Part:BBa_K4719008
RBS4
Introduction
Vilnius-Lithuania iGEM 2023 team's goal was to create synthetic biology tools for in vivo alterations of Komagataeibacter xylinus bacterial cellulose polymer composition. Firstly, we chose to produce a cellulose-chitin copolymer that would later be deacetylated, creating bacterial cellulose-chitosan. This polymer is an easily modifiable platform when compared to bacterial cellulose. The enhanced chemical reactivity of the bacterial cellulose-chitosan polymer allows for specific functionalizations in the biomedicine field, such as scaffold design. As a second approach, we designed indigo-dyed cellulose that could be used as a green chemistry way to apply cellulose in the textile industry. Lastly, we have achieved a of bacterial cellulose and polyhydroxybutyrate (PHB) composite, which is synthesized by K. xylinus.
Bacterial cellulose-chitin polymer was achieved by increasing the production of UDP-N-acetylglucosamine, which can be recognized as a viable substrate for cellulose synthase and incorporated in the bacterial cellulose polymer. We employed two strategies to produce this material. The first approach was to add N-acetylglucosamine into the growth medium BBa_K4719013, and the second one was the production of N-acetylglucosamine by K. xylinus from simple sugars such as glucose, fructose, and saccharose in the growth medium BBa_K4719014.
Colorful cellulose was made by introducing flavin-dependent monooxygenase pKARA_RT3 BBa_K4719018 to K. xylinus. This enzyme can metabolize indigo and its other derivatives into indigo dyes. Bacteria produce cellulose alongside pigments, since they are not water soluble, the final product retains the color.
We produced bacterial cellulose - PHB composite by introducing PHB synthesis operon into K. xylinus BBa_K4719017. The bacteria simultaneously produce both polymers, which are combined into the same material during the purification process.
Usage and Biology
RBS2 is a strong ribosome binding site that was characterized by M. H. Tan (2019) for Acetobacteraceae. This part is a 4-5 fold stronger ribose binding site than the part BBa_B0034 they used as a reference (1). We used this part in our composites to promote protein expression and facilitate cloning by Gibson assembly.
References
1. Teh, M.Y. et al. (2019) ‘An expanded synthetic biology toolkit for gene expression control in acetobacteraceae’, ACS Synthetic Biology, 8(4), pp. 708–723. doi:10.1021/acssynbio.8b00168.
Sequence and Features
- 10COMPATIBLE WITH RFC[10]
- 12COMPATIBLE WITH RFC[12]
- 21COMPATIBLE WITH RFC[21]
- 23COMPATIBLE WITH RFC[23]
- 25COMPATIBLE WITH RFC[25]
- 1000COMPATIBLE WITH RFC[1000]
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