PRODUCTION AND OPTIMIZATION OF POLY γ-GLUTAMIC ACID FROM BACILLUS SUBTILIS USING RICE HUSK BY SOLID STATE FERMENTATION

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dc.contributor.authorTITUS, Stephen Dio
dc.date.accessioned2021-11-04T07:55:39Z
dc.date.available2021-11-04T07:55:39Z
dc.date.issued2021-04
dc.descriptionA DISSERTATION SUBMITTED TO THE SCHOOL OF POSTGRADUATE STUDIES, AHMADU BELLO UNIVERSITY, ZARIA IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE AWARD OF MASTER DEGREE IN BIOCHEMISTRY DEPARTMENT OF BIOCHEMISTRY, FACULTY OF LIFE SCIENCES, AHMADU BELLO UNIVERSITY, ZARIA NIGERIAen_US
dc.description.abstractPoly-γ-glutamic acid (γ-PGA) is an anionic polyamino acid composed of L and D glutamic acid isomers linked via amide bond between the α-amino and γ-carboxylic groups of adjacent monomers largely synthesised by microorganisms of the Genus Bacillus. γ-PGA has been explored in the design of scaffolds, nanosystems, adhesives, hydrogels, thickeners and humectants because of its non-toxicity, non-immunogenicity, water solubility and biodegradability. This study was undertaken to optimize the production of γ-PGA from Bacillus subtilis using rice husk by solid state fermentation. Different Bacillus subtilis were isolated from water, soil and Daddawa samples collected in Samaru, Zaria, Nigeria and used for the production of γ-PGA. The isolates were characterised by biochemical and molecular techniques and then subjected to screening and production optimization by central composite design of response surface methodology. Among the 3 isolates (S1, S4 and S5), S5 has a significantly higher yield of 2.5 g/L of γ-PGA, hence was used in solid state fermentation for the optimization and production of γ-PGA using rice husk as the basal media. Exactly eleven (11) media components and process parameters were screened using definitive screening design (DSD) with citric acid, glycerol and 6-diazo-5-oxo-L-norleucine (DON) having the most significant influence on the yield which were optimized by response surface methodology using central composite design (CCD). A maximum production of γ-PGA of 19.55±5.75 mg/g and molecular weights within the range of 35 kDa to 96 kDa bands by SDS-PAGE were obtained when the concentrations of medium components were set at 25 μg/100g DON, 7.5% citric acid and 9.96% glycerol. Hence, B. subtilis isolate S5 is a promising strain for the production of low molecular weight γ-PGA from rice husk via solid state fermentation.en_US
dc.identifier.urihttp://hdl.handle.net/123456789/12701
dc.language.isoenen_US
dc.subjectPRODUCTION,en_US
dc.subjectOPTIMIZATION,en_US
dc.subjectPOLY γ-GLUTAMIC ACID,en_US
dc.subjectBACILLUS SUBTILIS,en_US
dc.subjectRICE HUSK,en_US
dc.subjectSOLID STATE FERMENTATION.en_US
dc.titlePRODUCTION AND OPTIMIZATION OF POLY γ-GLUTAMIC ACID FROM BACILLUS SUBTILIS USING RICE HUSK BY SOLID STATE FERMENTATIONen_US
dc.typeThesisen_US
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