Figure 4
From: Iridescent biofilms of Cellulophaga lytica are tunable platforms for scalable, ordered materials
Ambient growth of iridescent biofilms on porous substrates including paper facilitates handling for characterization and downstream processing. (A) C. lytica biofilms were grown in ambient conditions on a variety of porous substrates. (B) Whatman 2 filter paper placed atop nutrient agar is one of several porous substrates that allow C. lytica to form iridescent colonies. As on agar plates, living paper-associated biofilms (PABs) are green after 3 days of growth atop BB2/H2O agar (A-i) and red-shifted when salinity increases as on BB2/SS (A-ii). (C) PABs retain their iridescence after removal from agar and fixation with glutaraldehyde (B-i). Drying the fixed PABs with nitrogen causes them to lose their iridescence (B-ii). However, the structural color is restored upon rehydration (B-iii). (D) Living PABs retain their ability to respond to environmental cues. PABs from BB2/H2O agar reflect mostly green until they are moved to BB2/SS plates where reflections are shifted red (C-i and C-ii, respectively). Similarly, PABs originating on BB2/SS agar plates are red but change to green when placed on BB2/H2O (C-iv and C-v, respectively). In both cases, biofilms are able to revert back to original color when returned to the original media condition (C-iii and C-vi). Fixed biofilms do not show this dynamic behavior (C-vii and C-viii).
