Production of rubusoside from stevioside by using a thermostable lactase from Thermus thermophilus and solubility enhancement of liquiritin and teniposide.Solubility is an important factor for achieving the desired plasma level of drug for pharmacological response.  Recombinant lactase from Thermus thermophiles which was expressed in Escherichia coli converted stevioside to rubusoside as a main product. 
THERM