Biocatalyst Immobilization by Anchor Peptides on an Additively Manufacturable Material

Additive manufacturing refers to manufacturing methods, which are being used to build up three-dimensional (3D) structures by adding a certain material stepwise onto a support. Nowadays, these manufacturing methods can be more material- and cost-efficient compared to conventional methods and allowing the defined production of a wide variety of 3D structures using computer aided design (CAD). A broad range of materials can be additively manufactured (AM) resulting in specific properties and highly diverse structures making them promising matrices for the utilization as enzyme carriers. The variety of materials offers the possibility to select materials with properties needed for particular biocatalytic processes. This is especially true for hybrid reactor concepts where multiple operations, including catalytic reactions and downstream processes, are combined into a single apparatus. For the enzymatic decarboxylation of ferulic acid, polyethylene terephthalate (PET) has been chosen as an additively manufacturable carrier material for the immobilization of phenolic acid decarboxylase (PAD) from Mycobacterium columbiense. The genetic fusion of PAD with anchor peptides enabled the adsorptive immobilization on PET. Starting from an immobilizate activity of 0.39 +/- 0.19 U m(-2) and a conversion of 19.2 +/- 3.7% after 2 h the optimization of the peptide and spacer sequence between anchor peptide and PAD resulted in immobilizates with activities up to 1.80 +/- 0.41 U m(-2) and conversions of 59.9 +/- 3.9% after 2 h. Moreover, within this study integrating an in situ product removal, enabled by an extraction with n-heptane, the altering of surface hydrophobicity of PET and a conversion of 88.0 +/- 3.8% after 2 h could be observed.