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Microalgae and Diatoms – Prospect New Energy Source and More

                                                                                                 Stones covered with algae along the shore / Photo by Pixabay

 

Photosynthetic marine organisms may soon pave the way to further allocate renewable energy source. In addition, valuable natural products made involving these aquatic microorganisms may also be discovered as researches on diatoms and microalgae establish astounding feats on technology and other applications.  

 

Algae as a Source of Fuel

Diatoms have played a decisive role in the ecosystem for millions of years as one of the foremost set of oxygen synthesizers on earth and as one of the most important sources of biomass in oceans. Previously, diatoms have been almost exclusively limited to academic research but efforts have been made to establish them as useful in such commercial and industrial applications as the carbon neutral synthesis of fuels, pharmaceuticals, health foods, biomolecules, materials relevant to nanotechnology, and bioremediators of contaminated water. Progress in the technologies of diatom molecular biology such as genome projects from model organisms, as well as culturing conditions and photobioreactor efficiency, may be able to be combined in the near future to make diatoms a lucrative source of novel substances with widespread relevance.
 

As with diatoms, microalgae became increasingly interesting during the last decades as many of these organisms provide valuable natural products. Especially the high lipid content of some species currently attracting attention in the biodiesel industry. A further application that emerged some years ago is the use of microalgae as an expression platform for recombinant proteins. Several projects on the production of therapeutics, vaccines, and feed supplements demonstrated the great potential of using microalgae as a novel low-cost expression platform.

On a study by Dr. Hempel, the diatom Phaeodactylum tricornutum exhibited as bioreactors for the production of therapeutic proteins like antibodies and vaccines, polymers such as the bioplastic PHB and other biotechnologically relevant materials revealing the great potential of these microalgae as solar-powered microfactories.

Microalgae have enormous potential for diverse biotechnological applications and currently attract much attention in the biofuel sector. Still underestimated, though, is the idea of using microalgae as an expression system for the production of recombinant proteins. Microalgae combine rapid growth rates with all the advantages of eukaryotic expression systems and offer great potential for solar-powered, low-cost production of pharmaceutical proteins.

Dr. Hempel also concluded in the study that Diatoms are naturally rich in lipids and silicate and already have applications in biotechnology. Hence, inserting and/or altering biochemical pathways in diatoms in order to synthesize complex molecules, biologically active substances, and raw materials may have a number of applications in for example the nanotechnology industry and the production of renewable biofuels.

The BioEnergy science center also focuses on understanding lignocellulosic biomass formation and deconstruction en route to the production of biofuels.  This deeper understanding of plant cell wall structure and the biological mechanism for efficient depolymerization and fermentation was necessary to provide the underpinnings to “overcome biomass recalcitrance”.

 

 

A Substitute for Fossil Fuel

In the research to displace fossil fuels, algae feedstock has emerged as a suitable candidate not only because of its renewable and sustainable features but also for its economic credibility to produce renewable fuel. Biomass or algae feedstock is very easy to cultivate and it has the capability to match up to the increasing global demand for transportation fuel.   

Dave Hazlebeck, CEO of Global Algae Innovations, explained how his company is revolutionizing sustainable energy. "The fuel that we're producing is exactly the same in terms of performance as gasoline or diesel or jet, it's just a lot cleaner. I think the big difference is that [with] all the other biofuels, you're growing it and you're just getting biofuel. In this case, for every gallon of biofuel you get 10 pounds of food with it," Hazlebeck said.

Hazlebeck believes his company is on the path to completely change the way we currently produce both oil and food. Not only can algae create biofuel, it can also be used to create animal feed. Currently, most animal and fish feed is made from corn or soy, which both use more water and energy to grow than algae.

Algae can be used to create food for humans as well. New Wave Foods in Northern California created fake shrimp made from algae and other plants that actually looks, smells and even tastes like real shrimp. Because it's made from algae, the shrimp substitute also has the added benefit of being low in fat and extremely rich in nutrients, something that corn and soy are severely lacking.

