Biosynthesis and characterization of poly(3-hydroxybutyrate-co-4-hydroxybutyrate) in Alcaligenes eutrophus.
Copolyesters of 3-hydroxybutyrate (3HB) and 4-hydroxybutyrate (4HB) were produced by Alcaligenes eutrophus at 30 degrees C in nitrogen-free culture solutions containing gamma-butyrolactone alone or with fructose or butyric acid as the carbon sources. When gamma-butyrolactone was used as the sole carbon source, the 4HB fraction in copolyester increased from 9 to 21 mol% as the concentration of gamma-butyrolactone in the culture solution increased from 10 to 25 g/l. The addition of fructose to the culture solution of gamma-butyrolactone resulted in a decrease in the 4HB fraction in copolyester. The copolyesters produced from gamma-butyrolactone and fructose by A. eutrophus were shown to have random sequence distribution of 3HB and 4HB units by analysis of the 125 MHz 13C n.m.r. spectra. In contrast, a mixture of random copolyesters with two different 4HB fractions was produced by A. eutrophus when gamma-butyrolactone and butyric acid were used as the carbon sources. These results are discussed on the basis of a proposed biosynthetic pathway of P(3HB-co-4HB). The copolyester films became soft with an increase in the 4HB fraction, and the elongation to break at 23 degrees C increased from 5 to 444% as the 4HB fraction increased from 0 to 16 mol%. The P(3HB-co-10% 4HB) film was shown to be biodegradable in an activated sludge.
Doi
Y
Y
Research Laboratory of Resources Utilization, Tokyo Institute of Technology, Yokohama, Japan.
Segawa
A
A
Kunioka
M
M
D000421:Alcaligenes / Q000378:metabolism*; D001673:Biodegradation, Environmental; D005285:Fermentation; D006885:Hydroxybutyrates / Q000737:chemistry / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D011091:Polyesters / Q000737:chemistry / Q000378:metabolism*; D011108:Polymers / Q000737:chemistry / Q000378:metabolism*; D000094122:Polyhydroxybutyrates
D006885:Hydroxybutyrates; D011091:Polyesters; D011108:Polymers; C068056:poly(3-hydroxybutyrate-co-4-hydroxybutyrate); D000094122:Polyhydroxybutyrates; C003182:poly-beta-hydroxybutyrate