Surender SinghAjay Kumar2017-12-152017-12-152016http://krishikosh.egranth.ac.in/handle/1/5810037631t-9531t-9531The conversion of vast quantity of ligno-cellulosic (LC) biomass to bioethanol using cellulases and yeasts has been suggested as an alternate energy source and offers potential to reduce the burden on fast depleting fossil fuel reservoirs. The major bottlenecks in commercial exploitation of LC biofuels are recalcitrant nature of raw material, high cost of enzymes for saccharification and non-availability of cofermenting yeasts. Immobilization of the cellulase enzyme on different nano-materials like magnetic supports has been reported and is known to enhance temperature tolerance and activity besides creating an opportunity for recycling for future use. Immobilization of the cellulase from the Aspergillus niger SH3 and commercial enzyme (Cellic CTec3) on five nanoparticle (Iron oxide, Silicon oxide, Magnesium oxide, Zinc oxide and Silver oxide) were studied by two different methods- physical adsorption and covalent coupling. For covalent coupling method nanoparticles were activated with aminopropyltriethoxysilane (APTES). The enzyme-nanoparticle formulations were screened on the basis of the protein binding, enzymatic activities and immobilization efficiency. Iron oxide-enzyme formulations were found to perform best for both indigenous and commercial enzyme with 60 to 80% immobilization efficiency. Besides better thermo-tolerance, the covalently immobilized showed better catalytic efficiency. The saccharification yields of the free and immobilized enzymes under optimized condition (60˚C temperature, 5.0 pH and 6% substrate loading) were compared for both indigenous and commercial enzyme. The indigenous immobilized enzyme showed more saccharification yield (375.39 mg/gds) than free enzyme (339.99 mg/gds). The commercial (Cellic CTec3) immobilized enzyme showed less sugar yield (314.77 mg/gds) as compared to the free enzyme (366.6 mg/gds). After 2 cycles of saccharification, 55 and 45 % enzyme activities were recovered for indigenous and commercial enzyme respectively. In conclusion, covalently immobilized magnetic enzyme nanoparticle complex showed promise for their use in bioethanol production which can help in economical production of bioethanol from lignocellulosic biomass. Besides bioethanol, the prepared enzyme formulation can be used in textile, detergents and food industries.en-USnullThesis