Week 1 HW: Final Project Ideas

this page includes Class Assigment of week 1 Biomanufacturing Proposal: Photosynthetic Living Building Materials (LBMs)

1. What you would like to biomanufacture and why? Target Product: Photosynthetic Living Building Materials (LBMs). These are eco-friendly structural bricks composed of an inert matrix (neutralized mining tailings or fine quartz sand) and a biodegradable hydrogel (sodium alginate or gelatin), structurally consolidated through cyanobacteria-induced photosynthetic biomineralization of calcium carbonate (CaCO3). Target Audience/beneficiaries Mining communities and cooperatives in remote regions (e.g., the Bolivian Altiplano and Valleys). Isolated locations facing high transport costs for traditional materials and managing tons of physical waste (tailings) ready to be upcycled. Urban green construction industry. Developers seeking low-carbon alternatives to conventional Portland cement to earn sustainability certifications. Motivation Mining operations produce massive amounts of pulverized tailing waste. Instead of purchasing and transporting clean commercial sand, this project utilizes neutralized mining tailings as the primary physical aggregate, trapping fine fugitive dust within a solid biocement matrix and turning an environmental liability into a local raw material (Zhu et al., 2022). In addition, in isolated mining camps and settlements, freight costs for standard cement are disproportionately high. Biomanufacturing allows transporting only the biological inoculum and polymers (less than 5% of total mass), leveraging local tailings waste and abundant solar radiation in situ to produce community infrastructure (retaining walls, shelter structures, and greenhouses) (Heveran et al., 2020).

Traditional cement manufacturing accounts for ~8% of global CO2 emissions. These living blocks capture and sequester atmospheric CO_2 during biomanufacturing, operating as a net carbon-negative process (Qiu et al., 2021). Retaining viable cyanobacteria in a dormant state inside the matrix grants the material self-healing capabilities (biogenic sealing of microcracks upon rehydration), reducing maintenance costs in extreme climates (Heveran et al., 2020).

2. What living system would you use? Living System Chassis: A microbial biomanufacturing platform based on the fast-growing, extremophilic cyanobacteria Synechococcus sp. PCC 7002

Inputs to the System: -> Physical Substrate: Neutralized mining tailings / fine quartz sand + sodium alginate or gelatin hydrogel. -> Chemical Inputs/Nutrients: Calcium chloride(CaCl2, as Ca source), sodium bicarbonate (NaHCO3) or gaseous CO2, and synthetic BG-11 growth media. -> Energy: Ligth (PAR: 150 - 200 umol/m2/s). Biological Processes: Photosyntesis & Carbon Fixation: Cyanobacteria consume CO2/HCO3, driving local microenvironmental pH up to alkaline levels (pH>8.8) (Zhu et al., 2022).

Photosynthetically-Induced Carbonate Precipitation (PCP): Microenvironmental alkalinization causes Ca^{2+} ions to react with generated CO_3^{2-}, precipitating calcite crystals (CaCO_3) within the extracellular polymeric substance (EPS) matrix surrounding the tailings/sand grains (Qiu et al., 2021).

Outputs of the System: A rigid, biomineralized structural brick reaching compressive strengths > 3.5 MPa (Heveran et al., 2020). Net capture of CO_2 permanently sequestered within the mineral matrix.

Key Assumptions: Light and liquid nutrients penetrate uniformly through the porous matrix due to the initial optical transparency of the hydrogel binder.The cyanobacterial strain tolerates Ca+2 concentrations up to 50mM without osmotic stress inhibition (Heveran et al., 2020).

3. How would ypu use automation? Automation Technology: A benchtop robotic liquid handler (e.g., Opentrons OT-2) integrated with an automated photobioreactor and an IoT-monitored curing chamber.

Workflow Automated: High-throughput formulation optimization, hydrogel blending, and cell inoculation.

Why Automate this Part? Initial cell density (OD730), biopolymer-to-aggregate ratio, and calcium source concentration are critically interdependent variables. The Opentrons OT-2 automates high-throughput screening in microplates to map CaCO3 precipitation kinetics. By automatically screening dozens of combinations of CaCl2, NaHCO3, and cell densities, the robot rapidly identifies the optimal setting “recipe” prior to scaling up to physical molds (Qiu et al., 2021).

4. How much would you need to make, and how long would it take? a. How Much? Scale Defined: Construction of 1 small ecological module or structure (e.g., a retaining wall for a community greenhouse measuring 3m x 2m).

Dimensions & Volume: Standard living brick dimensions: 20cm x 10cm x 5m = 1,000cm3 = 1 Liter (0.001m^3).A wall measuring 3m (length) x 2m (height) x 0.1m (thickness) has a total volume of 0.6m3. Total Quantity Needed: 0.6 m3/0.001m3 = 600 living bricks.

Mass Estimate: Typical living brick density: ~1.8g/cm3 = 1,800 kg/m3 (Heveran et al., 2020). Mass per brick: 1.8 kg. Total mass required: 600 x 1.8 kg = 1,080kg (~1.08 metric tons of material).

b. How Long? Prototype Scale (Automation stage with Opentrons): Automated high-throughput microplate formulation screening: 1–2 execution days.

Manufacturing at Scale (600 Bricks): Biomass Required: Requires a target inoculum density of OD730~1.5(~0.5 g dry biomass/L). For a total batch mixture of 600 L (assuming 10% volume inoculum = 60 L of dense cyanobacterial culture). Biomass Cultivation Time: In an automated 60 L photobioreactor, reaching target density takes approximately 5 days. Curing/Mineralization Time in Molds: Each brick batch requires 7 days inside the photo-curing chamber (supplied with PAR light, humidity, and CaCl2) to achieve sufficient calcite precipitation (Heveran et al., 2020). Reactor/Mold Capacity: Assuming an automated parallel curing rack holding 100 molds per batch: Required batches: 600/100 = 6 batches. Total Estimated Production Time:Batch 1: 5 days (biomass) + 7 days (curing) = 12 days. Batches 2 to 6 (running in a continuous staggered pipeline): 7 days per additional batch. Total Production Time: ~47 days (~1.5 months to produce the complete wall).

5. What What don’t you know yet? he maximum depth to which light can penetrate the brick once calcite begins precipitating and opacifying the material remains uncertain (Qiu et al., 2021). Will biomineralization be homogeneous at the center of a 10 cm brick, or will it only occur within the outer 1.5 cm shell?

The exact percentage of cyanobacteria surviving in a dormant state after final structural drying, as well as how many months or years they retain self-healing functional activity upon rehydration, requires experimental verification (Heveran et al., 2020).

Quantifying the maximum compressive strength (MPa) achievable without over-compacting the material—which would destroy the pore network required for gas exchange and light transmission—remains an open question (Zhu et al., 2022).

References Heveran, C. M., Williams, S. L., Qiu, J., Artier, J., Hubler, M. H., Cook, S. M., & Srubar, W. V. (2020). “Biomineralized materials as living building materials with load-bearing and regenerative capabilities.” Matter, 2(2), 481-494.

Heveran, C. M., Williams, S. L., Qiu, J., Artier, J., Hubler, M. H., Cook, S. M., & Srubar, W. V. (2020). “Biomineralized materials as living building materials with load-bearing and regenerative capabilities.” Matter, 2(2), 481-494.

Zhu, T., Dittrich, M., & Liu, X. (2022). “Microbially induced carbonate precipitation (MICP) via cyanobacteria for soil stabilization and eco-friendly construction materials.” Construction and Building Materials, 320, 126233.

Final Project