In this study, in vitro fermentation characteristics of BFP by human gut microbiota and its protective effect on lipopolysaccharide (LPS)-induced injury in Caco-2 cells were investigated. Our results showed that BFP was mainly degraded at transverse colon for 18 h fermentation by gut microbiota with reduced molecular weight. Meanwhile, BFP fermentation was associated with increased short-chain fatty acids (SCFAs) as compared to control group, especially acetic acid was increased to 129.53 ± 0.24 from 82.14 ± 0.23 mmol/L, and butyric acid was up to 1.56 ± 0.004 from 0.62 ± 0.01 mmol/L. Furthermore, BFP promoted abundances of Bacteroidetes and Firmicutes , while decreased numbers of Proteobacteria. The up-regrated beneficial differential metabolites were SCFAs, L-proline, arginine, folic acid, pyridoxamine, thiamine, etc. (p < 0.05), and their related metabolic pathways mainly included mTOR, arginine biosynthesis, and vitamin metabolism. Notably, BFP fermentation products at transverse colon significantly restored cell viability of LPS-treated Caco-2 cells from 73.79 ± 0.48 % to 93.79–99.64 %, which might be caused by increased beneficial differential metabolites (e.g. , SCFAs). Our findings suggest that BFP has prebiotic potential and can enhance gut health. • In vitro gut fermentation of Bangia fusco-purpurea polysaccharide (BFP) was explored. • BFP was mainly degraded at transverse colon by gut microbiota. • BFP significantly altered the composition and diversity of gut microbiota. • BFP significantly enhanced the production of SCFAs and beneficial metabolites. • Fermented products of BFP attenuated LPS-induced injury in Caco-2 cells. [ABSTRACT FROM AUTHOR]

Red seaweed contains abundant bioactive ingredients with health benefits. Fermentation is widely used in improving the bioactive ingredients of seaweed materials. However, the types of the active metabolite and changes in biological activity components by the fermentation process remain unknown. In this study, red seaweed Bangia fusco-purpurea was inoculated with Lactobacillus delbrueckii and Lactobacillus plantarum to study bioactive components in supernatants. Results showed that Lactobacillus -fermentation dramatically increased free essential amino acid, trace mineral elements, flavonoids, and polyphenols contents, while decreasing protein and sugar in supernatants. Meanwhile, inhibitions of pancreatic lipase enzyme activities and antibacterial activities against oral pathogenic bacteria were significantly increased by Lactobacillus -fermentation, up to 93.48% and 98.2%, respectively. It might be caused by the increase of polyphenols and flavonoids contents in fermentation supernatants. Also, the biological functions of L. delbrueckii -fermentation were better than that of L. plantarum. Overall, B. fusco-purpurea with Lactobacillus -fermentation has the potential to be special dietary food for improving hyperlipidemia and obesity. [Display omitted] • B. fusco-purpurea was inoculated with Lactobacillus to study bioactive components. • Lactobacillus -fermentation increased polyphenols, essential amino acid and minerals. • Inhibition of pancreatic lipase activity and antibacterial activity were increased. • Fermentation of B. fusco-purpurea is special dietary for hyperlipidaemia and obesity. [ABSTRACT FROM AUTHOR]