i CHARACTERIZATION AND IMMOBILIZATION OF PARTIALLY PURIFIED POLYGALACTURONASE FROM ASPERGILLUS NIGER (SA6) FOR INDUSTRIAL USE

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dc.contributor.authorLAWAL, BUGA MOHAMMED
dc.date.accessioned2014-02-17T10:52:11Z
dc.date.available2014-02-17T10:52:11Z
dc.date.issued2008-05
dc.descriptionDEPARTMENT OF BIOCHEMISTRY FACULTY OF SCIENCE AHMADU BELLO UNIVERSITY, ZARIA NIGERIAen_US
dc.description.abstractABSTRACT Polygalacturonase (PG) was isolated from Aspergillus niger(A. niger) SA6. The enzyme was partially purified and characterized. It was then immobilized by entrapment using calcium alginate. The enzyme showed two bands on SDS-PAGE suggesting the presence of an endo and exo PG with apparent molecular weights of 35KDa and 40KDa respectively. The PG was purified 9 fold with a yield of 0.18 % and a specific activity of 246 mole/min/mg. The KM and Vmax values of the enzyme were 2.74 mg/ml and 0.78mole/min/mg respectively. The optimum temperature and optimum pH of the enzyme were 40oC and 4.5 respectively. The native PG was found to be more stable to temperature changes than to pH changes. Both the Vmax and KM of the native PG increased in the presence of EDTA and the following divalent cations Mg2+,Ca2+ and Mn2+. The increase was more pronounced in the presence of Ca2+ ion. The activation energy (Ea) of native PG was 259.19 Cal/degree/mole. The Dixon Plot of the enzyme gave pKa values of 4.9 and 5.6 suggesting Glutamic acid and histidine at the active site of the enzyme. The apparent KM and Vmax of the immobilized PG were 11.1mg/ml and 1.65 mole/min/mg respectively. The optimum pH and optimum temperature of the immobilized PG were 4.5 and 40oC respectively. Immobilized PG was more resistant to changes in pH than to temperature. The activity of the immobilized PG reduced to 34.56 % and 14.81 % of the initial activity in the second and third catalytic cycles respectively. The half-life of the enzyme at 40oC and the activity lost per minute on thermal storage were 10 minutes and 0.0213 μmole of D- galacturonic acid. These findings present novel information on the physico- chemical characteristics of the native and immobilized Polygalacturonase isolated from a local strain of Aspergillus niger (SA6).en_US
dc.identifier.urihttp://hdl.handle.net/123456789/1726
dc.language.isoenen_US
dc.subjectCHARACTERIZATION,en_US
dc.subjectIMMOBILIZATION,en_US
dc.subjectPARTIALLY,en_US
dc.subjectPURIFIED,en_US
dc.subjectPOLYGALACTURONASE,en_US
dc.subjectASPERGILLUS,en_US
dc.subjectNIGER,en_US
dc.subject(SA6)en_US
dc.subjectINDUSTRIAL,en_US
dc.subjectUSEen_US
dc.titlei CHARACTERIZATION AND IMMOBILIZATION OF PARTIALLY PURIFIED POLYGALACTURONASE FROM ASPERGILLUS NIGER (SA6) FOR INDUSTRIAL USEen_US
dc.typeThesisen_US
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