The effect of two species of lactobacilli, Lactobacillus casei CRL 431 and Lactobacillus rhamnosus CRL 1224, on growth of different Aspergillus flavus strains was determined. A. flavus strains (Ap, TR2, or CF80) were grown in LAPTg broth at 37 degrees C for 7 days as a single culture and in association with L. casei CRL 431 or L. rhamnosus CRL 1224 at initial inoculum ratios of 1:1, 1:10, and 1:100. In most cases, the mixed cultures had a lower fungal growth and a lower pH than the control cultures. Mycelial dry weight was reduced to 73 and 85% using L. casei CRL 431 and L. rhamnosus CRL 1224, respectively. The pH decrease in mixed cultures when the fungal mycelial dry weight is reduced may play an important role in inhibition. The number of viable bacteria was variably affected by fungal growth. These results indicate that L. casei CRL 431 and L. rhamnosus CRL 1224 may be useful as potential biocontrol agent against A. flavus.
"It is possible, therefore, that this group of bacteria may be useful in developing targeted strategies for controlling fungi in agricultural systems. Another example of cultural experimentation to identify microbial antagonists of aflatoxigenic fungi is the characterization of the inhibitory activity of two Lactobacillus species against A. flavus (Bueno et al., 2006). Strains of L. casei, isolated from human feces, and L. rhamnosus, isolated from yogurt, both reduced growth of A. flavus strains in liquid co-culture, but not in agar diffusion assays. "
[Show abstract][Hide abstract] ABSTRACT: Mycotoxins such as aflatoxins, fumonisins, trichothecenes, and ochratoxins are contaminants of many agronomic crops worldwide, and cause both economic losses and health effects. The potential of antagonistic microorganisms to be developed into biological control agents has been investigated in several crop systems, as alternatives to chemical fungicides for control of mycotoxigenic fungi. Laboratory and greenhouse studies have identified a number of bacterial, yeast, and filamentous fungal isolates that reduce crop contamination of mycotoxigenic fungi, although investigations of field efficacy have been limited. These studies demonstrate that the diversity of ecological interactions between mycotoxigenic fungi and other resident microorganisms may provide tools for development of biocontrol methods to reduce mycotoxin contamination.
[Show abstract][Hide abstract] ABSTRACT: The cell-free culture filtrate (CCF) was prepared from a culture of an Aspergillus flavus antagonist, Bacillus subtilis B-FS06. The CCF inhibited the growth and spore germination of A.flavus at a series of concentrations (10, 25, 50%) (v/v). It still retained the activity after treatment at pH values ranging from
2 to 12 for 24h or at 100°C for 30min. The antifungal activity, however, was reduced by 30% after treatment at 121°C for
20min. After purification by anion exchange chromatography, gel filtration chromatography and HPLC, the active compounds
revealed six ion peaks: [M–H] m/z=1006.78, 1020.71, 1034.74, 1049.54, 1056.78, and 1071.64 by using electrospray ionization mass spectrometry (ESI-MS) analysis.
In the presence of the active compounds at 200μg/g, the growth of A.flavus on peanuts was completely inhibited.
World Journal of Microbiology and Biotechnology 06/2008; 24(6):783-788. DOI:10.1007/s11274-007-9533-1 · 1.78 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Sugar production from sugarcane generates residual products, currently, many of which are waste products. At the same time, introduction of probiotic bacteria to food animals needs an economical production medium. Fermentation of sugarcane blunting, an industrial residue, inoculated with ruminant probiotic bacteria was investigated. Fermentation was carried out using native flora (NF) alone, NF plus a goat probiotic lactic acid bacterium (LAB), and NF plus goat probiotic co-inoculated with two LAB isolated from sugarcane. Survival of microorganisms and metabolite produce were monitored. In the inoculated samples, pH was lower, dry matter was >30%, and Enterobacteriaceae and fungus decreased when compared to natural fermentation. The LAB inoculated grew and multiplied during fermentation. All beneficial changes were more quickly in the co-inoculated samples. The results presented indicate that sugarcane blunting can be used as a medium for introduction of ruminant probiotic bacteria. Fermentation of blunting can prolong shelf life and increase microbiological safety.
Journal of Bioscience and Bioengineering 10/2008; 106(4):363-7. DOI:10.1263/jbb.106.363 · 1.88 Impact Factor
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