Scientists at the University of Turku in Finland have demonstrated that photosynthetic microorganisms can function as stable, long-lived biocatalysts when immobilized in solid nanocellulose films rather than grown in liquid suspension. The approach addresses a persistent limitation of suspension cultures: self-shading, where cells near the light source block illumination from reaching deeper layers, reducing light-use efficiency and complicating scale-up.
The research team, led by Professor Yagut Allahverdiyeva-Rinne, entrapped engineered ethylene-producing cyanobacteria within nanocellulose scaffolds developed at VTT Technical Research Centre of Finland. The matrix maintains cell hydration and fitness while restricting cell division, directing more captured carbon and energy toward the target chemical instead of biomass accumulation.
In a continuous-flow biofilm reactor, the living films remained productive for more than four months, generating up to approximately twice as much ethylene as comparable suspension cultures over the same period. Senior Research Fellow Sergey Kosourov noted that most photosynthetic bioproduction studies focus on peak rates over short intervals, whereas practical applications require sustained operation over weeks or months.
The nanocellulose formulations were also shown to be biodegradable, supporting the potential for recyclable materials in future production systems. The work builds on an earlier study in which the team layered cells with different light-harvesting antenna sizes to distribute light more evenly through the biocatalyst, substantially improving light-to-product conversion efficiency.
Together, the studies indicate that both long-term stability and improved light management can be engineered by controlling the spatial organization of photosynthetic cells within solid-state architectures. The researchers acknowledge the technology remains at the laboratory stage and that further work is needed to increase productivity, improve product recovery, and scale the platform to pilot-scale reactors.
If successful, the biohybrid approach could enable a new generation of low-energy, solar-driven biomanufacturing systems for renewable chemicals and fuels. The findings were published in Trends in Biotechnology.
Photosynthetic microorganisms achieve long-lasting and renewable chemical production
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