Microalgal Biomass Production 71
compounds along with the induction of behavioral processes such as prey catching, regulation of
bacterial community, probiotic effects and the stimulation of immunity were controlled (Hong et al. 2005;
Raja and Hemaiswarya 2010). Several factors contributing nutritional value of a microalga (it includes
their size and shape, digestibility, biochemical composition, enzymes, toxins and the requirements of
animal feeding on the alga). Studies have tried to correlate nutritional value of microalgae with their
biochemical profile (Richmond 2004; Durmaz 2007). However, results from feeding experiments that
have examined microalgae which are contrary in a specific nutrient are challenging to interpret because
of the confounding effects of other microalgal nutrients. Nevertheless, from examining the literature,
algal foods have been enhanced with compounded diets or emulsions, some general conclusions can be
reached (Knauer and Southgate 1999).
Algae grown to late logarithmic growth phase typically contain 30–40% protein, 10–20% lipid
and 5–15% carbohydrate (Fujii et al. 2010). In stationary phase, composition of microalgae can change
significantly for example, when nitrate is limiting, carbohydrate levels can double at the expense of protein
(Liang et al. 2009). There does not appear to be a strong correlation between the proximate composition
and nutritional value, though algal diets with high levels of carbohydrate are stated to produce the best
growth for juvenile oysters, Ostrea edulis (Ponis et al. 2006). Larval scallops, Patinopecten yessoensis
provided polyunsaturated fatty acids in adequate proportions. In contrast, high dietary protein provided
best growth for juvenile mussels, Mytilus trossulus and Pacific oysters, Crassostrea gigas (Knuckey et
al. 2002).
Algal pigments transferred to zooplankton may contribute to nutritional value (Lorenz and Cysewski
2000; Gagneux-Moreaux et al. 2007; Raja et al. 2008). Dominant pigments in the copepod, Temora sp.
are lutein and astaxanthin whereas in Artemia it was canthaxanthin (Kang and Sim 2008; Gentsch et al.
2009), these prey items were fed to halibut larvae adequate amounts of vitamin A were found in halibut
fed on copepods but not with halibut fed on Artemia. It was suggested that Artemia should routinely be
enriched with astaxanthin and lutein to improve their nutritional value. Astaxanthin and canthaxanthin
are the only pigments that can fix in the flesh of salmonids whose pinkening represents a 100 million
US$, rapidly expanding market (Raja et al. 2007c). This feed additive is produced by chemical synthesis
and available at a price of 3000 US$/kg approximately. The biological sources for astaxanthin are the
yeast, Phaffia rhodozyma (Sanderson and Jolly 1994) despite its low content (0.4%), and compared to
Haematococcus pluvialis containing 5% (Guerin et al. 2003; Kang and Sim 2008).
Some companies like Algatec-Sweden, Norbio-Norway, Biotechna-UK, Aquasearch, Cyanotech,
Maricultura, Danisco Biotechnology and Oceancolor-USA have entered the astaxanthin market. In fact,
microalgal astaxanthin has been approved in Japan and Canada as a pigment in salmonid feeds (Spolaore
et al. 2006). Feeds including 5–20% Arthrospira sp. (rich in carotene pigments), to enhance the red and
yellow patterns in carp. This clarity and color description increases their value. Another example is the
traditional French technique so-called the greening of oysters. It consists of creating a blue-green color on
the gills and labial palps of oysters using the diatom, Haslea ostrearia, it increases the product’s market
by 40% (Gagneux-Moreaux et al. 2007). For vaccine purpose Chlamydomonas sp. has been used using
the p57 antigen, the causative agent of bacterial kidney disease. This disease is caused by the intracellular
bacterium, Reinbacterium salmoninarum which affects wild and farmed salmonids. A huge concern from
an economic point of view and the symptom of disease which develops before it can be treated with
antibiotics. Fish-fed algae (4% algal dry weight of feed) fed to juvenile trout produced immunoglobulin
IgM expressed in different tissues (epithelial or blood cells).
Animal feed and aquaculture
The increased shrimp farming production mainly takes place in subtropical regions of America and
South-East Asia (72%, 3,718 hatcheries) (Alam et al. 2009). Microalgae are being in use to improve the
nutritional quality and gives coloration to the shrimps. Among these Chlorella grows in nutrient-rich
media, while Spirulina sp. requires a high pH of 9.5–11 with appropriate concentration of bicarbonate.
