An enzymatic continuous-flow reactor based on a pore-size matching nano- and isoporous block copolymer membrane.

Continuous-flow biocatalysis utilizing immobilized enzymes emerged as a sustainable route for chemical synthesis. However, inadequate biocatalytic efficiency from current flow reactors, caused by non-productive enzyme immobilization or enzyme-carrier mismatches in size, hampers its widespread application. Here, we demonstrate a general-applicable and robust approach for the fabrication of a high-performance enzymatic continuous-flow reactor via integrating well-designed scalable isoporous block copolymer (BCP) membranes as carriers with an oriented and productive immobilization employing material binding peptides (MBP). Densely packed uniform enzyme-matched nanochannels of well-designed BCP membranes endow the desired nanoconfined environments towards a productive immobilized phytase. Tuning nanochannel properties can further regulate the complex reaction process and fortify the catalytic performance. The synergistic design of enzyme-matched carriers and efficient enzyme immobilization empowers an excellent catalytic performance with >1 month operational stability, superior productivity, and a high space-time yield (1.05 × 105 g L-1 d-1) via a single-pass continuous-flow process. The obtained performance makes the designed nano- and isoporous block copolymer membrane reactor highly attractive for industrial applications.

Biadhesive Peptides for Assembling Stainless Steel and Compound Loaded Micro-Containers.

Biadhesive peptides (peptesives) are an attractive tool for assembling two chemically different materials-for example, stainless steel and polycaprolactone (PCL). Stainless steel is used in medical stents and PCL is used as a biodegradable polymer for fabrication of tissue growth scaffolds and drug delivering micro-containers. Biadhesive peptides are composed of two domains (e.g., dermaseptin S1 and LCI) with different material-binding properties that are separated through a stiff peptide-spacer. The peptesive dermaseptin S1-domain Z-LCI immobilizes antibiotic-loaded PCL micro-containers on stainless steel surfaces. Immobilization is visualized by microscopy and field emission scanning electron microscopy analysis and released antibiotic from the micro-containers is confirmed through growth inhibition of Escherichia coli cells.

Ultrahigh-throughput screening system for directed polymer binding peptide evolution.

Accumulation of plastics in the environment became a geological indicator of the Anthropocene era. An effective reduction of long-lasting plastics requires a treatment with micro-organisms that release polymer-degrading enzymes. Polymer binding peptides function as adhesion promoters and enable a targeted binding of whole cells to polymer surfaces. An esterase A-based Escherichia coli cell surface display screening system was developed, that enabled directed evolution of polymer binding peptides for improved binding strength to polymers. The E. coli cell surface screening system facilitates an enrichment of improved binding peptides from a culture broth through immobilization of whole cells on polymer beads. The polypropylene (PP)-binding peptide liquid chromatography peak I (LCI) was simultaneously saturated at five positions (Y29, D31, G35, E42, and D45; 3.2 million variants) and screened for improved PP-binding in the presence of the anionic surfactant sodium dodecylbenzenesulfonate (LAS; 0.25 mM). The cell surface system enabled efficient screening of the generated LCI diversity (in total ~10 million clones were screened). Characterization of identified LCI binders revealed an up to 12-fold improvement (eGFP-LCI-CSD-3: E42V/D45H) in PP-binding strength in the presence of the surfactant LAS (0.125 mM). The latter represents a first whole cell display screening system to improve adhesion peptides which can be used to direct and to immobilize organisms specifically to polymer surfaces (e.g., PP) and novel applications (e.g., in targeted plastic degradation).

Targeting microplastic particles in the void of diluted suspensions.

Accumulation of microplastic in the environment and food chain will be a grand challenge for our society. Polyurethanes are widely used synthetic polymers in medical (e.g. catheters) and industrial products (especially as foams). Polyurethane is not abundant in nature and only a few microbial strains (fungi and bacteria) and enzymes (polyurethaneases and cutinases) have been reported to efficiently degrade polyurethane. Notably, in nature a long period of time (from 50 to >100 years depending on the literature) is required for degradation of plastics. Material binding peptides (e.g. anchor peptides) bind strongly to polymers such as polypropylene, polyethylene terephthalate, and polyurethane and can target specifically polymers. In this study we report the fusion of the anchor peptide Tachystatin A2 to the bacterial cutinase Tcur1278 which accelerated the degradation of polyester-polyurethane nanoparticles by a factor of 6.6 in comparison to wild-type Tcur1278. Additionally, degradation half-lives of polyester-polyurethane nanoparticles were reduced from 41.8 h to 6.2 h (6.7-fold) in a diluted polyester-polyurethane suspension (0.04% w/v).