iTechGuides is reader-supported. When you buy through links on our site, we may earn an affiliate commission. As an Amazon Associate I earn from qualifying purchases. Learn more
Researchers boosted hydrogen-evolution activity in a laboratory assay by changing how photosynthetic electrons were shared between two proteins: ferredoxin-NADP+ oxidoreductase (FNR) and hydrogenase. The result was a five-fold increase in activity in that specific experiment—not five times more commercially produced hydrogen. It shows how researchers can steer electron flow, while leaving major engineering problems, especially oxygen sensitivity, unresolved.
How algae make hydrogen
Photosynthesis supplies electrons from photosystem I (PSI). In microalgae, the small protein ferredoxin carries those electrons to different destinations. One competing route involves FNR, which uses electrons to reduce NADP+ and support metabolism, including the Calvin-Benson cycle. Hydrogenase can also accept electrons from ferredoxin and use them to produce molecular hydrogen (H2).
Hydrogen production is therefore not an automatic by-product of photosynthesis. It depends on whether hydrogenase receives electrons instead of competing metabolic pathways, and on whether the enzyme remains active.
Do these 3 things before closing this tab:
1Scan for outdated or missing drivers - takes under a minute2Repair Windows errors before they cause bigger problems3Fix the driver behind crashes, sound loss and screen glitchesWhat the five-fold result means
In a 2014 study, Rumpel and colleagues used targeted variants of ferredoxin and FNR in a light-dependent competition assay. The altered protein interactions shifted electrons from PSI toward hydrogenase, producing a reported five-fold enhancement in hydrogen-evolution activity in that assay. The study abstract describes this as an activity result; it does not establish a five-fold increase in commercial output, a large-scale production rate, or a ready-to-deploy process.
#1 Best Overall
- Horizon puts renewable energy technology into the hands of our future scientists
- Solar Hydrogen Education Kit generates clean energy using the sun
- Renewable hydrogen is created using only solar energy and water
- Combining cutting-edge science, education and fun for all!
- Includes fuel cell, small electric motor, propeller blade, experiment manual and assembly guide
The underlying idea is to change the competition for ferredoxin’s electrons rather than simply assume that more light will produce more hydrogen. That distinction matters: the assay demonstrates a way to influence electron allocation, not a solution to every condition required for sustained production.
Why oxygen makes the process difficult
Photosystem II (PSII) splits water during oxygen-producing photosynthesis, providing electrons that can ultimately reach PSI. But the [FeFe]-hydrogenases used by many green algae are oxygen-sensitive. Oxygen can therefore undermine the very enzyme needed to make hydrogen while photosynthesis supplies electrons.
Rank #2
- ALGAE CULTURE: In our labs in San Diego we grow algae and zooplankton cultures for most habitats on our planet (and perhaps Mars!) We carry freshwater, brackish, marine, and extremophile cultures of algae. They grow to exhibit colorful pigments of red (phycoerythrin), orange (carotenoids), brown (fucoxanthin), blue green (phycocyanin), and our favorite->green (chlorophyll). Our algae strains have been selected because they are grown well in bottles and flasks.
- SCIENCE PROJECT: Teachers, parents, and students - grow algae easily and get great results for inquiry-based projects. Because algae grow FAST experiments take a fraction of the time as land-plants (and algae is cooler!) Great experiments: toxicology, light quality, environmental changes, algae blooms. Blog posts detail science-fair winners and other projects. Students have sent our algae into SPACE THREE TIMES (would have been four, but the rocket exploded.. we still love you Space X.)
- WHO WE ARE: Algae Research Supply is a small group of teachers and scientists with a mission of educating the next generations on aquatic science. Over 50% of the planet's oxygen comes from algae, however we are not emphasizing algae's importance in school- our mission is to make it EASY, AFFORDABLE, and REPEATABLE to teach algae in classrooms.
- WHICH ONE TO PICK: Choose from culture, culture kit, farming kits, algae beads or Brainy Briny's. All items come with our Algae Culture Manual. CULTURE is simply cells of algae. CULTURE KIT is the culture, salts, nutrients, and a flask (in most kits). FARMING KIT is used to grow batches of algae to harvest biomass. ALGAE BEADS are concentrated cells in a gel used for classrooms. Brainy Briny's are a zooplankton and algae culture kit.
Researchers face a linked set of constraints: hydrogenase needs to receive electrons, oxygen must not disable it, and PSII must remain active enough to supply electrons. Conditions that promote anaerobiosis can also impair PSII and reduce the available electron supply. Meanwhile, carbon fixation and other metabolic pathways compete for electrons.
Free tools Windows power users keep installed
One-click scans. No signup required.
Other approaches change the balance differently
Pulsed illumination
Rather than modifying protein interactions, researchers have tested light schedules that alter electron flow and oxygen balance. A 2020 study of Chlamydomonas reinhardtii used one-second light pulses separated by nine-second dark periods. In that experimental setup, the authors reported sustained hydrogen photoproduction and interpreted the pulse pattern as avoiding activation of the Calvin-Benson-Bassham cycle, directing more photosynthetic electrons toward hydrogenase. They reported that sustained production in the tested algae depended primarily on direct water biophotolysis, with PSII supplying electrons. These timing and mechanistic findings apply to that system, not to every algal strain or cultivation setup. The 2020 paper is available through PubMed Central.
Rank #3
- HANDS-ON WATER FILTRATION: Kids can build their own water filtration and distillation plant, providing a practical understanding of how clean water is produced and the science behind water purification.
