Production of kojic acid by Aspergillus flavus OL314748 using box-Behnken statistical design and its antibacterial and anticancer applications using molecular docking technique

Kojic acid is a wonderful fungal secondary metabolite that has several applications in the food, medical, and agriculture sectors. Many human diseases become resistant to normal antibiotics and normal treatments. We need to search for alternative treatment sources and understand their mode of action. Aspergillus flavus ASU45 (OL314748) was isolated from the caraway rhizosphere as a non-aflatoxin producer and identified genetically using 18S rRNA gene sequencing. After applying the Box-Behnken statistical design to maximize KA production, the production raised from 39.96 to 81.59 g/l utilizing (g/l) glucose 150, yeast extract 5, KH2PO4 1, MgSO4.7H2O 2, and medium pH 3 with a coefficient (R2) of 98.45%. Extracted KA was characterized using FTIR, XRD, and a scanning electron microscope. Crystalized KA was an effective antibacterial agent against six human pathogenic bacteria (Bacillus cereus, Staphylococcus aureus, Escherichia coli, Klebsiella pneumonia, Serratia marcescens, and Serratia plymuthica). KA achieves high inhibition activity against Bacillus cereus, K. pneumonia, and S. plymuthica at 100 μg/ml concentration by 2.75, 2.85, and 2.85 compared with chloramphenicol which gives inhibition zones 1, 1.1, and 1.6, respectively. Crystalized KA had anticancer activity versus three types of cancer cell lines (Mcf-7, HepG2, and Huh7) and demonstrated high cytotoxic capabilities on HepG-2 cells that propose strong antitumor potent of KA versus hepatocellular carcinoma. The antibacterial and anticancer modes of action were illustrated using the molecular docking technique. Crystalized kojic acid from a biological source represented a promising microbial metabolite that could be utilized as an alternative antibacterial and anticancer agent effectively.

Exploring the antibacterial potential of plant extracts and essential oils against Bacillus thermophilus in beet sugar for enhanced sucrose retention: a comparative assessment and implications

Sugar beet is one of the greatest sources for producing sugar worldwide. However, a group of bacteria grows on beets during the storage process, leading to a reduction in sucrose yield. Our study focused on identifying common bacterial species that grow on beets during manufacturing and contribute to sucrose loss. The ultimate goal was to find a potential antibacterial agent from various plant extracts and oils to inhibit the growth of these harmful bacteria and reduce sucrose losses. The screening of bacterial species that grow on beet revealed that a large group of mesophilic bacteria, such as Bacillus subtilis, Leuconostoc mesenteroides, Pseudomonas fluorescens, Escherichia coli, Acinetobacter baumannii, Staphylococcus xylosus, Enterobacter amnigenus, and Aeromonas species, in addition to a dominant thermophilic species called Bacillus thermophilus, were found to be present during the manufacturing of beets. The application of 20 plant extracts and 13 different oils indicated that the extracts of Geranium gruinum, Datura stramonium, and Mentha spicata were the best antibacterials to reduce the growth of B. thermophilus with inhibition zones equal to 40, 39, and 35 mm, respectively. In contrast, the best active oils for inhibiting the growth of B. thermophilus were Mentha spicata and Ocimum bacilicum, with an inhibitory effect of 50 and 45 mm, respectively. RAPD-PCR with different primers indicated that treating sugar juice with the most effective oils against bacteria resulted in new recombinant microorganisms, confirming their roles as strong antibacterial products. The characterization of Mentha spicata and Ocimum bacilicum oils using GC/MS analysis identified cis-iso pulegone and hexadecanoic acid as the two main bioactive compounds with potential antibacterial activity. An analysis of five genes using DD-PCR that have been affected due to antibacterial activity from the highly effective oil from Mentha spicata concluded that all belonged to the family of protein defense. Our findings indicate that the application of these pure antibacterial plant extracts and oils would minimize the reduction of sucrose during sugar production.

Isolation and Identification of Fungi from Egyptian Ras Cheese Made with some Probiotic Lactobacillus spp. with Reference to Their Toxins and Enzymes.. [DOI: 10.21203/rs.3.rs-1453816/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Isolation and identification of spoiled fungal species in Ras cheese made by adding probiotic Lactobacillus spp. as adjunct culture were investigated in fresh and 90 days stored samples. Aspergillus flavus and Aspergillus niger were the most predominant spices and have the highest percentages, while they showed lower percentages in the treated cheese samples. However cheese samples were completely free of mycotoxins, A. flavus spices had the ability to produce aflatoxin B1 and G1, and A. niger had the ability to produce Ochratoxin A. All tested A. flavus and A. niger isolates (28) had the ability to produce lipase and protease enzymes; from which 17 and 9 isolates possessed high activities, respectively. The results suggest that incorporation of probiotic bacteria in the manufacture of Ras cheese reduced the fungal growth in cheese, however, some isolated species considered dangerous because its production of toxins and enzymes in proportions affecting the product.

