title: Production and partial purification of tannase from Aspergillus ficuum Gim 3.6.
abstract: A novel fungal strain, Aspergillus ficuum Gim 3.6, was evaluated for its tannase-producing capability in a wheat bran-based solid-state fermentation. Thin-layer chromatography (TLC) analysis revealed that the strain was able to degrade tannic acid to gallic acid and pyrogallol during the fermentation process. Quantitation of enzyme activity demonstrated that this strain was capable of producing a relatively high yield of extracellular tannase. Single-factor optimization of process parameters resulted in high yield of tannase after 60 hr of incubation at a pH of 5.0 at 30°C, 1 mL of inoculum size, and 1:1 solid-liquid ratio in the presence of 2.0% (w/v) tannic acid as inducer. The potential of aqueous two-phase extraction (ATPE) for the purification of tannase was investigated. Influence of various parameters such as phase-forming salt, molecular weight of polyethylene glycol (PEG), pH, and stability ratio on tannase partition and purification was studied. In all the systems, the target enzyme was observed to preferentially partition to the PEG-rich top phase, and the best result of purification (2.74-fold) with an enzyme activity recovery of 77.17% was obtained in the system containing 17% (w/w) sodium citrate and 18.18% (w/w) PEG1000, at pH 7.0.
authors.affiliation: a College of Life Science and Technology, Guangxi University , Nanning , China.
authors.forename: Wan-liang
authors.initials: WL
authors.lastname: Ma
authors.forename: Fen-fen
authors.initials: FF
authors.lastname: Zhao
authors.forename: Qin
authors.initials: Q
authors.lastname: Ye
authors.forename: Zhen-xing
authors.initials: ZX
authors.lastname: Hu
authors.forename: Dong
authors.initials: D
authors.lastname: Yan
authors.forename: Jie
authors.initials: J
authors.lastname: Hou
authors.forename: Yang
authors.initials: Y
authors.lastname: Yang
mesh_terms: D001230:Aspergillus / Q000201:enzymology*; D002265:Carboxylic Ester Hydrolases / Q000096:biosynthesis / Q000737:chemistry* / Q000302:isolation & purification*; D005656:Fungal Proteins / Q000096:biosynthesis / Q000737:chemistry* / Q000302:isolation & purification*; D006863:Hydrogen-Ion Concentration
chemical_list: D005656:Fungal Proteins; D002265:Carboxylic Ester Hydrolases; C022711:tannase
keywords: Aspergillus ficuum; aqueous two-phase system; sodium citrate; tannase