Similarly, Dunaliella salina grows at the high salinity of 0.5–6 M (Raja 2007b). Several algae such as
Chaetoceros sp., Isochrysis sp., Skeletonema sp., Thalassiosira sp., Tetraselmis sp. and Crypthecodinium
compounds along with the induction of behavioral processes such as prey catching, regulation of
bacterial community, probiotic effects and the stimulation of immunity were controlled (Hong et al. 2005;
Raja and Hemaiswarya 2010). Several factors contributing nutritional value of a microalga (it includes
their size and shape, digestibility, biochemical composition, enzymes, toxins and the requirements of
animal feeding on the alga). Studies have tried to correlate nutritional value of microalgae with their
biochemical profile (Richmond 2004; Durmaz 2007). However, results from feeding experiments that
have examined microalgae which are contrary in a specific nutrient are challenging to interpret because
of the confounding effects of other microalgal nutrients. Nevertheless, from examining the literature,
algal foods have been enhanced with compounded diets or emulsions, some general conclusions can be
reached (Knauer and Southgate 1999).
Algae grown to late logarithmic growth phase typically contain 30–40% protein, 10–20% lipid
and 5–15% carbohydrate (Fujii et al. 2010). In stationary phase, composition of microalgae can change
significantly for example, when nitrate is limiting, carbohydrate levels can double at the expense of protein
(Liang et al. 2009). There does not appear to be a strong correlation between the proximate composition
and nutritional value, though algal diets with high levels of carbohydrate are stated to produce the best
growth for juvenile oysters, Ostrea edulis (Ponis et al. 2006). Larval scallops, Patinopecten yessoensis
provided polyunsaturated fatty acids in adequate proportions. In contrast, high dietary protein provided
best growth for juvenile mussels, Mytilus trossulus and Pacific oysters, Crassostrea gigas (Knuckey et
al. 2002).
Algal pigments transferred to zooplankton may contribute to nutritional value (Lorenz and Cysewski
2000; Gagneux-Moreaux et al. 2007; Raja et al. 2008). Dominant pigments in the copepod, Temora sp.
are lutein and astaxanthin whereas in Artemia it was canthaxanthin (Kang and Sim 2008; Gentsch et al.
2009), these prey items were fed to halibut larvae adequate amounts of vitamin A were found in halibut
fed on copepods but not with halibut fed on Artemia. It was suggested that Artemia should routinely be
enriched with astaxanthin and lutein to improve their nutritional value. Astaxanthin and canthaxanthin
are the only pigments that can fix in the flesh of salmonids whose pinkening represents a 100 million
US$, rapidly expanding market (Raja et al. 2007c). This feed additive is produced by chemical synthesis
and available at a price of 3000 US$/kg approximately. The biological sources for astaxanthin are the
yeast, Phaffia rhodozyma (Sanderson and Jolly 1994) despite its low content (0.4%), and compared to
Haematococcus pluvialis containing 5% (Guerin et al. 2003; Kang and Sim 2008).
Some companies like Algatec-Sweden, Norbio-Norway, Biotechna-UK, Aquasearch, Cyanotech,
Maricultura, Danisco Biotechnology and Oceancolor-USA have entered the astaxanthin market. In fact,
microalgal astaxanthin has been approved in Japan and Canada as a pigment in salmonid feeds (Spolaore
et al. 2006). Feeds including 5–20% Arthrospira sp. (rich in carotene pigments), to enhance the red and
yellow patterns in carp. This clarity and color description increases their value. Another example is the
traditional French technique so-called the greening of oysters. It consists of creating a blue-green color on
the gills and labial palps of oysters using the diatom, Haslea ostrearia, it increases the product’s market
by 40% (Gagneux-Moreaux et al. 2007). For vaccine purpose Chlamydomonas sp. has been used using
the p57 antigen, the causative agent of bacterial kidney disease. This disease is caused by the intracellular
bacterium, Reinbacterium salmoninarum which affects wild and farmed salmonids. A huge concern from
an economic point of view and the symptom of disease which develops before it can be treated with
antibiotics. Fish-fed algae (4% algal dry weight of feed) fed to juvenile trout produced immunoglobulin
IgM expressed in different tissues (epithelial or blood cells).
Animal feed and aquaculture
The increased shrimp farming production mainly takes place in subtropical regions of America and
South-East Asia (72%, 3,718 hatcheries) (Alam et al. 2009). Microalgae are being in use to improve the
nutritional quality and gives coloration to the shrimps. Among these Chlorella grows in nutrient-rich
media, while Spirulina sp. requires a high pH of 9.5–11 with appropriate concentration of bicarbonate.
Similarly, Dunaliella salina grows at the high salinity of 0.5–6 M (Raja 2007b). Several algae such as
Chaetoceros sp., Isochrysis sp., Skeletonema sp., Thalassiosira sp., Tetraselmis sp. and Crypthecodinium