Team:Stony Brook/Description

iGEM SBU 2021

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Project Description

The Problem


Toxins from cyanobacterial harmful algal blooms (cHABs) contaminate lakes and cause severe illness or even death in humans and animals who consume contaminated water. Microcystin-LR (MC-LR) is one such toxin that is ubiquitous in lakes with cHABs. MC-LR is a potent hepatotoxin and carcinogen, damaging the liver by binding to protein phosphatases and inhibiting key biochemical pathways (Woolbright et al., 2017). This not only creates a significant threat to human and animal health, but also leads to a biodiversity crisis (Magrann et al., 2012). The severe overgrowths of aerobic algae that occur during cHABs also consume excessive amounts of oxygen, decreasing the oxygen saturation of the body of water. Oftentimes, the resultant oxygen saturation level is so low that it is prohibitive to the survival of other aerobic species of algae, zooplankton, plants, and animals in the aquatic biome. In recent years, algal blooms have become an increasingly concerning public health, environmental, and biodiversity crisis.

Figure 1. Algal Blooms in Roth Bond at Stony Brook (Gobler Lab Joins the Battle Against Algal Blooms | SBU News, 2021).

Current industrial Methods

  1. Ozonation
  2. Chlorination
  3. Activated Charcoal Absorption


Global warming and climate change have exacerbated the issue. In recent decades, there has been a dramatic increase in the incidence of cHABs worldwide, attributable not only to a greater frequency of preexisting blooms but also to the spread of toxic species to previously unaffected areas (Anderson et al., 2021). Ocean warming, fertilizer runoff, and aquaculture expansion are all factors that exacerbate the issue. Among the hundreds of different cHAB toxins, MC-LR levels specifically have been found to positively correlate with water temperatures (Lürling et al., 2017). With no end in sight for these exacerbating factors, cHABs will only continue to become an increasingly severe concern; the development of an affordable and effective method of MC-LR degradation is crucial.

The Solution: Introducing Pac-Coli

Our project aims to develop a novel microcystin degradation solution by utilizing recombinant E. coli that heterologously over-express MlrA, or microcystinase, an enzyme known to degrade MC-LR in the native Sphingomonas sp. Two approaches have been developed to address this issue. One strain will express MlrA anchored to the outer membrane via a fusion protein with poly-γ-glutamic (PgsA), and the other will freely secrete MlrA into the periplasm via a modified twin arginine translocase (Tat) secretion system. This project also proposes a microcystin detection method using a two-hybrid bacterial assay, which generates a fluorescence signal based on protein-protein interactions through the use of the messenger molecule cAMP.


Anderson, D. M., Fensin, E., Gobler, C. J., Hoeglund, A. E., Hubbard, K. A., Kulis, D. M., Landsberg, J. H., Lefebvre, K. A., Provoost, P., Richlen, M. L., Smith, J. L., Solow, A. R., & Trainer, V. L. (2021). Marine harmful algal blooms (HABs) in the United States: History, current status and future trends. Harmful Algae, 102, 101975.

Gobler Lab Joins the Battle Against Algal Blooms | | SBU News. (2021, April 26). SBU News.

Lürling, M., van Oosterhout, F., & Faassen, E. (2017). Eutrophication and Warming Boost Cyanobacterial Biomass and Microcystins. Toxins, 9(2), 64.

Magrann, T., Dunbar, S. G., Boskovic, D. S., & Hayes, W. K. (2012). Impacts of Microcystis on algal biodiversity and use of new technology to remove Microcystis and dissolved nutrients. Lakes & Reservoirs: Research & Management, 17(3), 231–239.

Woolbright, B. L., Williams, C. D., Ni, H., Kumer, S. C., Schmitt, T., Kane, B., & Jaeschke, H. (2017). Microcystin-LR induced liver injury in mice and in primary human hepatocytes is caused by oncotic necrosis. Toxicon, 125, 99–109.