614
R. Pangestuti et al.
which use Chlorella spp. as carotenoid source which has a function to stimulate
collagen production naturally (Ryu et al. 2015). Nowadays microalgae extracts are
frequently found in cosmetics and skin care products as thickening agents, antiaging
cream, antioxidants, and colorant of make-up products (Priyadarshani and Rath 2012)
Microalgae are also found in UV-protection and hair treatment products.
25.1.2 Microalgae Growth Condition
Microalgae have an efficient and simple metabolism as advantages of becoming
unicellular species. Because of that reason, microalgae can grow rapidly and become
the fastest growing organism in this Earth. Most of the microalgae reproduce vegetatively by binary division several times depending on the species and environmental
conditions. Some species of dinoflagellates takes two or more days to doubling the
cell number, and shorter for cyanobacteria (blue-green algae) in which doubling
takes place more than once a day (Blackburn and Parker 2005). Living with simple
physiological metabolism, microalgae is adapted in extreme environmental conditions such as extreme temperature (heat or cold), anaerobes, high or low salinity, UV
exposure, and pollution (Singh et al. 2019).
Even though microalgae has simple metabolism it needs several requirements
to keep living. Basic growth requirements are different among autotrophic and
heterotrophic microalgae. As a photosynthetic organism, autotrophic microalgae
absolutely need light and CO 2 to perform photosynthesis to gain energy.
Heterotrophic microalgae can use another organic carbon source. Apart from them,
environmental parameters are important to microalgae growth such as, light intensity
and wavelength, temperature, salinity, nutrient, and chemical contains. In cultured
microalgae, these parameters can be manipulated to gain specific condition. For
example, in some microalgae, salinity stress can improve lipid production. Different
light wavelengths also effect lipid and pigment production.
Microalgae can be cultured in large scale using two main systems, open air system
and photobioreactors (Borowitzka 1999). The uses of these systems are depending
on cultured species characteristics, sunlight intensity, climate condition, nutrient and
CO 2 supply, and the end product type. In open air system, contamination is one of
the main problem in single species culture. Some algal species such as Spirulina
and Chlorella, require specific culture condition, so that these species are a perfect
example of species that are commonly cultured in open air system because other
microalgae species are hardly contaminating this specific conditions (Wang et al.
2008). Open air system costs lower, and less complex in its construction. This system
is perfectly used in tropical area with long beach line, where the climate is stable
and humidity is consistent. Open air system also has some disadvantages such as
water loss from evaporation that cause increase in salinity. The construction also
needs more attention, it has to be shallow enough so that sunlight can not only reach
the deeper cell, but also has to be deep enough to complete mixing. The biomass
produced by this system is relatively lower than closed system, roughly 0.1–0.5 g
R. Pangestuti et al.
which use Chlorella spp. as carotenoid source which has a function to stimulate
collagen production naturally (Ryu et al. 2015). Nowadays microalgae extracts are
frequently found in cosmetics and skin care products as thickening agents, antiaging
cream, antioxidants, and colorant of make-up products (Priyadarshani and Rath 2012)
Microalgae are also found in UV-protection and hair treatment products.
25.1.2 Microalgae Growth Condition
Microalgae have an efficient and simple metabolism as advantages of becoming
unicellular species. Because of that reason, microalgae can grow rapidly and become
the fastest growing organism in this Earth. Most of the microalgae reproduce vegetatively by binary division several times depending on the species and environmental
conditions. Some species of dinoflagellates takes two or more days to doubling the
cell number, and shorter for cyanobacteria (blue-green algae) in which doubling
takes place more than once a day (Blackburn and Parker 2005). Living with simple
physiological metabolism, microalgae is adapted in extreme environmental conditions such as extreme temperature (heat or cold), anaerobes, high or low salinity, UV
exposure, and pollution (Singh et al. 2019).
Even though microalgae has simple metabolism it needs several requirements
to keep living. Basic growth requirements are different among autotrophic and
heterotrophic microalgae. As a photosynthetic organism, autotrophic microalgae
absolutely need light and CO 2 to perform photosynthesis to gain energy.
Heterotrophic microalgae can use another organic carbon source. Apart from them,
environmental parameters are important to microalgae growth such as, light intensity
and wavelength, temperature, salinity, nutrient, and chemical contains. In cultured
microalgae, these parameters can be manipulated to gain specific condition. For
example, in some microalgae, salinity stress can improve lipid production. Different
light wavelengths also effect lipid and pigment production.
Microalgae can be cultured in large scale using two main systems, open air system
and photobioreactors (Borowitzka 1999). The uses of these systems are depending
on cultured species characteristics, sunlight intensity, climate condition, nutrient and
CO 2 supply, and the end product type. In open air system, contamination is one of
the main problem in single species culture. Some algal species such as Spirulina
and Chlorella, require specific culture condition, so that these species are a perfect
example of species that are commonly cultured in open air system because other
microalgae species are hardly contaminating this specific conditions (Wang et al.
2008). Open air system costs lower, and less complex in its construction. This system
is perfectly used in tropical area with long beach line, where the climate is stable
and humidity is consistent. Open air system also has some disadvantages such as
water loss from evaporation that cause increase in salinity. The construction also
needs more attention, it has to be shallow enough so that sunlight can not only reach
the deeper cell, but also has to be deep enough to complete mixing. The biomass
produced by this system is relatively lower than closed system, roughly 0.1–0.5 g