Effect of temperature and pH combination on vegetative cell growth of Bacillus megaterium

Abstract

B. megaterium is a potential bacterial species to be recommended as a probiotic which has been tested to have beneficial effects for fish. Vegetative cells availability is not only influenced by culture media composition but is also affected by environmental conditions such as temperature and pH. The purpose of this study was to determine the effect of temperature and pH combination on vegetative cell production and growth rate of B. megaterium. This study used a combination of temperature treatment (37, 44 and 51 °C) and pH (4, 7 and 10) to produce B. megaterium planted in wheat flour (Triticum aestivum) media. Results showed that the highest vegetative density was found at 37 °C and pH of 10 as much as 11 x 108 cells. mL−1 with a growth rate of 0.65 hour−1. In addition, the morphology of bacteria from this study presented the length and width of B. megaterium at 2.44 – 3.82 µm and 1.11 – 1.31 µm, respectively.