74
J. L. Shamshina and R. D. Rogers
crop protection, (3) as an agent to improve seed quality (as well as crop yield and
quality), and (4) as a plant growth stimulator; it also acts as amplifier of the beneficial
chitinolytic microbes [39]. Chitin is used in environmental applications as an effective biosorbent, due to presence of both hydroxyl- and acetamide-moieties (easily
modifiable into amine functionality), which demonstrate high adsorption potential
for the removal of various metal ions from water sources [40]. Chitin, in the form of
whiskers or nanofibers, can be utilized during manufacturing processes as an additive
to reinforce existing materials (packaging, fibers, etc.) [41].
Key market players, however, are approaching the market with advanced highquality medical products of higher efficacy. Unitika, Ltd. (Japan) [42] marketed a
chitin-containing non-woven dressing (Beschitin W) for the treatment of burns and
demonstrated its superior performance in speed of healing, wound adherence, exudate absorption, and scar minimization. In 1970, multiple new companies appeared
on the market. Eisai Co., Ltd. produces wound dressings from chitin, Chitipack S
®
and Chitipack P
® [43], which are used in the treatment of traumatic wounds preventing the formation of scar tissue [44]. Syvek-Patch
® produced by Marine Polymer
Technologies, Inc. is made of microfiber chitin [45], as is Excel Arrest
® dressing from
Hemostasis, LLC [46]. Numerous opportunities for chitin products can be found in
selected reviews [20–25].
4.2.3 Current Chitin Isolation Methods
Chitin isolation targets a biomass source generated by U.S.-based fisheries as a costly
waste that can be turned into valuable products. Yet, currently, chitin is isolated from
crustacean biomass via a pulping process. Pulping typically includes three steps:
(1) demineralization to remove calcium carbonate present in a shell matrix (using
acids (e.g., HCl)), (2) deproteinization to remove proteins (conducted using hydroxides (e.g., NaOH)), and (3) bleaching/discoloration (using organic solvents [47] or
oxidation agents [48]). Because pulping is conducted at relatively high temperatures (70–100 °C) and usually for a prolonged time [49, 50], the process adequately
removes both proteins and shell inorganics but generates a large amount of waste.
Manufacturing 1 kg of chitin using the pulping method requires 10 kg of biomass,
300 L of freshwater, 9 kg of HCl, 8 kg of NaOH, and 1.2 kWh of electricity. The
liquid waste generated is equal to the input freshwater volume plus the process water;
the overall amount of waste per 1 kg of chitin exceeds 500 L [26]. In addition, the
emission of CO 2 is estimated to be 0.9 kg/kg of chitin [26] Such high cost involved
in the production of chitin and the huge quantity of generated waste resulted in
the pulping process raising public and governmental concerns. As a result, there is
no chitin producing plant that uses acid/base treatment in the United States [51].
In addition, crustacean shells contain a host of potentially valuable components in
addition to chitin, including other biopolymers, such as proteins, small molecules,
such as astaxanthin that have medical value, and minerals, such as calcite that may
J. L. Shamshina and R. D. Rogers
crop protection, (3) as an agent to improve seed quality (as well as crop yield and
quality), and (4) as a plant growth stimulator; it also acts as amplifier of the beneficial
chitinolytic microbes [39]. Chitin is used in environmental applications as an effective biosorbent, due to presence of both hydroxyl- and acetamide-moieties (easily
modifiable into amine functionality), which demonstrate high adsorption potential
for the removal of various metal ions from water sources [40]. Chitin, in the form of
whiskers or nanofibers, can be utilized during manufacturing processes as an additive
to reinforce existing materials (packaging, fibers, etc.) [41].
Key market players, however, are approaching the market with advanced highquality medical products of higher efficacy. Unitika, Ltd. (Japan) [42] marketed a
chitin-containing non-woven dressing (Beschitin W) for the treatment of burns and
demonstrated its superior performance in speed of healing, wound adherence, exudate absorption, and scar minimization. In 1970, multiple new companies appeared
on the market. Eisai Co., Ltd. produces wound dressings from chitin, Chitipack S
®
and Chitipack P
® [43], which are used in the treatment of traumatic wounds preventing the formation of scar tissue [44]. Syvek-Patch
® produced by Marine Polymer
Technologies, Inc. is made of microfiber chitin [45], as is Excel Arrest
® dressing from
Hemostasis, LLC [46]. Numerous opportunities for chitin products can be found in
selected reviews [20–25].
4.2.3 Current Chitin Isolation Methods
Chitin isolation targets a biomass source generated by U.S.-based fisheries as a costly
waste that can be turned into valuable products. Yet, currently, chitin is isolated from
crustacean biomass via a pulping process. Pulping typically includes three steps:
(1) demineralization to remove calcium carbonate present in a shell matrix (using
acids (e.g., HCl)), (2) deproteinization to remove proteins (conducted using hydroxides (e.g., NaOH)), and (3) bleaching/discoloration (using organic solvents [47] or
oxidation agents [48]). Because pulping is conducted at relatively high temperatures (70–100 °C) and usually for a prolonged time [49, 50], the process adequately
removes both proteins and shell inorganics but generates a large amount of waste.
Manufacturing 1 kg of chitin using the pulping method requires 10 kg of biomass,
300 L of freshwater, 9 kg of HCl, 8 kg of NaOH, and 1.2 kWh of electricity. The
liquid waste generated is equal to the input freshwater volume plus the process water;
the overall amount of waste per 1 kg of chitin exceeds 500 L [26]. In addition, the
emission of CO 2 is estimated to be 0.9 kg/kg of chitin [26] Such high cost involved
in the production of chitin and the huge quantity of generated waste resulted in
the pulping process raising public and governmental concerns. As a result, there is
no chitin producing plant that uses acid/base treatment in the United States [51].
In addition, crustacean shells contain a host of potentially valuable components in
addition to chitin, including other biopolymers, such as proteins, small molecules,
such as astaxanthin that have medical value, and minerals, such as calcite that may