12.6 Environmental Implication
273
Energy is also consumed in transporting the fish waste from the point of collection
to the processing factory. Additional transportation is then required to get the products
to the distributor or to other manufacturers for further processing into more refined
forms or for use in other products. Renewable sources of energy could be considered
for each of these stages to minimize the environmental impact.
12.6.5 CO 2 Emission
In the extraction of collagen from fish scale, the step before the extraction with either
an acid, alkali or hydrothermal method is the removal of the calcified minerals from
the scale. This is mainly composed of calcium carbonate (CaCO 3 ) and some calcium
hydroxyapatite (Ca 10 (PO 4 ) 6 (OH) 2 ). The decalcification of scales, fins and bones is a
chemical reaction between the calcium compound and acid. For example, the reaction
between hydrochloric acid and calcium carbonate is expressed in Eq. (12.1).
CaCO 3 + 2HCl → CaCl 2 + H 2 O + CO 2
(12.1)
Given a fish scale of for example the Northern Pike fish (Esox lucius) made of
20% calcium salt (Sionkowska and Kozlowska 2014), that means for every gram of
fish scales xxx grams of CO 2 is released.
12.6.6 Salts, Acids and Alkali
Where the acid-based or alkali-based extraction is used for the extraction of acidsoluble collagen, for example, acetic acid at a concentration of 50% w/v is required
for the extraction medium in the enzyme extraction of collagen from jellyfish. More
of the same acid is used to redissolve during purification and a lower concentration
of 0.1 mol/L of acetic acid is used for the dialysis such that the acid is still required
in the enzyme extraction. In the chemical extraction, either acid or alkali can be used
for the extraction of collagen, depending on the type of collagen desired.
In the extraction of collagen from fish, skin and fins, pretreatment is usually
required to get rid of debris and non-collagenous proteins. This usually requires
treatment with 10 ml of 0.1 M sodium oxide for every gram of fish waste. To remove
fat, particularly in fish skin, alcohol is required. 10 ml of a 10% concentration of
butyl alcohol per gram of fish scales are used for this purpose. Sodium chloride is
generally used for precipitation of collagen when either low-temperature extraction
of intact collagen with acid or pepsin is being used.
Therefore, the extraction process of collagen whether enzymatic, chemical or
hydrothermal requires varying amount of additional salts, acid and alkali. Some salts
are also produced in the process of decalcification of the scales, fins and bones when
these parts are used. If these salts, acid and alkali are released to the environment they
273
Energy is also consumed in transporting the fish waste from the point of collection
to the processing factory. Additional transportation is then required to get the products
to the distributor or to other manufacturers for further processing into more refined
forms or for use in other products. Renewable sources of energy could be considered
for each of these stages to minimize the environmental impact.
12.6.5 CO 2 Emission
In the extraction of collagen from fish scale, the step before the extraction with either
an acid, alkali or hydrothermal method is the removal of the calcified minerals from
the scale. This is mainly composed of calcium carbonate (CaCO 3 ) and some calcium
hydroxyapatite (Ca 10 (PO 4 ) 6 (OH) 2 ). The decalcification of scales, fins and bones is a
chemical reaction between the calcium compound and acid. For example, the reaction
between hydrochloric acid and calcium carbonate is expressed in Eq. (12.1).
CaCO 3 + 2HCl → CaCl 2 + H 2 O + CO 2
(12.1)
Given a fish scale of for example the Northern Pike fish (Esox lucius) made of
20% calcium salt (Sionkowska and Kozlowska 2014), that means for every gram of
fish scales xxx grams of CO 2 is released.
12.6.6 Salts, Acids and Alkali
Where the acid-based or alkali-based extraction is used for the extraction of acidsoluble collagen, for example, acetic acid at a concentration of 50% w/v is required
for the extraction medium in the enzyme extraction of collagen from jellyfish. More
of the same acid is used to redissolve during purification and a lower concentration
of 0.1 mol/L of acetic acid is used for the dialysis such that the acid is still required
in the enzyme extraction. In the chemical extraction, either acid or alkali can be used
for the extraction of collagen, depending on the type of collagen desired.
In the extraction of collagen from fish, skin and fins, pretreatment is usually
required to get rid of debris and non-collagenous proteins. This usually requires
treatment with 10 ml of 0.1 M sodium oxide for every gram of fish waste. To remove
fat, particularly in fish skin, alcohol is required. 10 ml of a 10% concentration of
butyl alcohol per gram of fish scales are used for this purpose. Sodium chloride is
generally used for precipitation of collagen when either low-temperature extraction
of intact collagen with acid or pepsin is being used.
Therefore, the extraction process of collagen whether enzymatic, chemical or
hydrothermal requires varying amount of additional salts, acid and alkali. Some salts
are also produced in the process of decalcification of the scales, fins and bones when
these parts are used. If these salts, acid and alkali are released to the environment they