Determination of Poly-\beta-hydroxybutyrate (PHB) Production by Some Mesophilic and Thermophilic Lactic Acid Bacteria

[摘要] Accumulated poly-\beta-hydroxybutyrate (PHB) was determined in lactic acid bacteria belonging to the genera Lactobacillus, Lactococcus and Streptococcus. Lactobacilli were grown in MRS broth and the others were grown in Elliker broth medium. Cell biomass was obtained by centrifugation. The cell walls were lysed with sodium hypochlorite. Poly-\beta-hydroxybutyrate was extracted using chloroform in a Soxhlet system. Then it was converted to crotonic acid using sulfuric acid and the amount of crotonic acid was measured spectrophotometrically. The yield of poly-\beta-hydroxybutyrate % of cell dry weight of Lactobacillus species was 0.52-25.55%. The values for Lactococcus and Streptococcus species were 0.61-14.81 and 1.20-13.69%, respectively. It was observed that one of the Streptococci and six of Lactococcus species did not produce poly-\beta-hydroxybutyrate. Generally, Lactobacillus species produced more poly-b-hydroxybutyrate than the other tested bacteria did and no significant correlation was observed between poly-\beta-hydroxybutyrate production and cell density of the cultures. Additionally, no significant difference was observed between mesophilic and thermophilic lactic acid bacteria according to PHB yield.

[学科分类] 生物科学（综合）

[关键词] Lactobacillus;Lactococcus;Streptococcus;poly-\beta-hydroxybutyrate production