INTRODUCTION TO ALGAE:

 

INTRODUCTION

ALGAE:                                       

The term "algae," which means "seaweed" in Latin, refers to a class of basic organisms that can be single-celled or multicellular in size (Rani et al., 2017). Algae are autotrophic and are known as primary producers which have ability to produce essential sugars and oils from atmospheric carbon dioxide (Sharma et al., 2017). They are found everywhere and grows in different habitats, such as aquatic, terrestrial, as an endophyte, epiphyte or in intense condition. Additionally, they also flourish on moist soils and other moist substrata (Ścieszka et al., 2019). There are two major classes of algae: micro algae and macro algae.

 Algae have been used by people in diet for thousands of years, according to findings archaeological from Chile that date back 14,000 years. In Europe and North America, some single-celled algae that have protein 60–70% by dry weight and is eaten as food (Wells et al., 2017). Seaweed farming is becoming more prevalent over various continents, from East Asia to Europe and South America to East Africa (Camus et al., 2018).

Many secondary metabolites generated from algae are renowned for their beneficial effects on skin. Some algae species such as fucus vesiculosus extract are helpful for minimizing dark circles under the eyes (Maira et al., 2017). Arthrospira creates a protein-rich extract that is utilised as an anti-aging supplement. Some other species include Alaria esculenta, Chlorella vulgaris, Dunalailla salina, Chondrus crispus also used in cosmetic products (Rizwan et al., 2018).

Haematococcus pluvialis is a significant source of astaxanthin, a recombinant protein utilized commercially in the food, feed, nutraceutical, and cosmetics sectors. Astaxanthin is also a hormone precursor, a source of pro-vitamin A, antioxidant, UV light protector, and anti-inflammatory (Mota et al., 2022).

Some microalgae are rich in oil (upto 80% are reported) and very valuable in nature (Ramon et al., 2017). It can be converted into many types of biofuels such as bio-oil, bio-diesel, ethanol, methane, hydrogen, syngas and charcoal by using multidisciplinary conversion technology (Suganya et al., 2016).

 

Algae contains many bioactive compounds with peculiar anti-viral, anti-fungal, anti-bacterial, anti-allergic, anti-inflammatory and anti-tumors effects (Michalak et al., 2015).  Freshwater algae Chlorella vulgaris has anti-bacterial properties against both gram negative bacteria Klebsiella pneumonia and gram positive bacteria Staphylococcus aurous (Syed et al., 2015) The extract of green algae Scytosiphon sp. had a stronger anti-allergic impact than normally used anti-allergic medication (Yu et al., 2015).

Algae are used in wastewater treatment because they can utilize heavy metals and toxic materials from their surroundings, hence lessening the toxic pollutants and reduce the number of nutrients. The use of algae to clean wastewater is referred to as “phycoremeidation” (Nur & Buma, 2018).

Algae are essential to the aquatic ecosystem. It is an autotrophic creature that conduct photosynthesis to turn water and carbon dioxide into carbohydrates (Sugar) and release oxygen as a byproduct, which is vital component for survival of fishes and others aquatic fauna (Bauddh & Korstad, 2022). Due to the presence of high protein level and carbohydrates some micro and macro algae are eaten as food by aquatic organisms such as fishes, turtles and zooplanktons (Matassa et al., 2016)

The greenhouse effect, which causes global warming, has many causes, one of which is carbon dioxide. By utilizing these greenhouse gases and lowering the concentration of hazardous chemicals in the atmosphere, algae maintains a clean environment for other living organisms (Kim et al., 2020).

Agar, alginates and carrageenan are some of the most useful compound because of their gelling and thickening abilities, derived from algae (Sharma et al., 2017).Algae contain natural pigments, which are high-value metabolites such chlorophylls, phycobiliproteins and carotenoids (Lutein, B-carotene, Lycopene, Astaxanthin, Centaxanthin, Capsanthin and Zeaxanthin). Because of their bioactive and color qualities, they are used in food, fine chemicals and cosmetic sectors. Centaxanthin, Capsanthin and Lycopene are used as coloring agents in beverages and other food products (Radomska et al., 2020).

Algae is great source of dietary fibers, Proteins, enzymes, Carbohydrates, vitamin A, B1, B2, B6, B12, C, E, biotin, folic acids and nicotinamide and mineral like iodine, iron, magnesium, potassium and calcium(Goswami et al., 2015).

            Extract of algae plays important role in the field of agriculture. Green microalgae, such as Chlorella sp., Scenedesmus sp., and Acutodesmus dimorphus, have the ability to produce phytohormones, such as gibberellins, cytokinins, auxins, abscisic acid, and brassinosteroids, which act at low concentrations to stimulate plant growth and yield in a very effective way (Do et al., 2020). 0.4% Chlorella fusca culture (1.5 x 107 cells/mL) when applied to Chinese chives and spinach, it not only improved the plants' quality and growth but also lowered the risk of grey mold disease (Kim et al., 2018).

            The root system and germination rate of cucumber enhanced by the culture of salt tolerant C. pyrenoidosa (Elhafiz et al., 2015).The extract from Scenedesmus quadricauda promoted the development of lettuce seedlings (Puglisi et al., 2020). Chlamydomonus reinhardtii, a genetically altered green alga, has been used to produce human growth hormones (Wannathong et al., 2016).