Ideal culture conditions to grow Algae

Algae are green plants, primarily they requires sunlight, carbon dioxide and mineral nutrients. On the other hand they also requires optimum environmental conditions such as the right pH and temperature. Algae grow and thrive mostly in water and moist environmental conditions. Depending on the algae species, algae can grow either in fresh water or sea water. The majority of microalgae thrive in fresh water, though many micro algae can grow also in sea waters too. Most of the macroalgae are the dominant types of green plants in the seas and oceans.

Sunlight requirements

Algae which lives in deep waters require very low intensity of sunlight, but algae species which lives on the surface of the water or in a very shallow waters require direct sunlight. In most modern photobioreactors light is provided artificially from fluorescent lamps. This kind of lamps are good option to control the intensity of light based on the particular species of algae.

Carbon dioxide and other gases

Algae consumes very huge amount of carbon dioxide, than terrestrial green plants. For algae cultured under photo bioreactors and open ponds, carbon dioxide is supplied artificially in the form of bubbles. The optimum concentration of carbon dioxide to grow algae for biodiesel purpose is up to 3%.
Oxygen is the byproduct of photosynthesis as a result very high concentration of oxygen in the water can be toxic to the algae for it reduces photosynthesis efficiency. To avoid oxygen toxicity the water should be constantly stirred and recycled to remove the excess oxygen.
Some photobioreactiors get their carbon dioxide from flue gas. This type of gas contain up to 15% of carbon dioxide. In addition to this it is also a mixture of many other gases such as nitrogen dioxide, sulphur dioxide, etc. Most algae can make use of this extra mixture of gases as a nutrient sources.

Mineral nutrients, Vitamins, and hormonal requirements

Because of the diverse nature of algae species in their nutrient requirements, it is very difficult to generalize the amount and rate of each nutrient required by algae. But most scientists agree that all algae needs a set of 14 elements, these are Nitrogen, Phosphorus, Magnesium, Potassium, Sulphur, Calcium, Molibdium, Zinc, Iron, Copper, Manganese, Oxygen, Hydrogen and Carbon. In addition, some elements are required by some or more algae, these are Cobalt, Iodine, Sodium, Boron, Chlorine, Silicon and Bromine. For example diatoms need an additional silicon for optimum growth. All algae uptake dissolved inorganic nutrients such as nitrates, nitrites, ammonium and phosphates.

Vitamins such as vitamin B12 and thiamine and growth regulators could give better yield of algae. The concentration of the vitamins and growth regulators and the method of applications will depend on the particular species of algae.

pH requirements

The ideal pH for most algae species is between 7 to 9 pH levels. The culture medium should be kept alkaline with an average pH of 8. Most algae are very sensitive to acidic culture medium and they perform very badly under acidic conditions.

Nutritional and Health benefits of algae

Many species of algae have been identified and used as a food and food additives. Algae are a very nutritious food source, which have a long list of health benefits. Species of algae such as Spirulina, Chlorella, Aphanizomenon and Scenedesmus are some of the species of microalgae that have very high nutritional and health benefits.

Spirulina are the most nutritious of all the other species of algae. They are also the most widely grown algae by food industries. Spirulina are blue green microalgae. They can grow in both fresh waters and salt waters. Spirulina contain as high as 70% of proteins, all the spectrum of the vitamin B complexes including vitamin B-12, vitamin A, and vitamin C, antioxidants such as phenolic acids, alpha-carotene and beta-carotene. They also contain different mineral elements such as calcium, magnesium, iron, phosphorus and potassium. Eating spirulina regularly has a lot of health benefits such as prevention and healing of protein malnutrition, healing and immunity from anemia, alleviation of indigestion, glaucoma, cataract and night blindness. They benefit the health by increasing blood hemoglobin, by controlling and prevention of diabetes, pancreatitis, cirrhosis, hepatitis and cancerous cells. Because of their richness in vitamin E, use of cosmetic products made from Spirulina, will improve skin health and appearance. It also heals wounds when applied on cuts. It increases lactation in nursing mothers. It reduces blood sugar and cholesterol levels too.

Chlorella are also microalgae. They are considered the second most nutritious species of algae. Chlorella are green algae, they are almost comparable in their nutritious content with Spirulina, but with slightly less protein content than Spirulina. Chlorella have very high nucleic acid and chlorophyll content. Nucleic acid will help to reduce aging, facilitates cell renewal and growth. Chlorophyll has health benefits by causing cell renewal and growth, wound healing, prevention of infections, removal of bad breath and body odor, anti-inflammation and increases the availability of vitamins A, E, and K. Chlorella are rich with antioxidants, which act as antiaging and wound healer. They are very effective to reduce cholesterol and body fat.

Aphanizomenon are also blue green microalgae like Spirulina, having both nutritional and health benefits. Even though Aphanizomenon are very nutritious and have a lot of health benefits they should be grown or cultured with upmost care by supplying all the optimal growth conditions such as light, water and mineral nutrients, because if they grew under stress conditions they can be extremely lethal poison.   

Scenedesmus are green microalgae. They have up to 60% of protein content, more than that of soybeans. They also contain the whole set of vitamin B complex including vitamin B 12 and vitamin C, more than that of an egg. Due to their high nutritional content they are used to restore to health malnourished children. But daily intake of Scenedesmus should be below 20 to 35 g of dry weight since they have the ability to raise uric acid level enormously.