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20121
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Subject: Microbiology × Author: Agarwal, Monika × End date: 2016 × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    Production and partial purification of fungal cellulase for ethanol production from paddy straw
    (CCSHAU, 2012) Agarwal, Monika; Leela Wati
    Cellulosic ethanol is a biofuel produced from wood, grasses , and the nonedible parts of plants. There is a tremendous search for a biofuel to be used as an alternative source of energy, utilizing the existing lignocellulosic biomolecules and among these, paddy straw is abundant in India. Cellulose is the most abundant carbohydrate polymer in paddy straw. It is commonly degraded by an enzyme called cellulase. This enzyme is produced by several microorganisms commonly by fungi but most of them have high running cost and low efficiency in cellulase production and its enzyme activity. Therefore, in the present investigation, a total of 10 cellulolytic fungal cu ltures (4 mycelial and 6 spore forming) were isolated from different soil samples. All isolates were screened for cellulolytic activity by observing clear zone formation ability on carboxymethylcellulose (CMC) agar plates. Isolate F-1 formed largest clearance zone with diameter 7.0 mm. On studying exoglucanase and endoglucanase activities, isolate F-1 was best among the isolates with 0.42 and 1.26 IU/ml FPase and CMCase activities, respectively while activity of standard culture of Trichoderma reesei MTCC 3194 was 0.48 IU/ml (FPase) and 1.71 IU/ml (C MCase). Cellulase production was maximum in Mandels and Sternberg medium containing delignified paddy straw as carbon source at 30 0 C after 7 days incubation with activity 0.66 IU/ml (FPase) and 2.52 IU/ml (CMCase) for F-1 isolate and 0.76 IU/ml FPase and 2 .76 IU/ml CMCase for MTCC 3194. Partial purification of crude cellulase was done by ammonium sulfate precipitation and best results were at 50-55% ammonium sulfate saturation followed by dialysis in 10 times diluted buffer that resulted in 2.8 and 2.1 folds increase in FPase and CMCase activities, respectively. Conditions for hydrolysis of delignified paddy straw using partially purified enzyme were standardized and best results were observed at 50 0 C for 4 h reaction time with release of 50.5% total reducing sugars and 63.7% sa ccharification for F-1 isolate and 55.5% reducing sugars and 69.7% saccharification for MTCC 3194. Ethanol production from paddy straw hydrolysate obtained after treatment with par tially purified F-1 cellulase inoculated with Saccharomyces cerevisiae HAU-1 at 30 0 C was 2.8% (v/v) after 72 h for F-1 isolate and 3.0% (v/v) for MTCC 3194.