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The aim of this study was to investigate the ligninolytic system of fungal strains isolated from Egyptian agricultural soil which are efficient in biodegradation and mineralization of lignin. They were identified morphologically, microscopically and confirmed by RAPD profiles. Based on PCR amplification and sequencing of the 18S rDNA gene an analytical phylogenetic tree was drawn for species confirmation. The screening experiment revealed that Emericella nidulans, Aspergillus fumigatus, Phoma betae, Penicillium oxalicum and Humicola grisea exhibited maximum potential for high lignin degradation. They showed higher lignin peroxidase and laccase activities. By process optimization, enhanced lignin degradation (94 %) was achieved within 7 days in lignin-glucose medium when compared with lignin degradation (70 %) obtained in glucose-free medium. The ligninolytic enzymatic activities had a great potential for decolorization of chemically different synthetic dyes (Azure B, Safranin, Crystal Violet and Malachite Green). The highest enzymatic activities and the highest decolorization rates were detected at a dye concentration of 0.2 g/L. The dye decolorization rate significantly increased with tryptophan addition as (1 mmol/L). Humicola grisea showed the highest decolorization rate (99 %) with azure B. Phoma beta also showed a high decolorization rate (99 % with crystal violet and 90 % with safranin). The observed activity enhancement resulted from the protective effect of tryptophan against H 2 O 2 inactivation.

In search of a safe and new biosource for treating fungal infections, the bacterial lysate of probiotic Lactobacillus fermentum was tested for its antifungal activity against Aspergillus niger, Aspergillus flavus and Candida albicans. The antifungal activity of lysate was analyzed by dry weight, disc diffusion and micro broth dilution methods. The growth of A. niger and A. flavus was inhibited by 31 µg lysate protein/disc but C. albicans was firstly inhibited at 62 µg lysate protein/disc. MIC for inhibition of A. niger was recorded as 125 µg lysate/ml while, A. flavus and C. albicans were inhibited at MIC of 62 µg lysate/ml by micro broth dilution assay. De Man Rogose and Sharpe medium supplemented with wheat bran, corn steep liquer and yeast extract showed the highest yield, 10 g dry biomass/L of L.fermentum at pH 6.8. The elution profile of the purified lysate showed five fractions, the first gave more than 60% of the original sample. Its MIC was 25 µg lysate/disc. Its molecular weight was 20 to 30 KDa. Toxicity tests revealed that, up to 150 µg lysate/ml showed no significant haemolysis.

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