AMEDMENT STABLE KOJIC ACID PRODUCED BY NON-TOXINOGENIC ASPERGILLUS ORYZAE USING FIVE LEVELS CENTRAL COMPOSITE DESIGN OF RESPONSE SURFACE METHODOLOGY

Kojic acid is a remarkable secondary metabolite of Aspergillus with various hot spot applications in the field of medicine, cosmetics, food, agriculture, and chemistry field. However the needs of stable large production with safe cultures still need continuous searching. Microbial kojic acid concentrated highly on Aspergillus species especially Aspergillus flavus group. Ten isolates of A. flavus and A. oryzae isolated from various Egyptian sources were producible of KA in range 0.091±0.01 to 66.81± 0.95 g/l. Aspergillus oryzae (no. 4) that give maximum production was selected as non-toxinogenic safe isolate for optimizing the production by five levels CCD design of RSM. Maximum value of kojic acid with 108.4% increasing was 139.24 g/L (predicted 135.8 g/L) using glucose (+1; 200 g/l), yeast extract (+1; 6 g/l), KH2PO4, (+1; 1.5 g/l) and MgSO4.7H2O (+1; 1 g/l) through run (24). Model significance and validity tested by R2 values of KA was 0.987, DM 0.989 and CS 0.9831 and calculated with Derringer’s desirability function as 0.937. Optimized kojic acid showed stability against different range of heat stress from 40°C to 100°C during five continuous hours which may attribute that microbial product usually more stable than synthetic ones by attaching it with other active groups that guaranty more stability under stress conditions. Aspergillus oryzae (Ao-4) represents promising safe isolate for industrial kojic acid production with highly product stability using this significant valid experimental design.

Enhancement of β-Glucan Biological Activity Using a Modified Acid-Base Extraction Method from Saccharomyces cerevisiae

Beta glucan (β-glucan) has promising bioactive properties. Consequently, the use of β-glucan as a food additive is favored with the dual-purpose potential of increasing the fiber content of food products and enhancing their health properties. Our aim was to evaluate the biological activity of β-glucan (antimicrobial, antitoxic, immunostimulatory, and anticancer) extracted from Saccharomyces cerevisiae using a modified acid-base extraction method. The results demonstrated that a modified acid-base extraction method gives a higher biological efficacy of β-glucan than in the water extraction method. Using 0.5 mg dry weight of acid-base extracted β-glucan (AB extracted) not only succeeded in removing 100% of aflatoxins, but also had a promising antimicrobial activity against multidrug-resistant bacteria, fungi, and yeast, with minimum inhibitory concentrations (MIC) of 0.39 and 0.19 mg/mL in the case of resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa, respectively. In addition, AB extract exhibited a positive immunomodulatory effect, mediated through the high induction of TNFα, IL-6, IFN-γ, and IL-2. Moreover, AB extract showed a greater anticancer effect against A549, MDA-MB-232, and HepG-2 cells compared to WI-38 cells, at high concentrations. By studying the cell death mechanism using flow-cytometry, AB extract was shown to induce apoptotic cell death at higher concentrations, as in the case of MDA-MB-231 and HePG-2 cells. In conclusion, the use of a modified AB for β-glucan from Saccharomyces cerevisiae exerted a promising antimicrobial, immunomodulatory efficacy, and anti-cancer potential. Future research should focus on evaluating β-glucan in various biological systems and elucidating the underlying mechanism of action.

2-Aminoethanaminium 2-(ethoxycarbonyl)-4,6-dinitrophenolate as a greener route in reducing sugar quantification

3,5-dinitrosalicylic acid (DNS) reducing sugar assay is the most convenient method for quantification of total reducing sugar in biomass hydrolysate, fermentation samples, sugar industry and biotechnology laboratories. The dimeric proton transfer salt 2-aminoethanaminium 2-(ethoxycarbonyl)-4,6-dinitrophenolate (AED) is an intensely colored derivative of DNS and in turn its reduced form intense color showed a superior properties in reducing sugar quantification eliminating phenol and rochelle salt additives using the same practical methodology of DNS giving an overall methodology advantageous than using DNS assay as a greener route. The proton transfer salt has already been X-ray imaged and deposited in Cambridge Crystallographic Data Centre CCDC 1441586 and a comparison was done between DNS and this salt using a salt and sodium hydroxide concentrations as the same as DNS assay as well as the latter phenol-rochelle salt free environment giving correlation coefficient 0.999 and absorptivity nearly two thirds the obtained in case of use DNS assay with added phenol for enhancing absorptivity and rochelle salt for produced color stabilization for the same detection range 0.1-0.5 mg/ml according to Miller procedures. The sensitivity and the reduced form color stability of this proton transfer salt could be interpreted on both of its molecular structure has a double oxidizing groups as well as it has an intense color as compared with DNS and a good reduced form solubility respectively. •DNS in reducing sugar quantification, Miller procedures involving phenol and rochelle salt addition.•AED in reducing sugar quantification as the same detection range as DNS with the elimination of phenol and rochelle salt from the assay.•A greener convenient route in reducing sugar quantification.