14.4 Availability of Raw Materials
317
for application in nutrient recovery from wastewater which can then be used as animal
feed. It has also been largely explored for production of biofuel through fermentation
of its non-edible starch (Miranda et al. 2016). Another cellulose contains aquatic
plants. Water hyacinth can cover a whole hectare of water space within 6 months
growing to an estimated 125 tonnes wet weight (Istirokhatun et al. 2015).
Algae blooms have been reported in different parts of the world such as in the
southern coast of California (Smith et al. 2018). This has been accompanied by
a loss of devastating amount of fish and negative impact of the aesthetics of the
location. Algae biomass for cellulose extraction is therefore beyond abundant. It is
accumulated to devastating degree. Conversion of such waste into useful polymer
products such as cellulose is beyond its economic returns but also the gains to the
environment and all life concerned.
An estimated 100–150 billion tonnes of cellulose is produced annually by cellulose synthesizing plants, bacteria and algae (Hon 1994). Most plants contain cellulose, lignin and starch, and however, they contain these in varying compositions. The
composition of each plant will determine if the extraction of cellulose is economical,
or it might be more economical to extract other carbohydrates from them. Azolla, for
example, can accumulate 34 tonnes of cellulose in dry weight of biomass per hectare
of land annually. Although not polymers, lipids are also potential by-products from
cellulose extraction from aquatic plants. Azolla, for example, can be a source of up
to 8 tonnes of lipids per hectares annually. This is higher than other sources of lipids
of terrestrial plants such as oil palm, soy and rapeseed. Azolla has been described as
a universal biofuel crop as its chemical composition mimics that of a combination
of terrestrial and macroalgae. However, as a source of cellulose, it has moderate
cellulose composition.
Cellulose can therefore be said to be relatively abundant in the aquatic environment since it is present in fast-growing plants and aquatic algae whose biomass accumulation rate is faster than those of terrestrial plants. Actual availability of aquatic
biomass for cellulose production depends on several other factors such as demanddriven expansion of cultivation of these sources and the cost of processing compared
to the typical sources of cellulose. Future availability of abundant aquatic plants and
algae could reduce as other applications are being discovered. For example, farmers
in tropical regions had adopted water hyacinth for use as compost fertilizer (Polprasert et al. 1994). This value addition to such aquatic plant which was previously
seen as a nuisance could therefore lead to an increase in the price of the aquatic plant
as a feedstock for cellulose production.
14.5 Extraction of Aquatic Cellulose
The chemical resilience of cellulose compared to other components of the cell wall
of plants and algae serves as a basic for its extraction. The chemical-based process
for extraction involves dissolving off the other components of the cell wall in strong
acids and bases under high temperature followed by the recovery of cellulose from the
317
for application in nutrient recovery from wastewater which can then be used as animal
feed. It has also been largely explored for production of biofuel through fermentation
of its non-edible starch (Miranda et al. 2016). Another cellulose contains aquatic
plants. Water hyacinth can cover a whole hectare of water space within 6 months
growing to an estimated 125 tonnes wet weight (Istirokhatun et al. 2015).
Algae blooms have been reported in different parts of the world such as in the
southern coast of California (Smith et al. 2018). This has been accompanied by
a loss of devastating amount of fish and negative impact of the aesthetics of the
location. Algae biomass for cellulose extraction is therefore beyond abundant. It is
accumulated to devastating degree. Conversion of such waste into useful polymer
products such as cellulose is beyond its economic returns but also the gains to the
environment and all life concerned.
An estimated 100–150 billion tonnes of cellulose is produced annually by cellulose synthesizing plants, bacteria and algae (Hon 1994). Most plants contain cellulose, lignin and starch, and however, they contain these in varying compositions. The
composition of each plant will determine if the extraction of cellulose is economical,
or it might be more economical to extract other carbohydrates from them. Azolla, for
example, can accumulate 34 tonnes of cellulose in dry weight of biomass per hectare
of land annually. Although not polymers, lipids are also potential by-products from
cellulose extraction from aquatic plants. Azolla, for example, can be a source of up
to 8 tonnes of lipids per hectares annually. This is higher than other sources of lipids
of terrestrial plants such as oil palm, soy and rapeseed. Azolla has been described as
a universal biofuel crop as its chemical composition mimics that of a combination
of terrestrial and macroalgae. However, as a source of cellulose, it has moderate
cellulose composition.
Cellulose can therefore be said to be relatively abundant in the aquatic environment since it is present in fast-growing plants and aquatic algae whose biomass accumulation rate is faster than those of terrestrial plants. Actual availability of aquatic
biomass for cellulose production depends on several other factors such as demanddriven expansion of cultivation of these sources and the cost of processing compared
to the typical sources of cellulose. Future availability of abundant aquatic plants and
algae could reduce as other applications are being discovered. For example, farmers
in tropical regions had adopted water hyacinth for use as compost fertilizer (Polprasert et al. 1994). This value addition to such aquatic plant which was previously
seen as a nuisance could therefore lead to an increase in the price of the aquatic plant
as a feedstock for cellulose production.
14.5 Extraction of Aquatic Cellulose
The chemical resilience of cellulose compared to other components of the cell wall
of plants and algae serves as a basic for its extraction. The chemical-based process
for extraction involves dissolving off the other components of the cell wall in strong
acids and bases under high temperature followed by the recovery of cellulose from the