Microalgae-derived PHA / PLA
Biodegradable plastics from alginate and polysaccharides. Applied to food/cosmetics packaging, agricultural mulch, and marine-degradable fishing gear (Costa 2019; Beckstrom 2020).
- LCA
- −2.1 kg-CO₂/kg
- PERMANENCE
- 5–20 yr
Axis 02 · Water & Circular
Axis 02:
Water & Resource Circulation
Axis 02:
Water & Resource Circulation
High-efficiency N / P removal with 40–60% OPEX cut
Microalgae absorb nitrogen and phosphorus from enclosed bays, municipal effluent, and aquaculture discharge directly into harvestable biomass. The pathway substitutes or augments tertiary treatment and plugs into municipal budget lines under Japan's nutrient total-load regulation framework.
N Uptake (HRAP) 3,600–6,200kg/ha·yr Craggs 2012 / García 2006
P Uptake (HRAP) 360–700kg/ha·yr Park & Craggs 2011
OPEX reduction 40–60% vs. tertiary · Falk 2011
Co-product value $500–3,000/t Feed/fertilizer commodity · Chia 2018
Four components of Water · Resource Circulation
TARGET STREAMS
Enclosed bays · sewage · aquaculture effluent
Ariake, Seto Inland Sea, Osaka Bay, Tokyo Bay, Ise Bay. Combined coastal N load ~200,000 t-N/yr under Japan's enclosed-sea total-load regulation (Ministry of the Environment, 2024). All discharge points fall under N/P caps.
01 / 04 STRAIN ENGINEERING
Maximizing growth and uptake
Nannochloropsis · Chlorella · Arthrospira lineages reinforced by adaptive evolution. Salinity and temperature tolerance is co-optimized with nutrient uptake kinetics.
02 / 04 RESOURCE CONVERSION
Liability → feedstock
Absorbed N and P are concentrated inside the biomass as protein, amino acids, and phosphates. A paradigm shift from waste disposal to raw-material production.
03 / 04 ENERGY RECOVERY
Net energy-positive operation
Anaerobic digestion yields +1.2–1.8 kWh/kg (Sialve 2009); pyrolysis adds biochar + heat at +0.6–1.0 kWh/kg (Grierson 2009). Net balance +1.0–2.0 kWh/kg dry biomass supports self-consumption plus grid sale.
04 / 04 Key Metric
−$22 /kg-N
Net OPEX Delta · vs. tertiary · −60% · 150 JPY/USD (OECD 2024)
International Standards
- London Protocol · Annex — compliant with the "bona fide scientific research" provision
- Voluntary credit certifications — Puro.earth / Verra and additional registries
- Puro.earth · Verra · ICVCM — Core Carbon Principles (CCP) aligned
- Verra SD VISta · TNFD — biodiversity and nature-related disclosure
Nitrogen removal cost: legacy vs. Blue Hole
Activated-sludge $17/kg-N and tertiary $37/kg-N versus Blue Hole $15/kg-N (net of co-product credits) — net −$22/kg-N, 60% lower than tertiary (Falk 2011 / Acién 2012).
NET OPEX DELTA
− $22 /kg-N −60% vs. tertiary
Effective cost net of CDR credit and co-product revenue. FX: 150 JPY/USD (OECD 2024).
Axis 02-B: use every biomass fraction
Recovered microalgae biomass is fractionated into lipid, protein, carbohydrate, residue, and shell-CaCO₃ streams. Valorizing every fraction can compress CDR cost by 40–60%.
STEP 01 · COLLECTION
Collection vessels & harvest rafts
Retrofitted fishing boats with mechanical harvesters, paired with autonomous buoy nets. Biomass is landed while wet to avoid pre-dewatering energy losses.
STEP 02 · FRACTIONATION
Fractionation plant
Mechanical disruption + enzymatic separation + membrane filtration separate lipids, proteins, carbohydrates, and ash fractions for sequential downstream routing.
