Detergent-assisted Enhancement of the Translation Rate during Cell-free Synthesis of Peptides in an Escherichia coli Extract

Developing an E. coli-Based Cell-Free Protein Synthesis System for Artificial Spidroin Production and Characterization

Spider silk spidroins, nature's advanced polymers, have long hampered efficient in vitro production due to their considerable size, repetitive sequences, and aggregation-prone nature. This study harnesses the power of a cell-free protein synthesis (CFPS) system, presenting the first successful in vitro production and detailed characterization of recombinant spider silk major ampullate spidroins (MaSps) utilizing a reformulated and optimizedEscherichia coli based CFPS system. Through systematic optimization, including cell strain engineering via knockout generation, energy sources, crowding agents, and amino acid supplementation, we effectively addressed the specific challenges associated with recombinant spidroin biosynthesis, resulting in high yields of 0.61 mg/mL for MaSp1 (69 kDa) and 0.52 mg/mL for MaSp2 (73 kDa). The synthesized spidroins self-assembled into micelles, facilitating efficient purification compared to in vivo methods, and were further processed into prototype silk fiber products. The functional characterization demonstrated that the purified spidroins maintain essential natural properties, such as phase separation and fiber formation triggered by pH and ions. This tailored CFPS platform also facilitates versatile cosynthesis and serves as an accessible platform for studying the supramolecular coassembly and dynamic interactions among spidroins. This CFPS platform offers a viable alternative to conventional in vivo methods, facilitating innovative approaches for silk protein engineering and biomaterial development in a high-throughput, efficient manner.

Cell-free protein synthesis system: A new frontier for sustainable biotechnology-based products

Cell-free protein synthesis (CFPS) system is an innovative technology with a wide range of potential applications that could challenge current thinking and provide solutions to environmental and health issues. CFPS system has been demonstrated to be a successful way of producing biomolecules in a variety of applications, including the biomedical industry. Although there are still obstacles to overcome, its ease of use, versatility, and capacity for integration with other technologies open the door for it to continue serving as a vital instrument in synthetic biology research and industry. In this review, we mainly focus on the cell-free based platform for various product productions. Moreover, the challenges in the bio-therapeutic aspect using cell-free systems and their future prospective for the improvement and sustainability of the cell free systems.

A Multiplexed Cell-Free Assay to Screen for Antimicrobial Peptides in Double Emulsion Droplets

The global surge in bacterial resistance against traditional antibiotics triggered intensive research for novel compounds, with antimicrobial peptides (AMPs) identified as a promising candidate. Automated methods to systematically generate and screen AMPs according to their membrane preference, however, are still lacking. We introduce a novel microfluidic system for the simultaneous cell-free production and screening of AMPs for their membrane specificity. On our device, AMPs are cell-free produced within water-in-oil-in-water double emulsion droplets, generated at high frequency. Within each droplet, the peptides can interact with different classes of co-encapsulated liposomes, generating a membrane-specific fluorescent signal. The double emulsions can be incubated and observed in a hydrodynamic trapping array or analyzed via flow cytometry. Our approach provides a valuable tool for the discovery and development of membrane-active antimicrobials.

Characterizing and Improving Reaction Times for E. coli-Based Cell-Free Protein Synthesis

Cell-free protein synthesis (CFPS) is a platform biotechnology that has enabled the on-demand synthesis of proteins for a variety of applications. Numerous advances have improved the productivity of the CFPS platform to result in high-yielding reactions; however, many applications remain limited due to long reaction times. To overcome this limitation, we first established the benchmarks reaction times for CFPS across in-house E. coli extracts and commercial kits. We then set out to fine-tune our in-house extract systems to improve reaction times. Through the optimization of reaction composition and titration of low-cost additives, we have identified formulations that reduce reaction times by 30-50% to obtain high protein titers for biomanufacturing applications, and reduce times by more than 50% to reach the sfGFP detection limit for applications in education and diagnostics. Under optimum conditions, we report the visible observation of sfGFP signal in less than 10 min. Altogether, these advances enhance the utility of CFPS as a rapid, user-defined platform.

Cell-Free Metabolic Engineering: Recent Developments and Future Prospects

Due to the ongoing crises of fossil fuel depletion, climate change, and environmental pollution, microbial processes are increasingly considered as a potential alternative for cleaner and more efficient production of the diverse chemicals required for modern civilization. However, many issues, including low efficiency of raw material conversion and unintended release of genetically modified microorganisms into the environment, have limited the use of bioprocesses that rely on recombinant microorganisms. Cell-free metabolic engineering is emerging as a new approach that overcomes the limitations of existing cell-based systems. Instead of relying on metabolic processes carried out by living cells, cell-free metabolic engineering harnesses the metabolic activities of cell lysates in vitro. Such approaches offer several potential benefits, including operational simplicity, high conversion yield and productivity, and prevention of environmental release of microorganisms. In this article, we review the recent progress in this field and discuss the prospects of this technique as a next-generation bioconversion platform for the chemical industry.