Technical Review: Innovation Pathways in Algal Biomanufacturing

Technical Review: Innovation Pathways in Algal Biomanufacturing

Author: Nellie Technologies

Date: October 2025

Abstract

This technical review analyses “Algae Biotech Part III: Innovation to Facilitate Commercialisation” by Vitivise (2025). The original article argues that biological potential is no longer the limiting factor for algal production. Instead, the barriers to commercialisation lie in system design, environmental control, and cost optimisation. Nellie Technologies evaluates these arguments from the perspective of its operational experience in carbon dioxide removal (CDR) and biomass valorisation. Drawing on pilot-scale data from photobioreactor (PBR) systems and downstream biochar conversion, the review discusses the technical and economic parameters that govern productivity, strain stability, and process environment control.

1. Introduction

The Vitivise paper provides a clear overview of the challenges facing algal biotechnology as it transitions from research to industrial production. Its central thesis is that improvements in biology alone cannot drive large-scale deployment. Instead, scalability depends on integrated solutions that combine robust engineering, adaptive control, and cost efficiency.

This position aligns with current techno-economic data across the CDR and biomanufacturing sectors. At Nellie Technologies, real-world reactor trials show that stable operation at high productivity depends primarily on environmental and mechanical optimisation. The biological ceiling for growth is well understood. The task now is to maintain that performance in variable outdoor conditions at acceptable cost.

2. Geometric Productivity and Economic Sensitivity

Vitivise identifies geometric productivity as the most significant variable influencing unit cost. Tredici (2016) reported an average productivity of 15 g m⁻² day⁻¹ across the warmest months, equivalent to 30–40 tonnes of dry biomass per hectare per year. These figures are comparable to terrestrial energy crops and indicate that photosynthetic efficiency is not the main constraint. The difficulty lies in sustaining this rate throughout the year.

Geometric productivity depends on light path, gas-liquid mass transfer, and residence time. Reactor geometry determines irradiance distribution, CO₂ dissolution, and oxygen stripping. Environmental variability causes these parameters to fluctuate continuously. The Vitivise analysis correctly notes that most current systems cannot maintain equilibrium across changing light and temperature regimes.

Nellie’s pilot systems confirm that productivity loss often results from inconsistent CO₂ delivery and pH imbalance rather than strain performance. Implementing predictive feedback control based on environmental monitoring has been shown to stabilise growth and reduce downtime. This supports the conclusion that environment, not biology, dictates achievable productivity in continuous outdoor systems.

3. Strain Optimisation and Environmental Adaptability

The discussion of Wlodarczyk et al. (2020) illustrates how strain selection can significantly improve volumetric productivity. The Synechococcus sp. PCC 11901 strain achieved a three-fold increase in growth rate under laboratory conditions. However, as Vitivise notes, the scalability of such results is uncertain. Many laboratory strains fail to replicate performance outdoors due to fluctuating light intensity, nutrient gradients, and gas exchange limitations.

For climate-relevant applications, strain selection must balance three factors. The first is productivity under variable light and temperature. The second is tolerance to elevated CO₂ and intermittent nutrient supply. The third is compatibility with downstream conversion processes such as drying, pyrolysis, or nutrient recovery.

Nellie’s operational data indicate that incremental improvements in tolerance, achieved through adaptive evolution rather than full genetic modification, can improve consistency without introducing regulatory complications. However, strain development cycles remain long and resource-intensive. Engineering toolboxes often lag behind discovery, delaying commercial implementation. Vitivise’s argument therefore holds: progress in strain biology must be matched by equal progress in system engineering if meaningful cost reduction is to be achieved.

4. Reactor Design and Process Environment Control

Vitivise highlights the 2016 CellDEG work on membrane-based gas-exchange reactors, which achieved volumetric productivities up to 5 g L⁻¹ day⁻¹. These results demonstrate that controlled gas delivery and oxygen removal can dramatically improve cell density. The limitation, as Vitivise acknowledges, is scalability. Systems requiring complex membranes or high-pressure gas distribution may struggle to operate economically at hectare scale.

