Fig. 8. Studies on lignin 3D printing. (a) FDM printing process of lignin-included composite that owns the highest reported lignin contents (60 wt%) and the printed oak leaf. Reprinted with permission from ref. 93 Copyright 2018 Science Advances. (b) SLA printing of lignin-included resin that showed an improvement of the tensile strength. Reprinted with permission from ref. 86. https://pubs.acs.org/doi/abs/10.1021/acsomega.9b02455, Copyright 2019 ACS Omega. Further permissions related to the material excerpted should be directed to the ACS. (c) Modified lignin in SLA printing can be printed with the highest concentration of 15 wt%. Reprinted with permission from ref. 41. Copyright 2018 ACS Applied Materials & Interfaces. Further permissions related to the material excerpted should be directed to the ACS.