SCREENING OF ENDOPHYTIC FUNGI FOR THEIR ABILITY TO PRODUCE EXTRACELLULARCELLULASES
Keywords:Cellulases, endophytes, hydrolysis and enzyme assays
Objective: Screening endophytic isolates from woody perennial medicinal plants of Western Ghats for production of extracellular cellulases
Methods: Endophytes were isolated using normal microbiological methods and their colonization frequency and dominance were calculated using statistical methods. Efficiency of growth on complex cellulosic substrates was evaluated on media supplemented with specific substrates. Enzyme assays with identified endophytic fungi were carried from their secretome.
Forty endophytic fungal isolates were obtained using standard isolation methods from different medicinal plants from a biodiversity hotspot in the Western Ghats region of Karnataka, India. The isolated endophytic fungi were then identified based on their morphological characters. The percentage of dominant endophytes (ð·) was calculated based on the colonization frequency. Among the isolated fungi, F. solani and Talaromyces sp. was found to be highest, at5.5 and 5.6 respectively. Each of the identified fungi grown on CMC and seven among the 40 isolates were found to grow luxuriantly as measured by radial growth. The identities of these fungi were morphologically reconfirmed and were completely carbon drained by growing them on a low nutrient medium. These fungi were later evaluated for their growth on avicel and microcrystalline cellulose. Fusarium solani and Tarlaromyces sp. were significantly better in their growth when compared to other endoophytes tested. Further, the cellulosome complex of enzymes were analysed in the secretome of Fusarium solani and Talaromyces sp. Total filter paper activity of Fusarium solani was found to be FPU/ml, 76 FPU/ml and 70 FPU/ml at 24, 48 and 72 hours respectively. Similarly, Filter paper activity of Talaromyces sp. was found to be 89, 86 and 78 FPU/ml at 24h, 48h and 72h respectively. Endogluconase activity of Fusarium solani was found to be 63 CMCase, 60and 61 CMCase at 24, 48 and 72hours of incubation respectively, which was greater than Talaromyces sp. Similarly, Exogluconase and Beta-glucosidase activities were also found to be high in Talomyces sp. when compared to Fusarium solani at all the time intervals tested.
The results from the present study reveals that Fusarium sSolani and Talaromyces sp.are extremely potent producers of cellulases and can thus be used for eco-friendly and economic hydrolysis of biomass for biofuel purposes.
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