ENGINEERING SUCCESS · 02
Our first major engineering decision was deciding what should happen to DEHP after our bacteria encountered it.
At first, degradation seemed like the obvious solution. If DEHP could be broken down, the original contaminant would disappear. But engineering a degradation pathway meant we also had to understand everything that pathway produced.
TWO POSSIBILITIES
Use enzymes to transform DEHP into smaller chemical compounds.
Bind DEHP to the bacterial surface and remove the bacteria-containing material from the environment.
DEGRADATION CANDIDATES
We investigated EstS1 and MphG1 as possible enzymes for breaking down DEHP. This gave us a way to explore whether degradation could provide a better endpoint than simply capturing the molecule.
A candidate esterase investigated as part of our degradation strategy.
Another candidate explored for its potential role in transforming phthalate compounds.
THE PROBLEM
One of the biggest problems with the degradation approach was the formation of MEHP.
Instead of simply making the original problem disappear, degradation could transform DEHP into another compound that we would then need to consider.
Are we actually solving the problem if we create another compound that still needs to be addressed?
A BIGGER PROBLEM
Rather than creating a new chain of compounds that we would have to track and evaluate, we began looking more seriously at whether capture and removal could give us a cleaner endpoint.
```A DIFFERENT APPROACH
Instead of introducing another degradation pathway, we investigated the natural ability of our bacterial chassis, LGG, to interact with hydrophobic compounds.
This shifted our thinking. We did not necessarily need to engineer a complicated pathway if the bacterium could already provide a useful starting point for DEHP sequestration.
DEHP becomes associated with the bacterial surface
ENGINEERING DECISION
We chose to move forward with sequestration rather than degradation. By capturing DEHP instead of transforming it, we could focus our engineering efforts on binding the contaminant and physically removing it from the system.
But one question remained: what should do the capturing?
NEXT · GATE 2
We next explored whether we should engineer a protein specifically for DEHP binding—or let the bacterium itself do the work.
Enter Gate 2 → ```