Role of ligninolytic enzymes of white rot fungi (Pleurotus spp.) grown with azo dyes.

BACKGROUND: Total three Pleurotus species (P. ostreatus, P. sapidus, P. florida) was compared for ligninolytic enzyme production grown with Coralene Golden Yellow, Coralene Navy Blue and Coralene Dark Red azo dyes in liquid medium under shaking condition. RESULTS: The biodegradation competency varied from species to species and it was found that P. ostreatus, P. sapidus and P. florida to 20 ppm dye concentration shows 88, 92 and 98 % decolorization, respectively for all three dyes. Production pattern of laccase, manganese dependent peroxidase and lignin peroxidase were studied during the growth of the organisms for 10 days. Laccase was found to be the major extracellular ligninolytic enzyme produced by fungus with negligible detection of lignin peroxidases. In all concentration of three dye studied, maximum laccase activity was observed on day 8, for 20 mg/l of dye laccase specific activity was 1-1.58 U/mg in P. ostreatus, 0.5-0.78 U/mg in P. sapidus and 1-1.92 U/mg in P. florida. Different factors (dye concentration, pH, protein and sugar estimation) influencing the ability of Pleurotus species to degrade dyes is documented and degradation was attributed to microbial action irrespective of pH change. HPTLC analysis of samples indicated degradation of dyes into intermediate products. CONCLUSION: Level of ligninolytic enzymes is playing a major role in degradation of dye, which is dependent on time of incubation and species of fungi.

Medicinal and antimicrobial role of the oyster culinary-medicinal mushroom Pleurotus ostreatus (higher Basidiomycetes) cultivated on banana agrowastes in India.

Oyster mushrooms, species of the genus Pleurotus, are recognized for producing secondary metabolites with important medicinal properties. Investigations were carried out to evaluate the antioxidative and antimicrobial properties of the edible mushroom Pleurotus ostreatus (MTCC142) extracts cultivated on banana agrowastes. Ethanolic extracts showed antimicrobial activities against gram-positive and gram-negative bacteria, and their in vitro antifungal activities against all fungi tested revealed a promising role. Qualitative phytochemical analysis of Pleurotus grown on yeast dextrose broth and banana agrowaste confirmed the presence of steroids, cardiac glycosides, terpenoids, and alkaloids, whereas ethanolic extract after 40 days exhibited a phenol concentration of 521.67 µg/mL in banana waste compared to 155 µg/mL in yeast dextrose broth. The minimum inhibitory concentration of ethanolic extracts ranged from 19.74 to 56.84 mg/mL and 35.53 to 102.31 mg/mL in solid-state and submerged grown mycelium extracts, respectively, after 40 days. Moreover, banana agrowaste could be a significant economic source for the production of the oyster mushroom P. ostreatus. The nutritive, medicinal, and antimicrobial properties of P. ostreatus can be used to develop a new nutraceutical formulation; it can also be used as an additive to routine and fast food.

Isolation and partial purification of erythromycin from alkaliphilic Streptomyces werraensis isolated from Rajkot, India.

An alkaliphilic actinomycete, BCI-1, was isolated from soil samples collected from Saurashtra University campus, Gujarat. Isolated strain was identified as Streptomyces werraensis based on morphological, biochemical and phylogenetic analysis. Maximum antibiotic production was obtained in media containing sucrose 2%, Yeast extract 1.5%, and NaCl 2.5% at pH 9.0 for 7 days at 30 °C. Maximum inhibitory compound was produced at pH 9 and at 30 °C. FTIR revealed imine, amine, alkane (C[bond, double bond]C) of aromatic ring and p-di substituted benzene, whereas HPLC analysis of partially purified compound and library search confirmed 95% peaks matches with erythromycin. Chloroform extracted isolated compound showed MIC values 1 µg/ml against Bacillus subtilis, ≤0.5 µg/ml against Staphylococcus aureus, ≤0.5 µg/ml against Escherichia coli and 2.0 µg/ml against Serretia GSD2 sp., which is more effective in comparison to ehtylacetate and methanol extracted compounds. The study holds significance as only few alkaliphilic actinomycetes have been explored for their antimicrobial potential.