Low Acyl Gellan Gum as a Gelling Agent in Medium of Saccharomyces Yeasts

Abstract Commercial agar used in microbiological culture has a disadvantage of impurity and opacity. This work aimed to provide an alternative gelling agent to agar and the function of low acyl gellan gum in microbiological culture media was studied. The results showed the texture and water activity of GYGs (glucose-YNB medium containing low acyl gellan gum at different concentrations of 0.3%, 0.6%, 0.9%, 1.2%, 1.5%) were suitable for cultivation of Saccharomyces yeasts. The gelling temperature of GYGs was enhanced with the increased concentration of low acyl gellan gum, while clarity of medium and colony diameter decreased. Scanning electron microscope showed that GYG09 (glucose-YNB medium containing 0.9% low acyl gellan gum) possessed homogeneous porous structures, which was superior to GYA20 with respect to higher clarity and lower dosage of gelling agent when surface plating method was used; however, GYG09 was not suitable for pour plating method.