PARALLEL · CALCIFIERS
Calcifiers (oyster & clam shells)
Shells collected in parallel are calcined into CaO / CaCO₃ feedstock for soil amendment, construction additives, and Ocean Alkalinity Enhancement (OAE) alkali supply.
LIPIDS Lipid fraction
Functional food, cosmetics, pharma feedstock (DHA · EPA · squalene). Bulk → premium transition.
PROTEINS Protein fraction
Aquaculture & livestock feed, alternative protein, pet food. FAO-aligned feed grade at $800–1,800/t.
CARBOHYDRATES Carbohydrate fraction
Alginate · carrageenan · bioplastic precursor (PHA/PLA) feedstock (Costa et al. 2019).
RESIDUE Residue
Organic fertilizer · biochar · BECCS feedstock. Recovered C is not double-counted against CDR credits.
CALCIUM CARBONATE Shell CaCO₃
Construction, OAE alkali supply, agricultural lime. SCM replacing 15–25% clinker (Scrivener 2018).
LCA-verifiable carbon-negative products
From recovered biomass to LCA-verifiable circular materials
Downstream products lock carbon for decades to a century. ISO 14040/14044-compliant LCA ensures net-negative performance over the full life cycle (cultivation → end-of-life).
Microalgae & shell cement blend
Biochar and shell CaCO₃ act as supplementary cementitious materials (SCMs). 15–25% cement replacement cuts manufacturing CO₂ and locks carbon into long-lived structures (Scrivener 2018).
- LCA
- −180 kg-CO₂/m³
- PERMANENCE
- 50–100 yr
Microalgae fiber panels
Protein- and cellulose-based fibers molded with natural binders. Used in building interiors, furniture, and insulation to stock carbon inside buildings.
- LCA
- −1.4 kg-CO₂/kg
- PERMANENCE
- 30–60 yr
LCA-Verifiable Carbon Negative: ISO 14040 / 14044 compliant life-cycle assessment demonstrates net-negative GHG across the full value chain. CDR credits and product-LCA are kept distinct from Puro.earth / Verra product-fixation credit pathways to avoid double counting.
Primary sources for all numerical, methodological, and regulatory claims. Forward-looking estimates are explicitly marked as 'target'. Currency conversion uses OECD 2024 annual average ≈ 150 JPY/USD.
- [01] · 2012 — Wastewater treatment and algal biofuel production in high-rate algal ponds · Journal of Applied Phycology 24, 329–337 ↗ doi.org/10.1007/s10811-011-9654-7 HRAP N removal 1.4 g-N/m²·day ≈ 5,100 kg-N/ha·yr.
- [02] · 2006 — High-rate algal pond treating urban wastewater · Bioresource Technology 97, 1709–1715 ↗ doi.org/10.1016/j.biortech.2005.07.019 Areal N uptake 1.0–1.7 g-N/m²·day in HRAPs.
- [03] · 2011 — Nutrient removal in wastewater treatment high rate algal ponds with carbon dioxide addition · Water Science and Technology 63, 1758–1764 ↗ doi.org/10.2166/wst.2011.114 Areal P uptake 0.1–0.2 g-P/m²·day ≈ 360–700 kg-P/ha·yr.
- [04] · 2012 — Production cost of a real microalgae production plant and strategies to reduce it · Biotechnology Advances 30, 1344–1353 ↗ doi.org/10.1016/j.biotechadv.2012.02.005 Biomass cost €4–12/kg DW; derived N-removal cost €10–20/kg-N with co-product credit.
- [05] · 2009 — Anaerobic digestion of microalgae as a necessary step to make microalgal biodiesel sustainable · Biotechnology Advances 27, 409–416 ↗ doi.org/10.1016/j.biotechadv.2009.03.001 Methane yield 0.15–0.55 m³ CH₄/kg VS ≈ 1.5–5.5 kWh/kg dry algal biomass.
