Table 1.
Overview of microbial production of carbohydrate biopolymers: cellulose, alginate, chitin, chitosan, and hyaluronan
ManA is mannuronic acid.
| Primary chemical structure | Metabolic precursor | Polymerizing enzyme | Natural/Industrial source | Select examples: host(s), titer, scale | Industrial application | |
|---|---|---|---|---|---|---|
| Cellulose | β-(1,4)-Linked homopolymer of d-Glc | UDP-Glc | Cellulose synthase (BcsA) | Green plants; some algae; oomycetes | Acetobacter xylinum BRC5, 15.3 g/liter, 10-liter batch (26) | Electronics (diaphragms of acoustic transducers); food (nata de coco); medicine (scaffolds for tissue engineering, wound dressing, soft tissue replacement) |
| Alginate | β-(1,4)-Linked non-repeating heteropolymer of ManA and UDP-guluronic acid | GDP-ManA | Glycosyltransferase (Alg8) | Seaweed; some bacteria | Azotobacter vinelandii, 6.6 g/liter, 1.5-liter batch reactors (99) | Feed; food (gelling agents, stabilizers); medicine (tissue scaffolds, drug delivery; research |
| Chitin | β-(1,4)-Homopolymer of GlcNAc | UDP-GlcNAc | Chitin synthase (NodC) | Fungi; crustaceans; insects; beaks of cephalopods; some fish and amphibians | GlcN: E. coli, 17 g/liter, 1-liter fed batch (43) GlcNAc: E. coli, 110 g/liter, 1-liter two-phase fed batch (43) Mixture of chitin oligosaccharides penta-N-acetyl-chitopentaose and tetra-N-acetyl-chitopentaose: E. coli, 2.5 g/liter, 2-liter fed batch (64) | Agriculture (pesticides); manufacturing (bioprinting); medicine (wound healing, drug delivery) |
| Chitosan | β-(1,4)-Linked heteropolymer of GlcNAc and GlcN | |||||
| Hyaluronan | β-(1,4)-Linked repeating heteropolymer of disaccharide units of GlcUA and GlcNAc | UDP-GlcUA + UDP-GlcNAc | Hyaluronan synthase (HasA) | Vertebrates (e.g. rooster combs); some bacteria | C. glutamicum, 21.6 g/liter, 5-liter fed batch (77) | Cosmetics; medicine (visco-supplementation, tissue repair, drug delivery) |