One of the issues experienced that allow setbacks for the company is Cost. When Global Algae Innovations began, a gallon of oil produced from algae was about $30 a gallon -- 10 times higher than it needs to be to work as a viable alternative to fossil fuel. But Hazlebeck and his team didn't give up, and they've continued to come up with solutions to decrease the cost. As of now, they almost have algae oil down to only $2 - $3 a gallon.

 

Decades of ecological research have demonstrated that plant and animal communities containing a rich mix of species are, on average, more productive than less-diverse communities, more stable in the face of environmental fluctuations, and more resistant to pests and diseases.

Consequently, bioplastics are a feasible alternative to this source in that they are not based on fossil resources and can easily be biodegraded. So far, however, production costs for petroleum-derived polymers still remain lower than biodegradable alternatives, which is a hindrance to commercial development and retail of environmentally friendly alternatives.

As stated from biomass magazine, an outdoor study by University of Michigan (U-M) researchers grew various combinations of freshwater algal species in 80 artificial ponds.

Overall, the researchers found that diverse mixes of algal species, known as polycultures, performed more key functions at higher levels than any single species—they were better at multitasking. But surprisingly, the researchers also found that polycultures did not produce more algal mass, known as biomass, than the most productive single species, or monoculture.

"The results are key for the design of sustainable biofuel systems because they show that while a monoculture may be the optimal choice for maximizing short-term algae production, polycultures offer a more stable crop over longer periods of time," said study lead author Casey Godwin, a postdoctoral research fellow at U-M's School for Environment and Sustainability.

In both phases of the study, colleagues at the U-M College of Engineering used a technique called hydrothermal liquefaction to convert the algae into combustible oils, or biocrude, which can be refined to make transportation fuels like biodiesel.

"First we evaluated different combinations of algae in the lab, and then we brought the best ones out to nature, where they were exposed to fluctuating weather conditions, pests, disease and all the other factors that have plagued algae-based fuel research efforts for 40 years," Godwin said.

In the classical approach to using algal biomass as a feedstock for biofuel production, the lipids are extracted and upgraded to biodiesel or renewable diesel/jet fuel.  Microalgal biomass is well suited for this sort of process because under the right cultivation conditions, it can contain more than 50% lipids by weight. However, even at this high lipid content, 50% of the biomass (largely protein and carbohydrate) is wasted.  This residual biomass is sent to anaerobic digesters for conversion to biogas which can be used to generate heat and power for the biorefinery and to provide a means to recycle nutrients back into the ponds. Although this can improve the sustainability of the process by reducing the amount of fossil fuels needed for heat and power, biogas adds little to the overall economics due to low value in the face of cheap, readily available natural gas.

 

Algae-derived biocrude oil is being studied as a potential renewable-energy alternative to fossil fuels. Because they grow quickly and can be converted to bio-oil, algae have the potential to generate more fuel from less surface area than crops like corn. But the technical challenges involved in growing vast amounts of these microscopic aquatic plants in large outdoor culture ponds have slowed progress toward commercial-scale cultivation.

 

Biofuels and Other Applications

ExxonMobil Research and Engineering Company envision to create biofuel on a major scale.

In seven years, with some assumptions about continued advancements in their ability to gene-edit and farm algae, they believe that they will be technically able to produce 10,000 barrels of algae biofuel a day. That’s a tiny amount compared to crude production; the U.S. may soon produce as much as 11 million barrels a day.“The goal here is to get to a sustainable, renewable biofuel that can be cost-competitive with pumping oil out of the ground, but can scale to levels that go far beyond demonstration levels,” says Oliver Fetzer, chief executive officer at Synthetic Genomics. “We see this step as a very important step along the way to scalability.”

While a truck running on biofuel still emits greenhouse gases, the emissions can be considered carbon neutral since the algae suck up CO2 as it grows–unlike fossil fuels, which burn carbon that has been buried for millions of years.

Algae applications are evident for everyday consumption via foods products, non-foods products, fuel, and energy. Biofuels derived from algae have no impact on the environment and the food supply unlike biofuels produced from crops.

 

                                                                                                 Algae biofuel inside a lab / Photo by Shutterstock

 

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