Biosynthesis of poly-3-hydroxybutyrate by Sphaerotilus natans

• Published in: Applied microbiology and biotechnology Vol. 43; no. 1; pp. 31 - 34
• Main Authors: TAKEDA, M, MATSUOKA, H, HAMANA, H, HIKUMA, M
• Format: Journal Article
• Language: English
• Published: Berlin Springer 01-04-1995
• Subjects: Biological and medical sciences; Biotechnology; Fundamental and applied biological sciences. Psychology; Methods. Procedures. Technologies; Microbial engineering. Fermentation and microbial culture technology; Sphaerotilus natans; Temperature; Batchwise; Sphaerotilus natans; Bacteria; Butyrate(hydroxy)polymer; Environmental factor; Biosynthesis; Mutation; Fermentation; Optimization
• ISSN: 0175-7598; 1432-0614
• DOI: 10.1007/bf00170618

A sheathed bacterium Sphaerotilus natans could not survive at 4 degree C for 2 months, and mutants that exhibited different colony phenotypes were obtained only by repeating the short period of storage at 4 degree C. The ability of these mutants and the parent strain to produce poly-3-hydroxybutyrate (PHB) was compared in batch cultures. The parent strain accumulated 30% (w/w) PHB, while one of the mutants defective in sheath formation, designated as T2, accumulated over 50% PHB. Because T2 did not require strict air or nitrogen limitation for polymer accumulation, its production was growth-associated, allowing one-stage fermentation. In a pH-controlled fermentation using a jar fermentor, 10 g/l glucose was converted into 2.0 g/l PHB in 24 h. (Eikelboom 1975), and great attention has been paid to controlling its increase. In the course of extensive study of the properties of S. natans, it was found to be able to accumulate PHB up to 40% (w/w) of the dry weight of its biomass under certain cultivation conditions (van Veen et al. 1978). However, no detailed studies focusing on PHB production using S. natans have been reported yet. Thus, the aim of the present study was to investigate and optimize the PHB production abilities of S. natans and the mutants that were derived from it by repeated low-temperature treatment.