Related Experiment Video
Updated: Aug 21, 2026

Large-scale Production of Recombinant RNAs on a Circular Scaffold Using a Viroid-derived System in Escherichia coli
Published on: November 30, 2018
Construction of Lactococcus lactis Expression System via Chromosomal Integration of T7 RNA Polymerase for Levan
Kaige Peng1, Fangkun Zhao1, Xuejiao Zhang1
1College of Food Science and Technology, Hebei Agricultural University, 289 Lingyusi Road, Baoding, Hebei071000, China.
Abstract:
Fruit pomace recycling is critical for green biomanufacturing. Lactococcus lactis, a common host for waste valorization, shows poor protein expression in conventional systems. We constructed T7RNAP-driven inducible and constitutive expression systems in L. lactis NZ9000. The two systems increased target gene transcription by 103-fold and 207-fold, and enzyme activity by 5.24-fold and 10.36-fold, respectively. A signal peptide enabled efficient extracellular secretion of recombinant proteins. The engineered strains synthesized levansucrase and levan, achieving yields of 36.27 g/L and 27.53 g/L in sucrose medium. When using food waste substrates, the levan titer reached 8.84 g/L with molasses, and 3.2, 1.4, 0.5, 0.7, 0.5 g/L with sugar cane bagasse and various fruit peels. This work provides a reliable strategy for strain engineering, pomace reuse and low-cost large-scale levan production.
More Related Videos
Related Concept Videos
Operons
Production of Pharmaceuticals
Bacterial Transformation
Bacterial Transformation

