The Effect on Poly-β-hydroxybutyrate Production the Presence of Different Carbohydrate Sources in Bacillus ceresus and Cupriavidus necator

Polyhydroxybutyrates (PHB) are granular polyesters synthesized by many bacteria as a carbon and energy source in environments where substances such as nitrogen, oxygen, carbon, and phosphorus are limited. Polyhydroxybutyrates is biodegradable, consisting of hydrophobic long chains, and is non-toxic. It is classified as one of the basic polymers of polyhydroxyalkanoates. In this study, the Polyhydroxybutyrates production of Bacillus cereus (ATCC 10876) and Cupriavidus necator (formerly Ralstonia eutropha ATCC17699) in the presence of different minimal carbon sources was investigated under static and shaking (150 rpm) states. According to the results of the research, the highest PHB production was observed in Bacillus cereus PBS + 1% xylose medium (7.395 µg/ml) in static conditions; Cupriavidus necator exhibited the highest production of polyhydroxybutyrates under shaking conditions in PBS + 1% fructose medium (9.626 µg/ml). The lowest polyhydroxybutyrates production was observed in Cupriavidus necator in PBS + 1% maltose medium (0.027 µg/ml) under static conditions; however, under shaking conditions, it was carried out in PBS + 1% dextrose medium (0.122 µg/ml). Considering these results, it is evident that there is an increase in the production of polyhydroxybutyrates by microorganisms as the shaking speed.