From gene towards selective biomass valorization: bacterial ß-etherases with catalytic activity on lignin-like polymers.

Microbial ß-etherases, which selectively cleave the ß-O-4 aryl ether linkage present in lignin, hold great promise for future applications in lignin valorization. However, very few members have been reported so far and little is known about these enzymes. By using a database mining approach, four novel bacterial ß-etherases were identified, recombinantly produced in Escherichia coli, and investigated together with known ß-etherases in the conversion of various lignin and non-lignin-type model compounds. The resulting activities revealed the significant influence of the substituents at the phenyl ring adjacent to the ether bond. Finally, ß-etherase activity on polymeric substrates, measured by using a fluorescently labeled synthetic lignin, was also proven; this underlined the applicability of the enzymes for the conversion of lignin into renewable chemicals.

Lipase-mediated oxidative delignification in non-aqueous media: formation of de-aromatized lignin-oil and cellulase-accessible polysaccharides.

Pulp & Oil: We report the unprecedented formation of de-aromatized lignin oil together with a white polysaccharide fraction when lignocellulose is treated with peracids, which are formed in situ by enzymes. A preliminary characterization of the lignin oil is provided, together with the evidence that the delignified lignocellulose is accessible to cellulases to afford fermentable sugars. As a first proof-of-concept, the reported approach may bring promising new research lines in the future.

Improving the carboxyamidomethyl ester for subtilisin A-catalysed peptide synthesis.

A series of novel glycine esters was evaluated for efficiency in subtilisin A-CLEA-catalysed peptide synthesis. The reactivity of the easily accessible carboxyamidomethyl (Cam) ester was further enhanced by elongating it with an amino acid residue, thereby creating more recognition space for subtilisin A.