Bioprotection of Zea mays L. from aflatoxigenic Aspergillus flavus by Loigolactobacillus coryniformis BCH-4

Abstract

Fungal infection causes deterioration, discoloration, and loss of nutritional values of food products. The use of lactic acid bacteria has diverse applications in agriculture to combat pathogens and to improve the nutritional values of cereal grains. The current research evaluated the potential of Loigolactobacillus coryniformis BCH-4 against aflatoxins producing toxigenic Aspergillus flavus strain. The cell free supernatant (CFS) of Loig. coryniformis was used for the protection of Zea mays L. treated with A. flavus. No fungal growth was observed even after seven days. The FT-IR spectrum of untreated (T1: without any treatment) and treated maize grains (T2: MRS broth + A. flavus; T3: CFS + A. flavus) showed variations in peak intensities of functional group regions of lipids, proteins, and carbohydrates. Total phenolics, flavonoid contents, and antioxidant activity of T3 were significantly improved in comparison with T1 and T2. Aflatoxins were not found in T3 while observed in T2 (AFB1 and AFB2 = 487 and 16 ng/g each). HPLC analysis of CFS showed the presence of chlorogenic acid, p-coumaric acid, 4-hydroxybenzoic acid, caffeic acid, sinapic acid, salicylic acid, and benzoic acid. The presence of these acids in the CFS of Loig. coryniformis cumulatively increased the antioxidant contents and activity of T3 treated maize grains. Besides, CFS of Loig. coryniformis was passed through various treatments (heat, neutral pH, proteolytic enzymes and catalase), to observe its stability. It suggested that the inhibitory potential of CFS against A. flavus was due to the presence of organic acids, proteinaceous compounds and hydrogen peroxide. Conclusively, Loig. coryniformis BCH-4 could be used as a good bioprotecting agent for Zea mays L. by improving its nutritional and antioxidant contents.

Comprehensive Review of Aflatoxin and Ochratoxin A Dynamics: Emergence, Toxicological Impact, and Advanced Control Strategies

“…Key among the phenolic acids produced by LAB is phenyllactic acid and its derivative, 4-hydroxyphenylactic acid, recognized for their contribution to the antifungal activity of LAB-fermented media, thereby enhancing food shelf life [ 254 , 256 ]. Other phenolic acids generated during LAB fermentation include succinic acid, 4-hydroxybenzoic acid, vanillic acid, caffeic acid, p-coumaric acid, salicylic acid, ferulic acid, and benzoic acid [ 257 ].…”

“…In recent years, oregano, cinnamon, thyme, rosemary, fennel, clove, and eucalyptus have emerged as the most utilized EOs in combatting mycotoxigenic fungi and their associated mycotoxins. The inhibitory effects of EOs on fungal growth and mycotoxin synthesis have been elucidated through various mechanisms, including modification of fungal growth rates and extension of lag phases, disruption of cell permeability, and modulation of gene expression patterns and metabolic processes linked to the electron transport chain [ 257 ].…”

Agonistic antibacterial potential of Loigolactobacillus coryniformis BCH-4 metabolites against selected human pathogenic bacteria: An in vitro and in silico approach

“…Six litres of MRS broth medium (pH 6.4 ± 0.2) were seeded with fresh Loig . coryniformis BCH-4 culture (10% v/v) in the fermenter (BioFer-010, ICCC, Pakistan) at optimized conditions of 37 °C for 72 h under constant stirring of 120 rpm [ 18 ]. After incubation, the culture was centrifuged at 4,430 × g (Z326K, Hermle, Germany) for 10 min at 4 °C and subsequently filtered through 0.22 μm pore size filters (Advantec MFS, Inc., Japan).…”

“…Moreover, biosynthetic abilities of LAB are not only limited to vitamins and amino acids synthesis [13]. They also produce various types of bioactive metabolites like organic acids, exopolysaccharides, bacteriocins, cyclic dipeptides, fatty acids, and phenolics [14][15][16][17][18]. These metabolites exhibit antibacterial potential against gram-positive and gram-negative pathogenic bacteria e.g., S. aureus, Listeria innocua, E. coli, and Hafnia alvei [19,20].…”

Maize hydroxycinnamic acids: unveiling their role in stress resilience and human health

“…The accumulation of HCAAs also improves the resistance of maize to multiple pathogens, including fungi such as Aspergillus flavus (36,37) and Fusarium (38), as well as herbivores including Spodoptera littoralis (39), and the aforementioned insects.…”