Production of 3-hydroxybutyric acid trimer by Bacillus megaterium B-124

Abstract Newly isolated Bacillus megaterium B-124, which accumulated poly(3-hydroxybutyric acid) (PHB) amounting to about 20% of its dry cell weight, was found to secrete 3-hydroxybutyric acid and its trimer into the culture broth. The culture conditions were investigated and it was found that optimum conditions gave 7.6 g of the trimer per liter in 3 d of culture under the optimum conditions. The changes in the amounts of PHB, 3-hydroxybutyric acid, and its trimer during culture did not simply show that the trimer was the direct product of intracellular degradation of PHB.