Algae Provides Sustainable Nutrition for the 100-Year Starship
February 15, 2012
ur human body consists of roughly 100 trillion cells organized biologically. Each cell must be supplied with the nutrients required to sustain life. Metabolism causes the body to consume some of its mineral elements and vitamins in order to neutralize cellular and tissue wastes for excretion by the skin, lungs, kidneys, and bowels.
Humans, animals, and plants require a continuous nutrient replenishment. The body can assimilate extra supplies of vitamin-rich and mineral-rich foods. However, assimilation occurs only when sufficient levels of each nutrient are present in the food, feed, or fertilizer. Algae grown in starship microfarms recycle waste streams and carry all the essential nutrients necessary for sustaining metabolism.
Some of the elements present in the human body are found only in minute fractions, while others occur in larger percentages. The muscles, bones, blood, and some other tissues and fluids contain higher percentages of oxygen, carbon, hydrogen, and nitrogen. The human body requires the nutrients shown in the table 1, which makes recovering these nutrients efficiently mission critical.
Human Body Constituents In a normal person weighing 60 kg
|Constituent||Constituent Weight||Percent of atoms|
|Oxygen||38 kg||25.5 %|
Even though the body’s need for trace elements such as iodine and zinc are tiny, they are critical. Insufficient zinc causes hypozincemia that disrupts cellular metabolism. Zinc deficiency can cause mental impairment, memory loss, loss of eyesight and taste, major organ malfunction, congenital abnormalities, hair loss, acne, skin lesions, diarrhea, and wasting of body tissues.
The human body also needs vitamins, trace elements, and antioxidants. The five most prevalent public health diseases globally are malnutrition, nutritional anemia, (iron and B12 deficiency), xerophthalmia (vitamin A deficiency), endemic goiter, (iodine deficiency) and zinc deficiency. The FAO estimates that as many as 60% of people globally are threatened by one or more of these maladies. These diseases can be avoided on the starship because algae naturally provide the full spectrum of macro and micronutrients that avoid malnutrition and nutrient deficiencies.
Nutrient recovery sources include gasses given off by human, animal, and plant breathing, belching, flatulence, transpiration, and metabolism. The airborne methane, acetone, methyl alcohol, ammonia, and carbon dioxide are recovered by bubbling starship air through smart microfarms, which allow algae to act as natural scrubbers that capture CO2 and other gases continuously. The process returns pure oxygen to the starship air system. Microfarms bubble the gases to mix the algae culture, which gives all the cells access to their energy source – light and photons.
This flat plate microfarm, located at the ASU Laboratory for Algae Biotechnology Research, bubbles CO2 and air to mix the culture. This section links in series to other sections in a row that maximizes culture growth and productivity. Cultures change color with maturity, similar to the color change of fall leaves.
Excreted nutrients are recovered using the two-hole toilet, developed in Sweden, that separates liquid and solid wastes. The system exposes excrement and other wastes to UV light and/or solar heaters to eliminate parasites and pathogens.
Animal and botanical wastes are ground up and returned to the algae culture, where those nutrients are recycled to various forms of green biomass. Some botanical wastes are recycled through ruminants aboard, including goats and llamas. Ruminant stomachs also provide a rich natural storage system for useful microflora.
Crewmember clothing, made of biodegradable algatex textiles, is similarly recycled for recoverable nutrients. Starship internal structures, made out of various algae-based materials, are recycled for nutrient recovery when they near the end of their usefulness. The nutrient recovery process grinds wastes into nanoparticles that an algae culture can absorb. Alternatively, gasification, (pyrolysis), burns the organic materials and the nutrients are delivered to algae in the form of absorbable gases. Gasification recycling requires closed microfarms because the bubbled gases must be recycled. Algae cultures can capture all the ambient gases when the gases are recycled.
Algae probably served as the first convenience food for our pre-human ancestors as the biomass grew abundantly and was easy to harvest. Humans evolved around the Rift Valley Lakes in East Africa where Lucy and other early human fossils have been found. The Rift Valley Lakes continue to produce large quantities of the algae most commonly used as a health food and food supplement today – spirulina. Spirulina and other algae species probably served as food and medicine for early humans.
Algae grow at the bottom of the food chain and provide a rich and nearly complete source of nutrition with a complex blend of nutrients that no other food source, plant or animal offers. Algae contain far higher nutralence – nutrient diversity and density – than modern land-based foods. Algae contain a broad spectrum of prophylactic and therapeutic factors that include vitamins, minerals, amino acids, essential fatty acids, the super anti-oxidants such as beta-carotene, vitamins E and C, and selenium, and a number of unexplored bioactive compounds.
Since these many constituents stimulate numerous metabolic pathways, algae has been demonstrated to promote antioxidant, anti-bacterial, antiviral, anticancer, anti-inflammatory, anti-allergic, and anti-diabetic actions, as well as vascular, mental, and intestinal health. Algae can be considered analogous to a modern-day vitamin supplement. Algae offer a more robust, natural, bioavailable, and inclusive blend of healthful compounds than supplements.
Algae are a superior protein source among plant foods, particularly the red, green and blue-green algae, which are as high as 70% protein dry weight. Algae offer roughly three times more protein per gram than corn. Algae are also an excellent plant source of glutamic acid, an amino acid that promotes intestinal health and immune function.
Although very low in fat, algae offer an excellent source of the essential polyunsaturated fatty acids. The omega-6 and omega-3 fatty acids (ARA and EPA/DHA respectively) are necessary for normal metabolism as they are the precursors to critical hormone-like, signaling molecules known as the eicosanoids. These short-lived messengers direct life-supporting functions such as blood clotting, inflammation, vasodilation, blood pressure, and immune function.
Small amounts of ARA and EPA/DHA are needed daily (<1 g), and one tablespoon of dried algae can supply about half this amount. Unlike most other land plants and animal foods, the omega-6:3 ratio is <1, a highly desired characteristic since ratios <1 are most healthful for humans.
Algae can sustain human, animal, and plant nutrition on the starship because algae have the capacity to recycle and repurpose nutrients efficiently. Nutrients continually support the growth of new algae biomass, from which valuable compounds for human consumptions such as protein, vitamins, and omega-3 and omega-6 fatty acids.
Currently, most of the omega oils are derived from fish. Fish do not synthesize omega oils, they obtain them from the algae in their diet. Omega oils produced from the natural source, algae, will reduce the pressure on the ocean food chain, and create higher quality nutraceuticals without a fishy taste or mercury residue.
The starship nutrient recovery process provides an achievable model for human societies on Earth. Either we learn to recover, recycle and repurpose nutrients from our mammoth waste streams, or our children will have no natural resources. We need to begin the process of systemic nutrient regeneration now!