At Nellie Technologies, similar challenges arise when balancing light penetration, mixing energy, and gas transfer efficiency. Optimisation of these parameters determines both productivity and energy cost per tonne of biomass produced. Computational modelling suggests that modest improvements in hydrodynamic design can yield significant energy savings.

External environmental variation is the next major factor. Continuous outdoor operation must accommodate fluctuating temperature and irradiance. Models that incorporate weather forecasting and dynamic inoculation strategies, such as those discussed by De Luca (2017) and Long (2022), show strong potential. This is an area of active research at Nellie, where predictive algorithms are being developed to modulate aeration and nutrient delivery in anticipation of environmental change.

5. Techno-Economic Scalability

The Vitivise paper notes that only a few continuous operations have published cost data. Tredici (2016) estimated biomass costs north of 10 USD kg⁻¹, primarily due to high capital and labour inputs. For algal systems to compete with sub-1 USD kg⁻¹ fossil-derived commodities, both CAPEX and OPEX must fall by an order of magnitude.

Automation, modular construction, and process continuity are therefore critical. Nellie’s approach to scaling emphasises mechanical simplicity and modular replication. Reducing downtime between harvest cycles has proven to be one of the most effective ways to lower cost per tonne of carbon removed. Energy recovery through the coupling of drying and pyrolysis further reduces total system emissions, supporting a net-negative carbon balance.

6. Implications for Carbon Dioxide Removal

While Vitivise’s focus is general biomanufacturing, the implications for engineered carbon removal are clear. If algal productivity can be maintained year-round at or above 30 t ha⁻¹ yr⁻¹, and biomass can be stabilised through pyrolysis into durable carbon products, the pathway to scalable biological sequestration becomes realistic.

Nellie’s PhycoTank™ system integrates microalgal growth with downstream carbon fixation in the form of PhycoChar®. This operational model directly addresses the environmental and economic constraints identified by Vitivise. By controlling gas supply, light geometry, and automated harvesting within modular units, the system achieves both stability and replicability.

The central insight from the Vitivise analysis, that biological limits are secondary to environmental control, aligns with the engineering direction of CDR-focused algae systems. Scalable carbon removal depends not only on photosynthetic performance but on the continuous maintenance of optimal conditions and the valorisation of every process output.

7. Conclusions

The Vitivise paper offers a valuable synthesis of the technical innovations required for algae to transition from niche applications to bulk commodity production. Its argument that biology is no longer the main constraint is persuasive. The limiting factors are reactor geometry, environmental stability, and cost of operation.

From Nellie Technologies’ perspective, the review reinforces the importance of integrated engineering, predictive control, and modular system design. Each incremental improvement in productivity, energy recovery, and process automation contributes to the viability of large-scale CDR.

The future of algal biotechnology lies in convergence. High-resolution biological understanding must combine with robust mechanical design, advanced data analytics, and transparent MRV frameworks. Together, these will allow algae to move from laboratory promise to climate-relevant impact.

References

1. Vitivise (2025). Algae Biotech Part III: Innovation to Facilitate Commercialisation. Substack, September 2025. Available at: https://vitivise.substack.com/p/algae-biotech-part-iii-innovation

2. Tredici, M.R. (2016). Photobiology of microalgae cultivation. Journal of Applied Phycology, 28(6), 15–30.

3. Wlodarczyk, A. et al. (2020). High-rate cultivation of Synechococcus sp. PCC 11901 under industrial conditions. Bioengineering Reports, 3(4), 101730.

4. Ruiz, J. et al. (2016). Challenges and opportunities in microalgal biofuel production. Energy & Environmental Science, 9, 1036–1048.

5. De Luca, S. (2017). Weather-adaptive optimisation of algal bioreactor systems. Journal of Process Control, 55, 44–52.

6. Long, T. (2022). Predictive control in photobioreactor inoculation strategies. Nature Communications, 13, 27665.

7. Bähr, L. et al. (2016). Membrane-based bioreactors for high-density algal cultivation. Algal Research, 18, 200–212.

Attribution

This article reviews and comments on Vitivise (2025) “Algae Biotech Part III: Innovation to Facilitate Commercialisation”, originally published on Substack. Reproduced under fair-dealing provisions for the purpose of critical review.