The biotechnological production of lacewing silk: From gene to protein‐based material

Abstract

Structural proteins are in the spotlight of research and industry due to their versatile properties and the respective potential applications. Besides in-depth studied structural proteins such as spider silk proteins, the proteins within the egg stalk of green lacewings represent another interesting approach for material development. In order to convert such materials into products, biotechnological processes are required to generate a sufficient supply of raw materials. This work describes an innovative and efficient way to recombinantly produce and purify the genetically modified lacewing silk protein N[AS] 8 C (53 kDa) as well its exemplary conversion into silk films. By means of high cell density fermentations applying Escherichia coli (E coli) BL21(DE3) or E coli HMS174(DE3), the successful biosynthesis of the recombinant lacewing silk protein N[AS] 8 C was demonstrated. Interestingly, the formation of an intracellular, highly insoluble silk protein fraction was observed. A tailored purification strategy was developed, allowing the isolation and purification of the insoluble intracellular silk aggregates. Furthermore, the processing of the purified lacewing silk proteins into transparent films was also documented. Based on structural studies (ATR-FTIR), a dominant antiparallel -sheet-orientation was observed in purified silk protein powder as well as in the processed silk materials, which can be attributed to the cross--structure characteristic to lacewing egg stalk silk proteins. K E Y W O R D Sbiomaterial, fermentation, lacewing silk, purification, silk 1 This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.