Influence of Culture Conditions on Poly‐3‐Hydroxybutyrate Production by a Newly Isolated Bacillus cereus Y23

YASHCHUK, OXANA; HERMIDA, ÉLIDA B

CLEAN-SOIL AIR WATER

WILEY-V C H VERLAG GMBH

Año: 2020 vol. 48

1863-0650

Polyhydroxyalkanoates (PHAs), environmental friendly polyesters, can beproduced by a wide range of microorganisms in nutrient-limiting conditions.In the present study a new bacterial strain, able to produce high quantities ofpoly-3-hydroxybutyrate (PHB), is isolated from contaminated soil. The isolateis characterized and identified as Bacillus cereus Y23, based on morphological,physiological characteristics, and 16S ribosomal RNA gene sequences. PHBproduction is evaluated using different carbon and nitrogen sources andnutritional and culture conditions are optimized. The highest PHB productionof 5.12 g L−1 was obtained in growth medium containing fructose andammonium sulfate at a C/N ratio of 30, 0.3% yeast extract, 4.5 g L−1phosphate solution, pH 7, inoculum size of 0.3%, and agitation rate of150 rpm after 48 h of incubation at 32 °C. The PHB production decrement canbe attributed to the intracellular utilization of the polymer during thestationary phase of the cellular growth and to the sporulation process. Thepresence of the main functional groups of PHB polymer is verified byFourier-transform infrared analysis. At optimum conditions, B. cereus Y23turned out to be a good candidate for industrial production of PHB since itaccumulates up to 67.9% of its dry weight.