- [06] · 2009 — Thermal characterisation of microalgae under slow pyrolysis conditions · Journal of Analytical & Applied Pyrolysis 85, 118–123 ↗ doi.org/10.1016/j.jaap.2008.10.003 Bio-oil + biochar recovery 0.6–1.0 kWh/kg net after process heat.
- [07] · 2011 — Life-cycle assessment of microalgae culture coupled to biogas production · Bioresource Technology 102, 207–214 ↗ doi.org/10.1016/j.biortech.2010.06.154 HRAP + AD net energy ratio 0.8–1.5; upper bound only under optimized operation.
- [08] · 2016 — Water–Energy Nexus — Excerpt from the World Energy Outlook ↗ www.iea.org/reports/water-energy-nexus Tertiary wastewater treatment energy intensity ≈ 0.5 kWh/m³.
- [09] · 2011 — Incorporating life-cycle assessment into wastewater treatment plant design · Water Environment Research 83, 2203 ↗ doi.org/10.2175/106143011X13075599870946 Tertiary biological nitrogen removal incremental cost $15–50/kg-N.
- [10] · 2024 — 閉鎖性海域の水質汚濁に係る総量削減 — 東京湾・伊勢湾・瀬戸内海・有明海・八代海 ↗ www.env.go.jp/water/heisa/heisa_net/ Sum of enclosed-sea N loads ≈ 200,000 t-N/yr under 総量削減 framework.
- [11] · 2024 — 瀬戸内海環境保全特別措置法 · N/P 総量削減制度 ↗ www.env.go.jp/water/heisa/setouchi.html Statutory framework for coastal N/P total-load regulation since 2001.
- [12] · 2018 — Analysis of economic and environmental aspects of microalgae biorefinery for biofuels production: A review · Biotechnology Journal 13, 1700618 ↗ doi.org/10.1002/biot.201700618 Commodity-grade microalgae biomass $500–3,000/t (feed/fertilizer); high-value food/nutraceutical >$10,000/t.
- [13] · 2016 — Towards industrial products from microalgae · Energy & Environmental Science 9, 3036–3043 ↗ doi.org/10.1039/C6EE01493C Microalgae biorefinery value chains with biomass production cost projections €3–5/kg dry at scale.
- [14] · 2011 — Microalgal production — A close look at the economics · Biotechnology Advances 29, 24–27 ↗ doi.org/10.1016/j.biotechadv.2010.08.005 Photobioreactor €4.95/kg, raceway €4.95–5.91/kg microalgal biomass production cost baseline.
- [15] · 2019 — Microalgae as source of polyhydroxyalkanoates (PHAs) — A review · International Journal of Biological Macromolecules 131, 536–547 ↗ doi.org/10.1016/j.ijbiomac.2019.03.099 Microalgae-derived PHA/PLA as biodegradable plastic feedstock.
- [16] · 2020 — Bioplastic feedstock production from microalgae with fuel co-products: A techno-economic and life-cycle assessment · Algal Research 46, 101769 ↗ doi.org/10.1016/j.algal.2019.101769 LCA of microalgae-derived PHA: GHG balance neutral to net-negative depending on allocation.
- [17] · 2018 — Eco-efficient cements: Potential economically viable solutions for a low-CO₂ cement-based materials industry · Cement and Concrete Research 114, 2–26 ↗ doi.org/10.1016/j.cemconres.2018.03.015 Supplementary cementitious materials (SCMs) can replace 15–30% of clinker with comparable durability.
- [18] · 2006 — ISO 14040:2006 / 14044:2006 — Life Cycle Assessment principles, framework and requirements ↗ www.iso.org/standard/37456.html Governing standard for cradle-to-grave LCA methodology.
- [19] · 2024 — Exchange rates (annual average JPY/USD) ↗ data.oecd.org/conversion/exchange-rates.htm 2024 annual average ≈ 150 JPY/USD used throughout this site for currency conversion.