Inhibition of Aspergillus flavus growth and its aflatoxins production using the biocontrol agent Saccharomyces cerevisiae as well as to explore its mode of action was studied. Eight strains of S. cerevisiae strains were able to suppress the growth of A. flavus Z103. The maximum growth inhibition of A. flavus Z103 was obtained by living cells of S. cerevisiae EBF101 and S. cerevisiae 117 with 85 and 83%, respectively. The sporulation inhibition and hyphae deterioration of A. flavus Z103 by S. cerevisiae cells adhesion were observed under SEM; up to 99·8% inhibition of aflatoxins biosynthesis by A. flavus Z103 was resulted when the fungus was treated by autoclaved extracellular crude of S. cerevisiae. Also, the tested strains are potential to produce exo‐chitinase which could be suggested as another mode of action for its antifungal activity. GC‐MS analysis of S. cerevisiae 117 extracellular secondary metabolites revealed the existence of 4‐Hydroxyphenethyl alcohol (46·32%), 4, 4‐Dimethyloxazole (9·14%) and 1,2‐Benzenedicarboxylic acid dioctyl ester (2·8%). Significance and Impact of the Study: The use of Saccharomyces cerevisiae instead of chemical preservatives in fermented food, animal and fish feed and storage cereal grains could encourage the food industry to produce organic food free of chemical additives. Overall, our data suggest the possibility of using S. cerevisiae as an alternative treatment in the food industries to control the dispersion and aflatoxins production by Aspergillus flavus during storage. This method could provide an additional probiotic effect in the digestive tract of consumers after ingestion of the treated food. So, our study clarifies the exact mechanisms responsible for the reduction of the aflatoxin contents by S. cerevisiae

Mycosynthesis of AuNPs by Trichoderma hamatum would provide some useful data for oriented biosynthesis of AuNPs. In addition, the applications of mycosynthesized AuNPs were studied against some pathogenic bacteria. Therefore, the gained results detect that these antimicrobial nanoparticles could be explored as hopeful candidates for a variety of biomedical and pharmaceutical applications. This study should provide a further prudence for the fungal-mediated synthesis of AuNPs.

Aims The present work aims to explore a new oleaginous Fusarium isolate potential to accumulate lipids in its biomass from inexpensive substrates. In addition, impacts of carbon and nitrogen sources and their ratios on lipid production by the interested fungal isolate were also studied. Methods and Results Lipid was assayed by sulfo‐phospho‐vanillin colorimetric method. Among 11 Fusarium isolates obtained on potato dextrose agar from rhizosphereic soils, Fusarium RAS18 was selected as the highest producer that accumulates above 20% lipid. It was identified based on phenotypic characterization and the internal transcribed spacer sequence as Fusarium solani, that was recorded in the GenBank database under the accession number . The optimized lipid yield (34·5%) is obtained using glycerol (35 g l−1) and peptone (1·5 g l−1) as carbon and nitrogen sources respectively. The produced fatty acid methyl esters (biodiesel) is composed of linoleic acid (56·81%), palmitic acid (17·81%), oleic acid (11·81%) and stearic acid (11·12). The unsaturated fatty acids accounted for 69% and this is nearly similar to the plant oils commonly used in biodiesel production. Conclusions These findings suggest the applicability of F. solani RAS18 as a promising strain to accumulate lipids from glycerol as a feedstock for biodiesel production. Significance and Impact of the Study Fusarium solani RAS18 is a new oleaginous fungal isolate that is able to produce lipid (34·5%, g g−1) from glycerol. Glycerol is a cheap substrate and is formed as a byproduct from transesterification process and others industries. Thus, recyclation of glycerol for lipid production by micro‐organisms is an important point of economic view. Direct transesterification of the produced fatty acids indicated its similarity to the plant oil composition used in biodiesel production. So, F. solani RAS18 might be a potential lipid source as a feedstock for biodiesel production.

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Kojic acid is a natural organic acid synthesized during aerobic fermentation of carbohydrates as a secondary metabolite by some species of Aspergillus and has been used commercially in several industrial applications. The current investigation aims to optimize the culture conditions for kojic acid production from starch as a carbon source by the novel isolate Aspergillus oryzae 1034. Seventy-five isolates representing 11 species of Aspergillus were isolated from stored wheat grains and screened for kojic acid biosynthesis. Amongst, A. oryzae 1034 was selected as the most potent kojic acid producer from starch. This strain was subjected to different fermentation conditions to maximize the kojic acid production from starch versus glucose. The results concluded that glucose and starch substrates in concentrations 60 and 80 g/l, respectively were the optima for kojic acid production. The optimum phosphorus concentration was 0.5 and 2.0 g/l KH 2 PO 4 in glucose and starch media, respectively. The maximum kojic acid yield was attained at 28ºC for 11 days of incubation in both glucose and starch media with pH 4.5 and 5.0, respectively. Supplementation of Pb +2 to glucose medium and Zn +2 to starch medium stimulated the biosynthesis of kojic acid to 79.3 and 68.8 g/l, respectively. Alternatively, kojic acid biosynthesis was decreased by supplementation of amino acids in the fermentation medium. These findings suggest the possibility of using A. oryzae 1034 as a promising.