Key resources table.

Reagent type (species) or resource	Designation	Source or reference	Identifiers	Additional information
Strain, strain background (Bacillus subtilis)	NCIB3610 (abbreviated as 3610); ES3 in Shank Laboratory	Nye et al., 2017 https://doi.org/10.1128/ genomeA.00364-17	GenBank: CP020102.1	Available from the Shank lab or Bacillus Genetic Stock Center (BGSCID 3A1)
Genetic reagent (Bacillus subtilis 3610)	ES768	This study; Shank Laboratory		B. subtilis 3610 amyE::PspacC-YPet-camR; available from Shank lab
Genetic reagent (Bacillus subtilis 3610)	ES769	This study; Shank Laboratory		eps-tasA biofilm gene mutant, B. subtilis 3610 epsA-O::tet tasA::kan amyE::PspacC-YPet-camR; available from Shank lab
Gene (Bacillus subtilis)	epsA-0	GenBank	BSU_34370 through BSU_34220	Extracellular polysaccharide biosynthesis operon
Gene (Bacillus subtilis)	tasA	GenBank	BSU_24620	Major component of biofilm matrix
Gene (Bacillus subtilis)	YPet	Ethan Garner, Garner Laboratory		Yellow fluorescent protein codon-optimized for B. subtilis
Recombinant DNA reagent	pEA003	This study; Shank Laboratory		Available from Shank lab
Recombinant DNA reagent	pES037	This study; Shank Laboratory		Available from Shank lab
Biological sample (Mucor fragilis)		This study; Shank Laboratory		Isolated the strain from a tall fescue plant in the Piedmont region of North Carolina by Fletcher Halliday, University of North Carolina, 2016; available from Shank lab
Software, algorithm	Fiji/ImageJ	https://imagej.nih.gov/ij/ docs/guide/146-2.html	RRID:SCR_002285
Software, algorithm	Raman spectrum analysis software	Berry et al., 2015, http://shiny.csb. univie.ac.at:3838/scattr/
Other	Nafion	IonPower, Newcastle, DE, USA	POWDion Insoluble −40 + 60 Mesh	https://ion-power.com/product/ powdion-insoluble-4060-mesh/
Other	cryolite	Wilhelm Niemetz Minalerien, Vienna, Austria		Crystalline form from Ivigtut, Greenland