Optimizing conditions for production of extracellular invertase from Bacillus subtilis strain LY7/16

Invertase (EC 3.2.1.26) or β-D-fructofuranosidase, which catalyzes the hydrolysis of Oglycosyl bonds, forming an equimolar mixture of glucose and fructose from sucrose, is one of the industrially important enzymes utilized in many applications such as beverages, baking, confectionaries, nutraceuticals, and medicinal formulations. Invertase production by different varieties of yeasts, molds and fungi has been reported, but studies on invertase from bacteria are limited. In this study, Bacillus subtilis strain LY7/16, which can produce extracellular invertase with high activity (35.7 U/mg protein), was selected for optimizing culture conditions for the production of invertase. The effects of sucrose concentration, incubation time, and pH on invertase production were studied under submerged fermentation (SmF) culture conditions at 37 °C. The maximum yield of extracellular invertase (403.2 U/mg protein) was obtained at 20 % (w/v) sucrose concentration, initial pH 8.0, and an incubation time of 72 h. The optimum culture conditions showed an 11-fold increase in invertase production compared to initial experiments. These results demonstrate the potential of B. subtilis LY7/16 to produce high activity extracellular invertase, which is suitable for industrial applications.