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

Abstract

Polyhydroxyalkanoates (PHAs), environmental friendly polyesters, can be produced by a wide range of microorganisms in nutrient‐limiting conditions. In the present study a new bacterial strain, able to produce high quantities of poly‐3‐hydroxybutyrate (PHB), is isolated from contaminated soil. The isolate is characterized and identified as Bacillus cereus Y23, based on morphological, physiological characteristics, and 16S ribosomal RNA gene sequences. PHB production is evaluated using different carbon and nitrogen sources and nutritional and culture conditions are optimized. The highest PHB production of 5.12 g L−1 was obtained in growth medium containing fructose and ammonium sulfate at a C/N ratio of 30, 0.3% yeast extract, 4.5 g L−1 phosphate solution, pH 7, inoculum size of 0.3%, and agitation rate of 150 rpm after 48 h of incubation at 32 °C. The PHB production decrement can be attributed to the intracellular utilization of the polymer during the stationary phase of the cellular growth and to the sporulation process. The presence of the main functional groups of PHB polymer is verified by Fourier‐transform infrared analysis. At optimum conditions, B. cereus Y23 turned out to be a good candidate for industrial production of PHB since it accumulates up to 67.9% of its dry weight.

Improved fermentation strategies in a bioreactor for enhancing poly(3-hydroxybutyrate) (PHB) production by wild type Cupriavidus necator from fructose

“…and archaea (e.g. Haloarchaea ), intracellularly produce PHA granules [ 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 ], as storage of carbon and energy under limiting conditions of essential nutrients such as nitrogen or phosphate and in the presence of an excess of carbon source [ 13 , 15 , 20 ].…”

“…Recently the advantage of using fructose has been demonstrated in certain bacteria: Halomonas sp . and Bacillus sp, prefers fructose over other sources; in some cases increasing its size by using this carbon source [ 14 , 25 ].…”

Biodegradation of omethoate by Bacillus sp. YB-10: optimization of culture conditions and degradation characteristics

“…These results illustrated that inorganic nitrogen were more con-ducive than organic nitrogen for bacteria growth and omethoate degradation. Abundant organic nitrogen might restrict the use of omethoate, which correspondingly decreased the degradation rate [36]. Among the four inorganic nitrogen sources, NH 4 NO 3 has the best degradation effectivity.…”

“…This was because that the ratio of C:N is an important factor during the biodegradation of pesticides by bacteria. High concentration of NH 4 NO 3 would decrease C:N ratio, which correspondingly restricted the growth of bacteria [36,37].…”