Team:Hong Kong JSS/Contribution

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Team:Hong Kong JSS/Contribution


In previous iGEM competitions, teams such as 2012 Team UCL London, 2012 Team Bielefeld-Germany, and 2018 Team HKUST have demonstrated the effectiveness of heterogeneously expressed laccase in degrading polyvinyl chloride (PVC) plastics (BBa_K729002) and enzymatic activity in catalyzing ABTS (BBa_K863005). These projects have shown that by expressing and secreting laccase in E. coli is able to utilize the enzymes’ function in real-life applications.

From our knowledge, there is no previous iGEM project addressing the Aflatoxin B1 (AFB1) degrading properties of laccase. Thus, our project is the first one that has done a comprehensive review and preliminary demonstration of the capability of using synthetic laccase as a solution to tackle the aflatoxin contamination problem in iGEM history. Meanwhile, by our literature review, we have also identified a specific laccase (tvLac) that has been reported to have a relatively high and specific activity to degrade AFB1 [1]. (Our part for tvLac:

Meanwhile, F420H2-dependent reductase A (FDR-A) has been studied by iGEM 2017 Team CSMU_NCHU_Taiwan to show that it can be heterogeneously expressed by yeast and maintain the AFB1 catalytic activity (BBa_K2382001). Based on their findings, we further propose to express the FDR-A in a more common and easy to manipulate organism - E .coli. Furthermore, the Nissle 1917 strain E. coli has the probiotic property which makes it more suitable for use in daily applications and in food additives. We have also added the review data that the locus MSMEG_5998 of Mycobacterium smegmatis has the highest activity in AFB1 catalytic activity [2,3] when compared to other loci and other species. (Our part for FDR-A:

From our literature review, we also found an interesting report that showed that bacteria species, such as Bacillus sp., Enterobacter sp., Escherichia sp., etc. have the intrinsic ability to inhibit the growth and AFB1 production in Aspergillus sp.. [4] This further supports our proposed application that is by using the E. coli to preserve the food that is at risk of AFB1 and Aspergillus sp. contamination.

The detailed information that we reviewed please refer to BBa_K729002 and BBa_K2382001 contribution sections.

[1] Okwara, P. C., Afolabi, I. S., & Ahuekwe, E. F. (2021). Application of laccase in aflatoxin B1 degradation: A Review. IOP Conference Series: Materials Science and Engineering, 1107(1), 012178.

[2] Verheecke, C., Liboz, T., & Mathieu, F. (2016). Microbial degradation of aflatoxin B1: Current status and future advances. International Journal of Food Microbiology, 237, 1–9.

[3] Taylor, M. C., Jackson, C. J., Tattersall, D. B., French, N., Peat, T. S., Newman, J., Briggs, L. J., Lapalikar, G. V., Campbell, P. M., Scott, C., Russell, R. J., & Oakeshott, J. G. (2010). Identification and characterization of two families of F420H2-dependent reductases from mycobacteria that catalyse aflatoxin degradation. Molecular Microbiology, 78(3), 561–575.

[4] Peles, F., Sipos, P., Kovács, S., Győri, Z., Pócsi, I., & Pusztahelyi, T. (2021). Biological Control and mitigation of aflatoxin contamination in commodities. Toxins, 13(2), 104.