Biotechnological potential of a novel tannase-acyl hydrolase from Aspergillus sydowii using waste coir residue: Aqueous two-phase system and chromatographic techniques

Aspergillus is a large tannase-producing genus able to provide enzymes which hydrolyse condensed tannins in waste coir residues. In this work, a tannase-acyl hydrolase (TAH) obtained from Aspergillus sydowii (SIS 25) was extracted and purified by PEG/citrate aqueous two-phase system (ATPS), biochemically characterized and applied for detannification of green tea. A statistical design (23) was used to evaluate the influence of the variables: molar mass of PEG (1000-6000 g/mol), PEG concentration (20.0-24.0% w/w) and sodium citrate concentration (15-20% w/w) at pH 6.0. ATPS efficiency was confirmed by obtaining two major chromatographic peaks (by size exclusion chromatography on a Superdex-G75 at 215 nm) with a unique peak responsible for the hydrolysis of 44% of the phenolic compounds in green tea. This study is focused on the obtention of a microbial tannase purified by ATPS, with potential for debittering and clarifying fruit juices.