Summary auto-generated
Williamson and Wilkinson developed a rapid method for isolating and estimating poly-β-hydroxybutyrate (PHB) inclusions in Bacillus species. They treated Bacillus cereus cells with alkaline sodium hypochlorite solution, which dissolved the bacterial cells while leaving lipid inclusion bodies intact. Chemical analysis revealed these isolated inclusions contained approximately 89% poly-β-hydroxybutyrate and 11% ether-soluble lipid. The PHB composition remained constant across cultures with varying inclusion contents. By measuring turbidity changes after hypochlorite treatment, the authors established a simple quantitative method for estimating PHB content in bacterial samples. Comparisons with the traditional chloroform extraction method of Lemoigne showed close agreement for cultures containing 9-40% lipid inclusions by dry weight. The new hypochlorite technique offered significant advantages: it required only small sample sizes (approximately 10 mg dry weight), was faster than existing methods, and provided accurate results across a wide range of PHB concentrations. This work confirmed that PHB polymer is the primary constituent of Bacillus lipid inclusions and provided microbiologists with a practical tool for rapid PHB quantification.
Key findings
- Alkaline sodium hypochlorite solution dissolves Bacillus cells while preserving lipid inclusions intact, enabling their isolation and analysis
- Isolated lipid inclusions consistently contain approximately 89% poly-β-hydroxybutyrate polymer and 11% ether-soluble lipid, regardless of culture conditions
- A simple turbidimetric method based on hypochlorite treatment provides rapid, accurate PHB quantification requiring only small sample sizes
- Results from the hypochlorite method agree closely with traditional chloroform extraction for cultures containing 9-40% lipid inclusions by dry weight
- Poly-β-hydroxybutyrate comprises the bulk of Bacillus lipid inclusion bodies, confirming previous hypotheses about PHB localization
This summary was generated automatically from the article PDF and is not part of the original publication. Refer to the PDF for the authoritative text.
Abstract
SUMMARY: Treatment of the cells of various Bacillus spp. with an alkaline solution of sodium hypochlorite resulted in dissolution of the cells and liberation of the intracellular lipid inclusion bodies. Analyses of the isolated and purified inclusions of Bacillus cereus grown under a variety of cultural conditions showed them to contain about 89% poly-β-hydroxybutyrate and 11% ether-soluble lipid. Parallel estimations of the poly-β-hydroxybutyrate content of intact organisms by Lemoigne's chloroform extraction method showed that all of it was present in the lipid inclusions. These observations form the basis of a simple and rapid method of estimating the poly-β-hydroxybutyrate content of Bacillus spp. It consists essentially of digesting a washed bacterial suspension with a standard alkaline hypochlorite solution under standard conditions and measuring the residual turbidity.