Emancipating sense codons toward a minimized genetic code is of significant interest to science and engineering. A key approach toward sense codon emancipation is the targeted in vitro removal of native tRNA. However, challenges remain such as the insufficient depletion of tRNA in lysate-based in vitro systems and the high cost of the purified components system (PURE). Here we used RNase-coated superparamagnetic beads to efficiently degrade E. coli endogenous tRNA. The presented method removes > 99% of tRNA in cell lysates, while partially preserving cell-free protein synthesis activity. The resulting tRNA-depleted lysate is compatible with in vitro-transcribed synthetic tRNA for the production of peptides and proteins. Additionally, we directly measured residual tRNA using quantitative real-time PCR. (C) 2017 American Institute of Chemical Engineers