- SOLAR POWER DISINFECTION: The kit teaches children how to disinfect water using solar power, promoting renewable energy concepts and demonstrating sustainable practices in water resource management.
- COMPREHENSIVE EXPERIMENTATION: Includes a detailed booklet with suggested experiments and activities, allowing for a variety of hands-on learning experiences that reinforce the principles of clean water science.
- ENVIRONMENTAL AWARENESS: Features alarming water facts that educate children about environmental issues and the importance of protecting clean water resources, fostering a sense of responsibility toward the planet.
- PERFECT FOR ALL SETTINGS: The kit includes clear instructions and all necessary materials, making it simple for children to conduct experiments safely and effectively. STEM powered learning.
A 2018 paper also discusses pulsed strong light over darkness or low background illumination as a way to redirect electron flow away from carbon fixation. This is a process-design approach, distinct from the 2014 protein-variant competition assay. The paper appears in Energy & Environmental Science.
Sulfur deprivation and mutant strains
A 2024 review summarizes other interventions under particular experimental conditions. It reports that a Y67A Rubisco mutant produced 10–15 times more photosynthetic H2 than wild type under sulfur deprivation. The review also summarizes approximately 850 mL H2 per liter of culture for sulfur-deprived Δpgr5 Chlamydomonas, and approximately 900 mL per liter for Δpgr5 with LHCA2 deficiency in the cited sulfur-deprived research. The review says the precise mechanism behind the latter result remains uncertain. These are distinct interventions and conditions, not results of the 2014 assay or directly comparable product-performance figures. Wei and colleagues’ 2024 review discusses these approaches.
Rank #4
- ALGAE CULTURE: Grown in laboratory settings in San Diego, these algae and zooplankton strains represent a wide range of habitats including freshwater, brackish, marine, and extreme environments. Cultures display vibrant natural pigments such as red (phycoerythrin), orange (carotenoids), brown (fucoxanthin), blue-green (phycocyanin), and green (chlorophyll). These strains are selected for reliable growth in bottles and flasks.
- SCIENCE PROJECT: Teachers, parents, and students - grow algae easily and get great results for inquiry-based projects. Because algae grow FAST experiments take a fraction of the time as land-plants (and algae is cooler!) Great experiments: toxicology, light quality, environmental changes, algae blooms. Blog posts detail science-fair winners and other projects. Students have sent our algae into SPACE THREE TIMES (would have been four, but the rocket exploded.. we still love you Space X.)
- WHO WE ARE: Algae Research Supply is a small group of teachers and scientists with a mission of educating the next generations on aquatic science. Over 50% of the planet's oxygen comes from algae, however we are not emphasizing algae's importance in school- our mission is to make it EASY, AFFORDABLE, and REPEATABLE to teach algae in classrooms.
What the research does—and does not—show
These studies illustrate different ways to influence the balance between electron sources, competing sinks, oxygen, and hydrogenase activity. Their outcomes depend on the organism or strain, intervention, and culture conditions. A measured activity enhancement, a short-term production rate, and a total volume per culture are different kinds of results and should not be treated as interchangeable.
Outdated Drivers Are Slowing You Down
One free scan finds every outdated or missing driver and matches the right update for your exact hardware.Free scan · exact hardware matchPC Slower Than It Used to Be?
A free scan shows the junk files, broken settings and background clutter dragging Windows down - then fixes them in one click.Free scan · Windows 10 & 11The central obstacle remains the tension between oxygen-producing photosynthesis and oxygen-sensitive hydrogenase. The 2024 review concludes that photosynthetic hydrogen production by microalgae is still far from commercial viability, citing hydrogenase oxygen sensitivity, reduced PSII electron supply under some anaerobic-inducing approaches, and electron losses through the Calvin-Benson cycle. Redirecting electrons is meaningful progress in understanding and designing laboratory systems, but it does not show that algae are already an economical fuel source.
Quick Recap
Best Value
- ALGAE CULTURE: In our labs in San Diego we grow algae and zooplankton cultures for most habitats on our planet (and perhaps Mars!) We carry freshwater, brackish, marine, and extremophile cultures of algae. They grow to exhibit colorful pigments of red (phycoerythrin), orange (carotenoids), brown (fucoxanthin), blue green (phycocyanin), and our favorite->green (chlorophyll). Our algae strains have been selected because they are grown well in bottles and flasks.
- SCIENCE PROJECT: Teachers, parents, and students - grow algae easily and get great results for inquiry-based projects. Because algae grow FAST experiments take a fraction of the time as land-plants (and algae is cooler!) Great experiments: toxicology, light quality, environmental changes, algae blooms. Blog posts detail science-fair winners and other projects. Students have sent our algae into SPACE THREE TIMES (would have been four, but the rocket exploded.. we still love you Space X.)
- WHO WE ARE: Algae Research Supply is a small group of teachers and scientists with a mission of educating the next generations on aquatic science. Over 50% of the planet's oxygen comes from algae, however we are not emphasizing algae's importance in school- our mission is to make it EASY, AFFORDABLE, and REPEATABLE to teach algae in classrooms.
- WHICH ONE TO PICK: Choose from culture, culture kit, farming kits, algae beads or Brainy Briny's. All items come with our Algae Culture Manual. CULTURE is simply cells of algae. CULTURE KIT is the culture, salts, nutrients, and a flask (in most kits). FARMING KIT is used to grow batches of algae to harvest biomass. ALGAE BEADS are concentrated cells in a gel used for classrooms. Brainy Briny's are a zooplankton and algae culture kit.
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
