Characterization of a novel strain of Aspergillus aculeatinus: From rhamnogalacturonan type I pectin degradation to improvement of fruit juice filtration.

Aspergillus spp. are well-known producers of pectinases commonly used in the industry. Aspergillus aculeatinus is a recently identified species but poorly characterized.

Three novel rhamnogalacturonan I- pectins degrading enzymes from Aspergillus aculeatinus: Biochemical characterization and application potential.

Rhamnogalaturonans I (RGI) pectins, which are a major component of the plant primary cell wall, can be recalcitrant to digestion by commercial enzymatic cocktails, in particular during fruit juice clarification process. To overcome these problems and get better insights into RGI degradation, three RGI degrading enzymes (RHG: Endo-rhamnogalacturonase; ABF: α-Arabinofuranosidases; GAN: Endo-β-1,4-galactanase) from Aspergillus aculeatinus were expressed in Pichia pastoris, purified and fully biochemically characterized. All three enzymes showed acidic pH optimum, and temperature optima between 40-50 °C.

A facile and stereocontrolled synthesis of γ-substituted γ-fluoroglutamates by conjugate addition: conflicting effect between fluorinated enaminoester and hinderered Michael acceptor.

Asymmetric Michael addition of chiral 2-fluoroenaminoesters derived from (S)-1-phenylethylamine to α-substituted methyl acrylate leads to diastereomeric γ-substituted γ-fluoroglutamate precursors. The tertiary center bearing the amino acid function in its natural configuration is generated with a high level of stereocontrol in contrast to the quaternary carbon center. Diastereomeric γ-substituted γ-fluoroglutamates were efficiently separated and isolated as thioketal derivatives harboring very good enantioselectivity.