Arthrospira platensis
Mark Barnett

Printable Report

Ode to a Microbe

A. platensis crossword

Abstract: Society has come to associate microbes with dreadful diseases, undesirable outcasts of the domain of life. Chemicals have been devised to eradicate them, derogatory terms such as “germs” have been used to debase and propagandize against them. However, increasingly, society is recognizing the benefits of microbes, in terms of selective degradation of waste products, useful syntheses of complex compounds, especially those intended for pharmaceutical applications, and food. Arthrospira platensis is one bacterial organism, which in a twist of irony, is preyed upon by humans. And so our story unfolds…

Introduction: Known commonly as Spirulina, blue-green cyanobacteria, A. platensis has been harvested for food purposes since ancient times. It was first described in 1940, by Dangeard, a French phycologist, who received a sample from a French pharmacologist colleague, Creach, embedded with the French Army in equatorial Africa, near present-day Chad.1 Creach found little biscuits of the dried bacterial matter, known locally as Dihe, being sold in the local market place.1,2 Dihe was the hardened product of A. platensis, which was collected from mats floating on small lakes or ponds, dried, and broken into pieces for sale. However, the report went unnoticed and 25 years would pass before A. platensis was rediscovered by the Belgian botanist, J. Leonard.1

Interestingly, the Spanish conquistadors found a similar species, A. maximus, harvested from Lake Texcoco near present-day Mexico.1 The blue-green ooze was collected with fine fishing nets and incorporated into bread. The local word was tecuitlatl, which translates into “stone’s excrement.” These two instances represent the only recorded observations in which humans used microbial biomass for food consumption.

Biology: A. platensis is a blue-green photolithoautotroph, meaning it derives its energy from sunlight and uses carbon dioxide as its carbon source.2 Minerals are derived from the inorganic sources in the environment. As with other cyanobacteria, A. platensis is gram (-), exhibiting cell membrane, cell wall and outer membrane. A. platensis thrives in shallow alkaline ponds and lakes, where the pH is in the range of 9 to 11, and the salt concentration very high, on the order of 30 g/L. Such an environment is inhospitable to most other organisms and as such, A. platensis may find itself the only organism of any significance.1 The alkaline salts are typically sodium carbonate and bicarbonate which are components of volcanic ash. In terms of photosynthesis, A. platensis is prodigious in its production of oxygen. Rates of 1.2 – 2.4 g O2/m2/hr have been reported.1

The distinguishing feature of A. platensis is its helical shape. Individual cells multiply in the usual manner via cell fission. The superstructure is the helical multicellular trichome. When the trichome is mature, it breaks up into short cellular chains of 2 – 4 cells, or hormogonia.1,2 These glide away and begin new trichomes.

Ecology and Food: A. platensis is rich in easily digested protein and phytochemicals.3 The protein is considered a complete protein since it contains all the essential amino acids. With around 65% protein (dry mass) A. platensis is superior to all plant sources of proteins, although perhaps not the quality of meat.

The environmental and economic benefits of growing A. platensis can readily be illustrated when compared to primary agricultural crops. This cyanobacteria can be obtained in high yields and has minimal growth requirements. Pound for pound of protein, it takes 30 times more water to raise beef than to grow A. platensis, and roughly 8 times more for corn, soybeans and eggs.4,5 Shear volume is not the only consideration. Beef requires fresh water, whereas A. platensis may be grown using brackish and recycled water. The geographic space comparison is also striking. In terms of pounds of protein produced per acre, A. platensis is 100 times more productive than beef and more than 10 times more productive than corn or soybeans. In addition, A. platensis can be cultivated on infertile land, while the other agricultural crops have more stringent requirements. Another advantage for the cyanobacteria, A. platensis can be easily harvested, filtered and washed. Disadvantages for traditional agricultural crops include erosion, and the toxic environmental affects of pesticides and herbicides. A. platensis does not contribute to these issues.

Medicine: Rich in protein, vitamins and other important phytochemistry, A. platensis has been recently gaining the attention of medical researchers. Studies are showing that A. platensis may exhibit antiviral, anticancer, antimicrobial, and anti-inflammatory activity.6 It has also been shown to have beneficial effects on controlling cholesterol, diabetes, coronary artery disease, weight loss, and wound healing.

Conclusion: Could this ancient prokaryote hold the cures for our modern ailments? Could this little cyanobacteria help feed a hungry world as arable land and fresh water become more scarce? Microbiology is beginning to elucidate the benefits of A. platensis and as scientists learn more, it is likely this bright, blue-green bacteria will become increasingly important as a food and health supplement.

References:

[1] Ciferri, O., Microbiological Reviews, 1983, 47 (4), 551-578.

[2] Perry, J.; Staley, J.; Lory, S.; Microbial Life, Sinauer Associates, Inc., 2002, p 768.

[3] Wikipedia, http://en.wikipedia.org/wiki/Spirulina_%28dietary_supplement%29

[4] Moorhead K., Morgan, H., Spirulina: Nature’s Superfood, Nutrix, Inc. (1995).

[5] Spirulina.Com, http://www.spirulina.com/

[6] Kahn, Z., Bhadouria, P., Bisen, P., Current Pharmaceutical Biotechnology, 2005, 6, 373-379.

Arthrospira (Spirulina) Platensis

Mark Barnett
January 18, 2007

Ode to a Microbe

Microbe, microbe, spiraled your body be,
Green-blue in color, tropical water lover,
Thriving in conditions of alkalinity [1].

Stone’s excrement by Aztecs [1,2], in Africa, Dihe [1-3],
From domain Bacteria to genus Arthrospira,
Nutritious, proteinaceous, rich in phytochemistry.

Undemanding, environmentally sound,
Oxygen producer, CO2 reducer,
Energy efficient, water conserving, no loss of ground [4].

“Super food,” says WHO; considered excellent by NASA [2,4],
Whether desert locations or outer space stations,
Count on this filamentous helical cyanobacteria.

Research is just beginning; there is much more to explore.
Anti-viral, anti-cancer, memory, immunity enhancer,
Food supplement, pharmaceutical, health and wellness galore [5]!

- Mark Barnett, January 18, 2007

[1] Ciferri, O., Microbiological Reviews, 1983, 47 (4), 551-578.
[2] Wikipedia, http://en.wikipedia.org/wiki/Spirulina_%28dietary_supplement%29
[3] Perry, J.; Staley, J.; Lory, S.; Microbial Life, Sinauer Associates, Inc., 2002, p 768.
[4] Spirulina.Com, http://www.spirulina.com/
[5] Kahn, Z., Bhadouria, P., Bisen, P., Current Pharmaceutical Biotechnology, 2005, 6, 373-379.

*Disclaimer - This report was written by a student participaring in a microbiology course at the Missouri University of Science and Technology. The accuracy of the contents of this report is not guaranteed and it is recommended that you seek additional sources of information to verify the contents.

 

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