Production of biofuels from algae

The mechanism underlying the synthesis of oil inside algae cells has now been revealed by a team of researchers. This discovery could contribute to the development of biofuels, the researchers claim

[Translation by Dr. Nachmani Moshe]

The findings of the study, conducted by scientists from Kobe University in Japan, were published a long time ago in the scientific journal Scientific Reports.

During the XNUMXth century, the oil products industry developed at a rapid pace, a trend that led to a reduction in the sources of fossil fuels and to climate change on a global level. In order to solve these problems and promote a sustainable society that is aware of its environment, humanity must make use of renewable biomass such as plants and algae. The amount of biomass (the total mass of all organic matter) on Earth is ten times greater than the amount of energy that humanity consumes today.

About half of this biomass is grown in aquatic environments, and biomass coming from the oceans, for example, microalgae, can be used for the production of oil without using up agricultural lands and drinking water. Microalgae can be grown with the help of light, water, carbon dioxide and a small amount of minerals, and their growth rate is fast, that is, they can be used much faster than biomass growing on land. In addition, the algae can be used throughout the year, a fact that can lead to a more stable energy supply.

Many strains of algae are capable of producing large amounts of oil (lipids), but this is the first time ever that researchers have been able to reveal the metabolic changes that occur at the molecular level when lipids are produced in algae cells. Following its focus on marine microalgae, Professor Hasunuma's research group found that the strain Chlamydomonas sp. JSC4, which is a new strain of green algae found in brackish water, has the advantages of fast growth rate and high lipid content. The researchers were also able to develop a method by which they could reveal how this strain produces the oil within the cells themselves.

The researchers grew the algae in an atmosphere of carbon dioxide as the sole carbon source. Four days after the start of incubation, more than 55% of the cell weight was carbohydrate (mainly starch). When salt water was added to the incubation liquid, the research team noticed a decrease in the carbohydrate content and an increase in the lipid content, and after seven days from the start of the incubation, over 45% of the cell weight had turned into oil. This strain has a high growth rate, and the rate of lipid production in its cells in the culture solution reached a rate much higher than that of known strains. At the beginning of the incubation period, starch particles were observed inside the cells, but these particles disappeared in the salt water, and oil droplets appeared in their place.

The researchers found that the biosynthetic pathway for the production of carbohydrates slows down, while at the same time the pathway for the production of triglyceride, a main component of the oil, is accelerated. In other words, the addition of brine diverted the pathway from starch production to oil production. In addition, the researchers discovered that the activity of the enzyme responsible for breaking down the starch increases in a salt water solution. The discovery of this metabolic mechanism is not only important from a biological point of view, but it can also be used to increase the production of biofuel by improving the methods of growing algae. Based on these findings, the researchers will continue to look for additional ways to increase the production of sustainable oil with the help of the development of more efficient cultivation methods and with the help of genetic endos.