Origin & Molecular
Origin
I’ve been thinking about using engineered algae in wastewater treatment to pull CO2 and produce biofuel—maybe we could model the carbon flux in a spreadsheet and then actually test it in a pilot. How would you set up the protocol?
Molecular
**Protocol Outline**
1. **Define Objectives & KPIs**
- CO₂ removal rate (kg CO₂/m³‑d)
- Biofuel yield (L biofuel/kg biomass)
- Biomass productivity (g DW/m²‑d)
2. **Create Spreadsheet Model**
- Columns: Day, Influent COD, Influent BOD, Algae Biomass (g DW/m²), CO₂ uptake (kg CO₂/m³), Biofuel (L), Residuals.
- Use formulas for mass balance:
CO₂₍out₎ = CO₂₍in₎ − CO₂₍uptake₎
Biomass₍new₎ = Biomass₍old₎ + Growth − Harvest.
- Sensitivity analysis: vary light intensity, temperature, N:P ratio.
- Insert control group data (no algae) for baseline.
3. **Lab‑Scale Setup (pilot)**
- Reactor: 50 L photobioreactor, flat‑panel, transparent.
- Inoculum: 10 g DW/L engineered strain.
- Feed: Synthetic wastewater matching model’s COD/BOD.
- Lighting: LED, 200 µmol m⁻² s⁻¹, 16 h photoperiod.
- Aeration: 1 vvm, sparge to keep CO₂ dissolved.
- Temperature: 25 °C, monitor with sensor.
4. **Sampling & Data Logging**
- Daily: measure CO₂ partial pressure, pH, dissolved oxygen, biomass optical density (OD₇₅₀).
- Weekly: dry weight, lipid extraction for biofuel potential.
- Input data into spreadsheet real‑time (Google Sheets API or Excel macros).
5. **Harvest & Biofuel Extraction**
- Every 7 days: centrifuge 10 L, dry, extract lipids with hexane.
- Convert lipids to biodiesel via transesterification (methanol + NaOH).
- Quantify product volume, energy density.
6. **Control Group**
- Run identical reactor without algae, same feed, same aeration.
- Use data for comparison in spreadsheet: CO₂ removal, residual COD/BOD.
7. **Iterate**
- Update model parameters with pilot data.
- Optimize light, CO₂ supply, nutrient mix.
- Document every tweak: variable, value, outcome.
8. **Safety & QC**
- Keep lab notebooks.
- Verify strain identity by PCR after each harvest.
- Dispose of wastewater according to regulations.
Follow the spreadsheet, keep variables tidy, and let the data drive the next tweak.
Origin
That’s a solid plan—nice that you’ve already built the spreadsheet. I’d add a quick sanity check on the light spectrum; algae often respond better to blue‑rich LEDs. Also keep an eye on the pH drift when you’re feeding synthetic wastewater—sometimes the algae can acidify the medium fast. Let me know how the first week goes; we can tweak the N:P ratio if the biomass starts plateauing. Good luck!