The Isolation,Identification and Coaggregation Characteristics of a Yeast with Starch Flocculation from Naturally Fermented Sweet Potato Sour Liquid

The PDA solid medium was used for plate coating and separation to obtain a yeast which could promote the precipitation of starch by the Lactobacillus paracasei L1 in the naturally fermented sweet potato sour liquid. It was identified by morphological observation of individuals and populations,physiological and biochemical experiments and sequencing of 26S rDNA molecules. The yeast was identified as Meyerozyma guilliermondii and designated M. guilliermondii J616. Based on the coaggregation rate,four factors which promoted the coaggregation of M. guilliermondii J616 and Lactobacillus paracasei L1 were as follows:Sterile distilled water was used as a buffer,ultrasonic dispersion treatment was performed before the incubation;the incubation condition was pH=5,the temperature was 35 ℃. And the coagulation rates were 68.8%,74.8%,70.4% and 72.7%,respectively. And yeasts in different growth stages had no significant effect on coaggregation.