Microalgae is rich in nutrients, contains trace elements and various bioactive substances. And it have the advantages of artificial reproduction, rapid growth, short breeding cycle, so it has a broad application prospects in feilds of medicine, health care products, aquaculture baits, feed additives, chemistry and environmental protection. In recent decades, with the application of modern biotechnology and the rapid development of separation and identification technology and genetic engineering, the research ofmicroalgaehas entered into a new stage.
The culture and research of microalgae began at the end of the 18th century, mainly in freshwater algae such as Scenedesmus and Chlorella, which was used as a test material for the study of plant physiology. In 1910 Allen and Nelson began to cultivate a variety of diatoms. In 1949, Spoehr and Milner suggested using algal proteins to solve the global problem of protein shortage.
In the study of Microalgae, the below chemical compositions is the main research subjects for researchers.
Microalgae has a high protein content, which can be used as an important source of single cell protein (SCP). Microalgae protein is a high quality protein that contains all the essential amino acids required by the human body, but microalgae proteins are generally deficient in sulfur-containing amino acids such as cystine and methionine.
The total lipid content account for 1~70% of dry matter in microalgae. It is mostly fatty acid ester of glycerol. Most limnetic microalgaes contain a lot of?-linolenic acids, which mainly contain monounsaturated fatty acids, rarely contain more than three double bonds.
The content of carbohydrate in microalgae is generally less than 20%, such as Dunaliella (12% to 40%), Spirulina (about 15%), Chlorella (about 20%) and so on. The low content of starch in microalgae provides huge potential market opportunities in the development of drugs of diabetes, gastrointestinal diseases and weight-loss.
Microalgae contains more nucleic acid than most conventional feed or food, but less than other SCP sources, such as bacteria and yeast.
Vitamins and Minerals
Vitamins in microalgae cells is abundant. These vitamins are directly related to human growth. It is rare that the content of vitamin is so high in natural food. According to Gerdes, the content of VB1 in six freshwater algae species and 31 marine algae species is account for between 0.35 and 10.5 mg/kg of dry weight per gram of cells. The content of VB2 is about 40mg/kg (dry weight). The content of potassium, phosphorus, calcium, magnesium, zinc, manganese and other mineral elements in Microalgae are also high, which is more than the content of same elements in milk.
The lipophilic pigments (such as chlorophyll, carotenoids) in microalgae account for 5% of the dry weight. Microalgae mainly contain four basic pigments:chlorophyll, lutein, carotene and phycobilin. However, the content of astaxanthin in Haematococcus pluvialis is particularly high.