Scaling up, Kinetic modeling, and Economic analysis of poly (3-hydroxybutyrate) production by Bacillus cereus isolate CCASU-P83

Abstract

Polyhydroxyalkanoates (PHA) are environmentally friendly polymers produced by many bacteria under nutrientlimited conditions. However, their commercialization is hindered by production expenses. The present study aimed at cost-effective and efficient production of poly(3-hydroxybutyrate) (PHB) by Bacillus (B.) cereus isolate CCASU-P83. Through one factor at time optimization study on shake flask, B. cereus CCASU-P83 produced about 50 % polymer per dry weight after 48 hours incubation time. For better evaluation of the fermentation process, kinetic modeling using the Logistic and Leudking-piret models was applied. A preliminary economic analysis was carried out and leads to a 30.8 % reduction in the total cost. In comparison to the findings obtained on the level of shake flask, scaling up to the bioreactor resulted in producing about 53% PHB per dry weight after only 24 hours incubation. These models concluded that B. cereus produced PHB during the growth phase. Analysis of molecular weight of the produced polymer displayed a 26900 g/mole molecular weight with a polydispersity index (PDI) of 1.1. In conclusion, B. cereus CCASU-P83 is a potential candidate for industrial production of PHB polymer using corn oil in a short incubation period which highly reduced the cost of the production process.