- Experiment A
- Experiment B
Background Information Product Flow Improvement
- Human Practice
- TeamAbout Us Our School Our Lab Our Club Team Establishment
iGem SDSZ_China 2018
The automatic machine we designed is composed of six units. To successfully obtain industry applicable chitosan from lobster shells, the first basic part of the processing system is designed to be the purification of chitin from highly crystalized shells. We have invented five processing units that are assembled to achieve this goal. The steps are the pretreatment of raw materials, the reaction with sodium hydroxide to remove protein, rinsing, and eliminating minerals. After obtaining purified chitin, the most crucial step comes to the transformation process from chitin to chitosan through a specially designed container filled with effective enzymes that we synthesized.
Large scale of industrial production requires storage system of raw materials that ensures both the stable quality of reactants and the convenient applicability of them for further treatments.
In our design, the first unit of the machine functions to eliminate physical impurities mixed in the raw materials and as a container of the treated materials.
The storing compartment mentioned above is installed with an electric fan, heating device and a discharge gate.
When the raw materials are placed on top of a filter screen and put into the container, sodium hydroxide inside would actively react with the impurities and rinse them off the lobster shells. These impurities can be brought away and discarded through the discharge gate, leaving the roughly purified lobster shells inside the compartment above the filter screen, which can be lifted and transferred to the second reaction tank of the mechanical system.
Thus, the pretreatment and storage of raw materials can be achieved through rinsing in alkali and constant drying. The automatic design greatly eliminates the need of operators involved in the process, and thus reduces the possibility of the occurrence of safety accidents on laborers.
After crystalized lobster shells are finished with the reaction with alkali and are removed of protein, the products are put into a container that is filled with water for rinsing. A pipe derived from a diluted water tank connects to the container. The leftover protein substances sticking on the shells could be rinsed off during the process and the liquid waste can be emitted from a discharge gate at the bottom of the container. A transport device on the container takes the rinsed products to the next reaction tank.
To further purify and completely abstract chitin from crystalized lobster shells, another step of treatment is necessary for the completion of the process, which is the removal of minerals (especially calcium) inside the shells.
We decided to use hydrogen chloride to dissolve and remove the calcium inside the shells and adopted the similar design of how we treat the materials with alkali. Since there are no specific criteria in market on the use of acid in chitosan production, we used the exoskeleton of lobsters to experiment and found out that acid with the concentration of 5mol/L is the most effective dose in industry conversion.
Considering that the removal of minerals also requires the renewal of acid solution during the complete reaction, we adopted our mechanical design of the materials’ reaction with alkali.
Reaction tanks A, B, and C are adjacent to each other and are equipped with transport units. Reaction tank C is insulated with the surroundings and equipped with gas sensor.
The materials are put into reaction tank A for primary reaction with hydrogen chloride and transported to reaction tank B to react with renewed solution. After certain period of time controlled by the timer, the products are transferred into reaction tank C for detection. The final products are transferred away for rinsing after there is no more gases emitted from the reaction.
The use of low concentrated acid during the production decreases the contamination level of liquid waste to the environment and reduces safety accidents during the transformation.
The design of the detection tank ensures the completion of the reaction and saves time during the production.