Comparative studies on intracellular invertase from an hyperproducer (Abagboro yeast) and a commercial yeast (Saccharomyces carlsbergensis)

Abstract

The ability of yeast to secrete intracellular and extracellular forms of invertase has been demonstrated by studies, however not much research has focused on intracellular invertase. Here we report the biochemical and chromatographic properties of intracellular invertase from invertase hyperproducer obtained from Abagboro village, Ile-Ife, Nigeria and compared it with that from a brewery which had been commercially selected. Saccharomyces cerevisiae and Saccharomyces carlsbergensis were isolated from fresh palm wine obtained from Abagboro village, Ile-Ife and from green beer obtained from a local brewery, respectively. Isolates were grown on liquefied cassava-soy bean mash for 72 hours. Yeast biomass harvested was homogenized to obtain crude intracellular invertase and purified by chromatographic techniques. Physicochemical properties and kinetic parameters (Km and Vmax) of the enzymes was studied. Native and subunit molecular weights of purified invertase from an hyperproducer (Saccharomyces cerevisiae) and brewer’s yeast (Saccharomyces carlsbergensis) were 118.3 kDa and 113.38 ± 4.9 kDa; 39.12 ± 1.2 kDa and 39.34 ± 1.71 kDa, respectively. Invertase was stable for 1 hour at 50 oC, with optimum temperature of 50 oC and 55 oC for Saccharomyces cerevisiae and Saccharomyces carlsbergensis, while their activation energies were 36.225 ± 4.015 kJmol− 1 and 33.06 ± 1.810 kJmol− 1 respectively. Invertase from Saccharomyces cerevisiae and Saccharomyces carlsbergensis had optimum activity at pH 5.0 and 4.0 respectively. Both enzymes utilized similar substrates with highest affinities for sucrose. The newly identified intracellular invertase from Abagboro yeast share similar physicochemical properties with that from commercial yeast (Saccharomyces carlsbergensis).