Table 2. Polymers potentially targeted by Latescibacteria, their distribution and occurrence in algae, structure, degradation enzymes encoded in the Latescibacterial SAGs, potential degradation products, their transport systems encoded in the SAGs, and ultimate central catabolic pathway.

Polymer	Distribution	Degradation	Products	Transport system	Central pathway
1. Pectin
Homogalacturonan	Land plants and Charophyta green algae	Pectin methylesterase	Pectinate/ Pectate (demethylated)		EMP
		Pectin acetylesterase	Deacetylated polymer
		Pectin lyase, pectate lyase	Oligosaccharides with 4-deoxy-α-D-galact-4-enuronosyl groups at their non-reducing ends
		Exopolygalacturonate lyase	digalacturonate
		Oligogalacturonide lyase	5-dehydro-4-deoxy-D-glucuronate	ExuT symporter
			galacturonic acid
Rhamnogalacturonan I		Pectin methylesterase	Demethylated RGI
		Pectin acetylesterase	Deacetylated RGI
		Rhamnogalacturonan endolyase	Oligosaccharides with L-rhamnopyranose at the reducing end and 4-deoxy-4,5-unsaturated D-galactopyranosyl uronic acid at the non-reducing end
		Rhamnogalacturonan exolyase	disaccharide 2-O-(4-deoxy-beta-L-threo-hex-4-enopyranuronosyl)-alpha-L-rhamnopyranose
		d-4,5-unsaturated β-glucuronyl hydrolase	rhamnose	Rhamnose:proton symporter	BMC
			5-dehydro-4-deoxy-D-glucuronate	ExuT symporter	EMP
		β-galactosidase	Galactose	Galactose:sodium symporter	EMP
Alginates	Brown Algae	Poly β-D-mannuronate lyase	Oligosaccharides with 4-deoxy-α-L-erythro-hex-4-enopyranuronosyl groups at their non-reducing ends
		Oligoalginate lyase	4-deoxy-α-L-erythro-hex-4-enopyranuronose spontaneously converted to 5-dehydro-4-deoxy-D-glucuronate	ExuT symporter	EMP
2. Fucans
Homofucan	Brown Algae	Sulfatase	Unsulfated homofucans
		Fucoidan lyase-like protein (hypothetical protein)	Unsaturated, non-sulfated di- and tetrasaccharides
		α-L-fucosidase	Fucose	Fucose:proton symporter	BMC
Xylofucogalactan/ xylofucomannan		Sulfatase	Unsulfated fucans
		α-L-fucosidase	Fucose	Fucose:proton symporter	BMC
		β-glucuronidase	Glucuronic acid	ExuT symporter	EMP
Xylofucoglucuronan		Sulfatase	Unsulfated fucans
		α-L-fucosidase	Fucose	Fucose:proton symporter	BMC
3. Ulvans	Chlorophyta	Sulfatase	Unsulfated ulvans
		Heparin lyase	Unsaturated, non-sulfated di- and tetrasaccharides
		d-4,5-unsaturated β-glucuronyl hydrolase	5-dehydro-4-deoxy-D-glucuronate	ExuT symporter	EMP
			Rhamnose	Rhamnose:proton symporter	BMC
			Xylose	Xylose:proton symporter	PPP
4. Xyloglucan	Land plants, some green algae	endo-β-1,4-glucanase	A mixture of oligosaccharides
		α-1,2-fucosidase	Fucose	Fucose:proton symporter	BMC
		β-galactosidase	Galactose	Galactose:sodium symporter	EMP
		β-glucosidase	Glucose	Glucose:sodium symporter	EMP
5. Hydroxyproline-rich glycoprotein (HRGP)
Extensin	Land plants, some green algae	β-L-arabinofuranosidase	Arabinose	ABC transporter	PPP
Arabinogalactan protein (AGP)		endo-β-1,6-galactanase (?)	galactan oligosaccharides
		β-glucuronidase	Glucuronic acid	ExuT symporter	EMP
		α-Fucosidase	Fucose	Fucose:proton symporter	BMC
		α-rhamnosidase	Rhamnose	Rhamnose:proton symporter	BMC
		β-galactosidase	Galactose	Galactose:sodium symporter	EMP
6. Others
Extracellular proteins	All organisms	Non-specific endopeptidases	Oligopeptides	ABC transporter
		Dipeptidases	Dipeptides	ABC transporter
		Dipeptide peptidase, aminopeptidases, or Carboxypeptidases	Free amino acids	Symporters for Pro, Ala, Asp, Glu, Gly, cationic aaABC transporter for Pro	EMP (Asp and Glu)
Starch	Land plants, and green algae storage compounds	α-amylase	Oligosaccharides
		α-glucosidase	Glucose	Glucose:sodium symporter	EMP
Trehalose	Brown algae storage compound	Trehalase	Glucose	Glucose:sodium symporter	EMP
			Glucose-1-P
Poly-D-galactosamine	Some fungi such as Aspergillus, and Neurocrassa	Endo1,4-poly-D-galactosaminidase	Galactosamine	PTS	EMP