Could i run ePACE system on eVOLVER?

Hi, I am now planning a ePACE system setup using eVOLVER.

However, there is one question in this regard.

The PACE system requires two major types of bio-reactors.

The first is a ‘MAIN reactor’ that causes infection and reproduction by phage, which corresponds to eVOLVER’s ‘smart sleeve unit’.

But the other important thing is the ‘host cell reactor’, where phages do not exist and only e.coli is cultured.

In the MAIN reactor, e.coli is infected and died, and phage is reproduced. Because this cycle is very short, about 10 minutes, e.coli cannot survive.

Therefore, fresh e.coli hosts must be continuously supplied from the ‘host cell reactor’ to ‘MAIN reactor’.

However, only 16 MAIN reactors exist in eVOLVER which means ‘smart sleeve unit’, but the host cell reactor does not seem to exist.

Of course, there may be a way to use one or two smart sleeve unit as a host cell reactor.

However, since phage’s infection cycle is faster than e.coli’s division rate, the capacity of the host cell reactor should be greater than that of the MAIN reactor

However, all smart sleep units of eVOLVER are designed with the same capacity.

How can I solve this problem?

Could i run PACE system on eVOLVER?

I think I should make a additional host cell reactor. But what worries me is that I don’t know much about mechanical engineering and programming.

Therefore, is it possible to make a host cell bioreactor of about 100ml using sensors and pumps that exist in eVOLVER? (At the expense of one of the 16 smart sleeve units)

I would appreciate it if you could give me your opinion on this.



David Liu make one of sleeve to host cell reactor. three fold-of volume of MAIN reactor

Hey Baelab, yes ePACE on the eVOLVER was described in this paper.

Currently it will be a bit challenging to set up ePACE, as it is an eVOLVER extension and requires some troubleshooting.

Unfortunately, the current ratio is 1 chemostat : 1 lagoon, so each eVOLVER base has 8 of each. @bgwong has gotten a larger chemostat up and running, but it takes up the space of 4 vials.

The problem of assign sleeve to chemostat in a 1:1 ratio will probably be solved by making a separate chemostat.

When @bgwong makes a lager chemostat, isn’t it necessary to make it on the Vial Platform?

If a lager chemostat is built outside of the Vial Platform, all 15 modules will be available.

Only one module will be needed to connect to chemostat by extension cable.

Of course, we will need a larger heater and magnetic motor, but can’t this part be solved with DIY?

You’re absolutely right and it would be amazing if you were able to figure it out! Should be possible by adapting what Brandon has made.

I’ll add here that if you just want to run a few vials you do not need the millifluidics system described in the ePACE paper - you can use slow flow rate pumps available from Fynch for the chemical inducers. There is active development of a smaller eVOLVER system that takes this approach. The millifluidics really only become necessary once you need to control 2+ slow flow rate chemical inducers on the full eVOLVER.

Thank you for your kind reply. @heinsz

Does the slow flow rate pump you mean peristaltic pump?

The Fynchbio only sells a single type of peristaltic pump.

Chemical inducers require a very small volume, and therefore, it seems impossible to control with a peristaltic pump with high a minimum flow.

Of course, it will be solved by diluting the inducers and lowering the concentration, but this may interfere with the media concentration (LB media for e.coli) of main lagoon.

Is there anything I’m mistaken about this?

Fynch sells two kinds of peristaltic pumps. The part numbers are listed in the ePACE NBT paper in the methods section. You can get pumps that have flow rates of ~1 ml/min.

Oh my…

Until now, I knew that only full-kit store page and modules store page exist.

Thanks to you, I just discovered that there is a store page for accessories.

So now, as you said, I think there is a additional option to try to use low flow rate pump.

However, it is still questionable whether the inductor can be controlled with that pump.

According to the ePACE paper, the inducer is controlled by 0.6ul/min.

Can a low flow rate pump do this?

I’d like to ask your opinion on this.

Yup it works fine. You can lower the bolus from 500 ul (which is the minimum amount the fast rate pumps can do) to 50-100 ul (possibly lower - I haven’t thoroughly tested this yet). Then run the pumps as chemostats with that smaller bolus. We have code that will calculate how often to run the pumps given that bolus evenly over an hour to hit desired flow rates.

I have successfully used these pumps for arabinose induction of MP6 in an ePACE experiment.