Microbial Photosynthetic System Shows Promise for Efficient Chemical Production

Finnish researchers have developed a novel microbial photosynthetic system that entraps engineered cyanobacteria in thin nanocellulose films, enabling sustained ethylene production for more than four months while generating approximately twice as much ethylene as comparable suspension cultures. The breakthrough, announced by the University of Turku, could pave the way for more sustainable and environmentally friendly methods of chemical manufacturing.

The research, published in the journal Trends in Biotechnology on 2 July 2026, represents a significant advance in the field of photosynthetic biomanufacturing. By addressing key limitations of traditional suspension culture systems, the new approach offers a potential path toward renewable chemical production using sunlight and atmospheric carbon dioxide.

The Challenge of Photosynthetic Chemical Production

Photosynthetic microorganisms, such as cyanobacteria and algae, can use light energy to convert carbon dioxide into useful compounds under mild, environmentally compatible conditions. However, most current photosynthetic production systems rely on cells growing freely in large volumes of liquid, which creates several significant challenges.

“For practical chemical production, photosynthetic microorganisms need to function not only as growing cultures, but as stable and long-lived biocatalysts,” said Sergey Kosourov, Senior Research Fellow at the University of Turku. “One major limitation of suspension cultures is self-shading: cells near the light source block light from reaching cells deeper in the culture. This reduces the efficiency of light use and creates challenges when scaling the technology toward industrial applications.”

These suspension systems also require substantial quantities of water and energy-intensive mixing to keep cells evenly distributed and exposed to light. Additionally, cells typically remain productive for only a few days before declining.

A Biohybrid Approach

To overcome these limitations, the researchers entrapped engineered cyanobacteria (Synechocystis sp. PCC 6803) within specifically designed nanocellulose films. These cyanobacteria were genetically modified to express the ethylene-forming enzyme from Pseudomonas syringae, enabling them to produce ethylene from atmospheric CO2 through photosynthesis.

The nanocellulose scaffold, developed by researchers at VTT Technical Research Centre of Finland, provides a supportive environment for the living cells. These films act as living biohybrid catalysts in which the cells perform photosynthesis and produce the target chemical while the surrounding material maintains hydration, supports cell fitness, and facilitates light penetration.

“The important advance is that we are combining engineered photosynthetic cells with supporting materials to create functional living systems for chemical production,” said Professor Yagut Allahverdiyeva-Rinne, leader of the Photosynthetic Microbes research group at the University of Turku. “Entrapping the cells within the matrix restricts cell division and excessive biomass accumulation, allowing more of the captured carbon and energy to be directed toward the desired product.”

Sustained Production for Over Four Months

The nanocellulose films containing ethylene-producing cyanobacteria were tested in a continuous-flow biofilm reactor, where they remained moist while exposed to the reactor headspace. Under these conditions, the cyanobacterial films remained productive for more than four months and generated up to approximately twice as much ethylene as comparable suspension cultures.

“Most studies of photosynthetic bioproduction focus on the highest production rate achieved over a relatively short period,” said Kosourov. “For practical applications, however, it is equally important to know whether the cells can remain productive for weeks or months and function as long-lived biocatalysts.”

The researchers also evaluated the biodegradability of the nanocellulose formulations and confirmed that the matrices could be broken down after the production phase, supporting the development of biodegradable and potentially recyclable materials.

Broader Research Program

The ethylene study forms part of a broader research program at the University of Turku to develop effective living photosynthetic catalysts. In an earlier study, the team demonstrated that engineered living materials can be organized in innovative ways to improve light utilization by layering cells with different light-harvesting properties.

“Together, these studies show that the biocatalysts can be designed for both long-term operation and more efficient light use,” Kosourov explained. “By engineering the photosynthetic cells and controlling their spatial organization within the biocatalytic architecture, we can improve light management and address limitations that are difficult to overcome in suspension cultures.”

Implications for Sustainable Manufacturing

Ethylene is one of the most important organic commodity chemicals, with an annual global demand of more than 150 million tons. It is the main building block in the production of plastics, fibers, and other organic materials. Currently, ethylene is produced via steam cracking of fossil hydrocarbon feedstocks, leading to significant CO2 emissions.

If successfully scaled, this technology could provide a more sustainable route to ethylene production, reducing dependence on fossil-based petrochemical processes. The approach could potentially be extended to produce other chemicals beyond ethylene, as the platform concept is adaptable.

Challenges Ahead

The technology remains at the laboratory stage, and further work is needed to increase productivity, improve product recovery, and scale the platform to larger reactors suitable for pilot-scale operation.

“Our next challenge is to translate the performance of small laboratory films into larger, reliable production systems,” said Professor Allahverdiyeva-Rinne. “If successful, this platform could support a new generation of low energy biohybrid technologies for the production of renewable chemicals and fuels.”

The research was reported by Xinhua News Agency from Helsinki and has drawn significant interest across Chinese media platforms, reflecting growing global attention to sustainable chemical production technologies. Additional coverage from Bioengineer.org and AZoLifeSciences highlights the international significance of this research advance.

As the world seeks to transition from fossil-based manufacturing to renewable alternatives, this biohybrid approach represents a meaningful step toward practical solar-driven biomanufacturing.