Optimization and the Effect of pH Adjustment for Trehalose Production by Propionibacterium acidipropionici DSM 20273

Abstract

Trehalose is a non-reducing disaccharide, which is used in the food, cosmetics and pharmaceutical industries. Microorganisms produce trehalose to protect their cells from stress conditions. The optimum conditions were determined for trehalose production by Propionibacterium acidipropionici DSM 20273 using the Taguchi method with four parameters: lactose concentration, initial pH, temperature and agitation rate. The trehalose production was optimum at a lactose concentration of 20 g.L-1, an initial of pH 7, a temperature of 30°C and an agitation rate of 100 revolutions per minute. Under these conditions, the highest yield of trehalose (595 mg.·L-1)was produced. Of the four parameters tested, the trehalose production was most affected by the temperature. To investigate the effect of pH adjustment on trehalose production, the pH was adjusted to four levels: no control of pH, control of pH at 5.5, part 1, control of pH at 7 and control of pH at 5.5, part 2. The study found that the pH adjustment increased the accumulation of trehalose. The highest volumetric production rate and yield of trehalose were found when controlling the pH at 7, during the period 114.30–192 hr (0.0113 g.L-1.hr-1 and 0.346 g.g-1, respectively). The concentration of trehalose reached 0.925 g.L-1 at the end of the fermentation. Furthermore, the efficiency of the lactose consumption was around 100 ± 10%.