The Influence of Environmental Shock Initiation on Vegetative and Spore Production of Bacillus megaterium

Abstract

Production of B. megaterium spores as probiotic candidates is not only influenced by the nutrient composition in the culture media but also initiated by environmental factors. One of the efforts to reduce spore production costs is by utilizing wheat flour as a medium for spore growth. Large quantities of B. megaterium spore production in a short time on wheat flour media can be carried out by implementing environmental shocks. The objective of this study was to evaluate the influence of environmental shock initiation on the spore production of B. megaterium. The culture media consisted of carbon source (wheat flour) and nitrogen (ammonium chloride) at the C/N ratio of 15:3. Environmental shock conducted at 51 °C and pH of 10 in vegetative maintenance. The treatments of shock were started at the 5th, 10th, and 15th hour after inoculation, respectively. The parameters of this study were vegetative cells, spore production, sporulation efficiency and spore fraction. The highest vegetative cell was revealed in the shock initiated at 10th hour (3.5 x 108 cells. ml-1). The high density of vegetative cells did not indicate high spore production. The highest spore production in this study was found in the shock started at 15th hour (1.73 x 108 spores. ml-1) with sporulation efficiency (79%) and spore fraction was 57.28%. The target of high spore production can be achieved in the shock initiation at the 15th hour in wheat flour media.