Keywords Algal biomass, Application, Biofuel, Valorization, Value products
1 Introduction
Eutrophication of water bodies has been a long-term problem for which a permanent
solution has not yet been found. The factors for eutrophication are the nutrient
enrichment of water bodies and favorable growth factors like temperature, poor
circulation, and physical dimensions [1, 2]. Eutrophication disturbs the aquatic
ecosystem being superfluous in growth. The direct damage from eutrophication
are (1) reduced biodiversity, such as the loss of dominant species, (2) damage to
the water environment due to increased toxicity, and (3) changes in the physical
properties of water like increased turbidity [3]. Moreover, algal blooms affect the
ecosystem locally and indirectly the economy of the nation [4]. Economic losses of
approximately $2.2 billion for freshwater algal blooms and $100 million for coastal
algal blooms are being incurred every year in the USA [5]. The disposal cost of Ulva
species from Brittany’s coasts amounted up to US$ 10–150 per ton in 2011
[6]. Severe Microcystis and Aphanizomenon flos-aquae algal blooms in freshwater
Dianchi Lake, China pose health threats to animals and human, and their cell density
could be as high as 10
9 units/L [7]. Ten thousand wet tons of Ulva lactuca are being
produced approximately in shallow coastal estuaries in West Cork [2]. One million
tons of Ulva rigida, Valonia aegagropila, Chaetomorpha aerea, and Gracilaria
confervoides are being produced annually in Venice lagoon, Italy [8, 9]. Brown
macroalgae Fucus vesiculosus predominates the algal bloom along the German/
Danish coastline of the Baltic Sea [10]. Green tide, a rapid reproduction of toxic
marine green plankton, is often encountered in countries like Denmark, France,
Japan, China, Italy, Ireland, Australia, and Argentina [2, 8, 11–17]. Red tides have
been reported in countries like USA, Norway, Sweden, Spain, Chile, Japan, and
China due to proliferation of the toxic red algae. [18–22].
Algal bloom has now become a universal problem which is progressing in
frequency and size throughout the world. Problematic algal blooms are also found
in industrial effluents like effluent treatment plants where nitrogen and phosphorus
content and photic zones enhance their growth. Microalgal consortium of
Leptolyngbya foveolaurum and Chlorococcum infusionum was collected from
coke-oven effluent treatment plant in Durgapur, India [23]. Algal blooms not only
contaminate the water bodies but also release toxins which prove to be harmful to
humans and animals. The third largest lake in China, Taihu Lake which provides
drinking water for more than two million people, was contaminated by the foul bluegreen algal bloom during the summer of 2007. Algal bloom releases toxins in the
water bodies which find way to humans and animals through food chain or through
water pipeline systems. Microcystis aeruginosa, a cyanobacteria, produces toxins
that can damage the liver, intestines, and nervous system leading to liver failure and
diarrhea [24]. Hence it becomes imperative to find a solution to the disposal of such
nuisance causing algae since their growth is very difficult for prediction. The
methods usually adopted is skimming the algae by mechanical or manual means
130
A. Annam Renita and P. Senthil Kumar
1 Introduction
Eutrophication of water bodies has been a long-term problem for which a permanent
solution has not yet been found. The factors for eutrophication are the nutrient
enrichment of water bodies and favorable growth factors like temperature, poor
circulation, and physical dimensions [1, 2]. Eutrophication disturbs the aquatic
ecosystem being superfluous in growth. The direct damage from eutrophication
are (1) reduced biodiversity, such as the loss of dominant species, (2) damage to
the water environment due to increased toxicity, and (3) changes in the physical
properties of water like increased turbidity [3]. Moreover, algal blooms affect the
ecosystem locally and indirectly the economy of the nation [4]. Economic losses of
approximately $2.2 billion for freshwater algal blooms and $100 million for coastal
algal blooms are being incurred every year in the USA [5]. The disposal cost of Ulva
species from Brittany’s coasts amounted up to US$ 10–150 per ton in 2011
[6]. Severe Microcystis and Aphanizomenon flos-aquae algal blooms in freshwater
Dianchi Lake, China pose health threats to animals and human, and their cell density
could be as high as 10
9 units/L [7]. Ten thousand wet tons of Ulva lactuca are being
produced approximately in shallow coastal estuaries in West Cork [2]. One million
tons of Ulva rigida, Valonia aegagropila, Chaetomorpha aerea, and Gracilaria
confervoides are being produced annually in Venice lagoon, Italy [8, 9]. Brown
macroalgae Fucus vesiculosus predominates the algal bloom along the German/
Danish coastline of the Baltic Sea [10]. Green tide, a rapid reproduction of toxic
marine green plankton, is often encountered in countries like Denmark, France,
Japan, China, Italy, Ireland, Australia, and Argentina [2, 8, 11–17]. Red tides have
been reported in countries like USA, Norway, Sweden, Spain, Chile, Japan, and
China due to proliferation of the toxic red algae. [18–22].
Algal bloom has now become a universal problem which is progressing in
frequency and size throughout the world. Problematic algal blooms are also found
in industrial effluents like effluent treatment plants where nitrogen and phosphorus
content and photic zones enhance their growth. Microalgal consortium of
Leptolyngbya foveolaurum and Chlorococcum infusionum was collected from
coke-oven effluent treatment plant in Durgapur, India [23]. Algal blooms not only
contaminate the water bodies but also release toxins which prove to be harmful to
humans and animals. The third largest lake in China, Taihu Lake which provides
drinking water for more than two million people, was contaminated by the foul bluegreen algal bloom during the summer of 2007. Algal bloom releases toxins in the
water bodies which find way to humans and animals through food chain or through
water pipeline systems. Microcystis aeruginosa, a cyanobacteria, produces toxins
that can damage the liver, intestines, and nervous system leading to liver failure and
diarrhea [24]. Hence it becomes imperative to find a solution to the disposal of such
nuisance causing algae since their growth is very difficult for prediction. The
methods usually adopted is skimming the algae by mechanical or manual means
130
A. Annam Renita and P. Senthil Kumar