3D printed yeast containing hydrogel lattice can accelerate the production of alcohol and drugs.

By injecting active yeast cells into hydrogels as 3D printing ink, researchers from University of Washington produced a bioreactor using 3D printing technology This bioreactor can ferment for several days continuously and transform sugar into ethanol (ACS appl Mate Interfaces, DOI: 10.1021 / acsami 8b02719) The size of the gel lattice as the printing material can make the production of biofuels, brewing beer, synthetic drugs and other chemicals easier, faster and cheaper Embedding living cells into hydrogels is not a new idea Since 1980s, researchers have been trying to insert some types of cells (such as yeast, bacteria and algae) into hydrogels for chemical synthesis This gel is usually put into large bioreactors for batch production, which can speed up production and reduce production costs For example, to make ethanol, yeast is put into sugar, the reactor is shut down after a few days, after which the alcohol product can be separated from the mixture and the dead cells removed It is a quick way to manufacture biomaterial equipment by loading cells on gel for 3D printing However, the difficulty is to mix the cells evenly into the material structure and keep the mechanical properties and biochemical properties of the material This is because most of the previous work used biopolymers such as calcium alginate or hyaluronic acid, which began to decompose after a few days' work, so the cells would die or exudate early 3D prints the process containing the yeast hydrogel lattice (source: ACS Appl Mater Interfaces) The research team led by Alshakim Nelson and Mark A Ganter at the University of Washington, by adding two methacrylate to the Pluronic Pluronic (a commercially available three block copolymer), is used to prepare the polymer for the printing ink The polymer has many properties, making it a good 3D printing biomaterial First, it is not degradable Secondly, it has thermo sensitive properties (liquid at 5 degrees C, but becomes gelatin at 23 degrees C) Therefore, researchers can add yeast cells into cold liquids and disperse evenly, and then heat them into gel to form 3D printing The researchers used the yeast hydrogel ink to print the cubic lattice with a length of 15 mm, and irradiated the ultraviolet rays on the lattice to crosslink the hydrogel To test the fermentation performance of the lattice, the researchers immersed the lattice in a medium containing 2% glucose for two weeks and changed the fresh solution every three to four days In two weeks, the cells convert about 90% of glucose into ethanol The fermentation time can be longer, even months Hydrogels are physically limiting the growth of yeast, but they can keep them metabolically active Preliminary research shows that this is a very potential application The researchers' current idea is to print these lattices, put them into columns, and let the material flow through them Such a continuous production process has more advantages than the current production methods (industrial fermentation and chemical production often use intermittent production process), which improves production efficiency and reduces production costs Other valuable compounds, such as antibiotics and proteins, can also be produced by using other types of cells and engineered microorganisms If low-cost large-scale production of active materials can be realized and made stable enough, the technology will be very attractive for the production of high-value products such as drugs The research team is trying to evaluate the production of reactors made of 3D printing materials and traditional batch production reactors If this technology can be supported by engineering biology, it is believed that it will become a cross era revolutionary technology.