The necessity and expediency of developing an effective technology for cultivation of microalgal biomass and its processing are determined by a number of key factors:
According to various sources, the world’s total identified and probable reserves of conventional and synthetic oil are estimated at 500 billion - 1.3 trillion tons.
The increasing level of consumption of natural fuel resources (oil, gas) and the reduction of their supplies pose the problem of search for new energy sources. The most promising way is to use renewable environmentally safe energy sources.
Last year emissions of carbon dioxide (CO2) into the atmosphere reached a record level of 35.6 billion tons (The International Energy Agency, the journal Nature Climate Change).
In 2010, the total greenhouse gas emissions in Russia made up 2,201,900 million tons (state report of the Ministry of Natural Resources and Environment of the Russian Federation).
In 2000-2007, the amount of the global emissions of carbon dioxide (CO2) was increasing 4 times faster than during the previous decade.
With the further development of the global industry and the growth of the world population, the amount of CO2 emissions will grow even more rapidly (The Global Carbon Project report).
In the near future, due to the intensification of the process of industrial biological photosynthesis, carbon dioxide (CO2) will turn from a source of pollution into the main constantly renewable resource for the industrial production of biofuels, protein, and other products.
Given the enormous promise and importance of this task, all developed countries and the world’s largest corporations are conducting intensive work in this field.
The energy obtained while using fossil fuels (coal, oil, natural gas, peat) was previously produced in the process of photosynthesis and accumulated in these wildlife products.
Photosynthesis - is the formation of an organic substance from inorganic ones (carbon dioxide and water) in the light with the participation of photosynthesizing pigments.
This is the only biologic process, which is accompanied by an increase of the free energy of the system.
Previously, the use of photosynthesizing biomass of different crops (corn, wheat, jatropha, rapeseed, oil palm, sunflower, miscanthus, etc.) was considered as promising renewable sources of raw materials for biofuel production.
However, this way entails serious problems as it requires a significant increase in acreage and consumption of freshwater.
According to the estimates, the needs of only the U.S. for biofuels can be fully met by harvesting corn from fields with the area of 820 thousand square miles, which is comparable with the entire Midwest United States. Increased global production of biofuel will require substantial transformation of agriculture and large-scale felling of forests, including those in the basins of tropical rivers.
Cutting down forests for planting “biofuel crops” results in climate change and serious environmental problems.
But according to the world’s leading scientists, the main factor in the long-term outlook determining the impossibility of biodiesel production from the “land fuel crops” to substantially replace petroleum is the limited freshwater resources on the planet.
The most promising renewable crop which has the highest rate of biomass photosynthesis is microalgae. They provide a 4-fold increase in biomass amount per a day and reduce the amounts of carbon dioxide in the atmosphere and nitrogen in wastewater. They have the most effective natural apparatus for solar energy bioconversion.
There are almost unlimited resources for production of microalgal biomass such as sunlight, CO2 emitted as a result of various processes, wastewater, polluted waters of seas and lakes.
The problems of utilization of surplus CO2 and partial biological wastewater treatment are simultaneously solved, the consumption of freshwater does not increase and it is not removed from the natural water cycle, arable land is not used, forests are not cut down, and the ecological balance disturbed by human technogenic activities is partially restored.
The production of 1 kg of microalgal biomass requires 1.83 kg of CO2.
Oil and energy contents in different crops
(average oil energy content of crops is assumed to be 35.5 kJ /g)
As it can be seen from the table, microalgae significantly (tenfold) surpass oil palm, rapeseed, jatropha and other crops by energy output.
Biofuel produced from microalgae is considered by many world experts to be an alternative to the “petroleum” fuel.
If efficient apparatuses and technology are created, the use of a region comparable to the North Sea in size for microalgae cultivation would allow us to generate fuel sufficient to meet the needs of transport systems of the whole planet (nzherald.co.nz).
Large amounts of other useful products such as food and feed protein, antioxidants, biologically active substances, food colorants, etc. could be produced from microalgae.
Protein derived from microalgae can become an alternative to soy protein.
The global demand for soybeans is currently estimated at about 150 million tons a year.
As 99% of the grown soybeans are genetically modified while the EU Environmental Code has legally stated that food products cannot contain genetically modified organisms (GMOs), algal protein has a great potential for successful introduction to the global market of both food and feed protein.
The need of the Russian agriculture for feed protein is estimated by various sources at 5-8 million tons/year. Most of it is purchased abroad.
One hectare used for algae cultivation yields the same amount of protein a year as 21 hectares of soybeans and 49 hectares of corn.
Table 2: Comparison of yields
Microalgae have high nutritional value and significantly surpass all feed crops by protein and carbohydrate content.
Table 3: The comparison of nutritional values: microalgae and soybeans
Deriving products for human food and animal feed from microalgae has a high economic and investment attractiveness.