Week 1 HW: Biomanufacturing with Halophiles
Week 1 Homework – Biomanufacturing Idea
1. What I want to biomanufacture and why
I want to produce polyhydroxyalkanoates (PHA), a type of biodegradable bioplastic, using halophilic bacteria.
PHA can be used as a more sustainable alternative to regular plastic for packaging, disposable items, or even some medical materials. What interests me is that certain bacteria can make this plastic inside their cells when grown under stress conditions. Using extremophiles (especially salt-loving ones) could make the whole process cheaper and simpler because they can grow in open, non-sterile conditions with seawater or high-salt media. This connects well with sustainability and next-generation industrial biotechnology.
2. What living system would I use?
I would use a halophilic bacterium, for example Halomonas bluephagenesis or a similar engineered Halomonas strain.
These bacteria naturally accumulate PHA as a storage material when carbon is available but other nutrients are limited. Because they grow well in high-salt conditions, contamination by normal bacteria is reduced, which allows open or continuous fermentation without strict sterilization.
Inputs would be a carbon source (sugar, waste glycerol, or other cheap substrates), salt, and basic nutrients. The cells produce PHA granules inside them, which can later be extracted.
3. How would I use automation?
For the laboratory and optimization stage I would use a liquid-handling robot such as an Opentrons OT-2.
I would automate media preparation, setting up many parallel small cultures, sampling, and basic measurements (growth and PHA content). This would help test different conditions and engineered strains faster. At larger scale, automation would focus on process control, feeding, and monitoring in continuous or semi-continuous bioreactors. The high-salt environment of halophiles already reduces the need for complex sterile handling, which makes automation simpler.
4. How much would I need to make, and how long would it take?
(a) How much?
A meaningful pilot scale could be enough PHA to produce packaging material for a small product line, for example the equivalent of 10,000 medium-sized plastic bags or containers.
Assuming each item uses roughly 10–15 grams of PHA, the total amount needed would be around 100–150 kg of purified PHA.
(b) How long?
Engineered Halomonas strains can reach high cell densities and accumulate a large percentage of their dry weight as PHA. Published systems have shown good productivity in continuous open fermentation.
With a few hundred liters of working volume running continuously or in repeated batches, producing 100–150 kg could realistically take 1–3 months, depending on the exact yield, recovery efficiency, and how many reactors are used. Early optimization with small-scale automation would take additional weeks.
5. What I still don’t know
The main things I still need to figure out are:
- Real yields and productivity under the specific cheap carbon sources I would like to use.
- How efficient and cost-effective the extraction and purification of PHA is at larger scale.
- Long-term stability of the engineered strains during continuous open fermentation.
- The final material properties of the PHA (strength, flexibility, degradation rate) for real packaging applications.
- Overall production cost compared with petroleum-based plastics and other bioplastics.
These questions would need small pilot experiments and some basic techno-economic calculations. At this stage the goal is to connect the main ideas rather than present a fully optimized process.
AI note
I used grok AI to help research halophiles and PHA production and to organize the structure. The final idea and writing are my own.