Isolation and Identification of Yeasts from Tomato Natural Fermentation Broth and Its Characteristics Analysis

To study the yeast and its characteristics in tomato fermentation broth,the gradient dilution method was used to isolate and purify the yeast in the tomato fermentation broth for 30 days of natural fermentation. The strain was identified by colony morphology,microscopic characteristics and 26S rDNA sequence analysis,the growth characteristics and tolerance of the identified strain were analyzed. The results showed that three strains of yeast TY-1,TY-2 and TY-3 from tomato fermentation broth were all Pichia kudriavzevii. Among which TY-1 and TY-2 were identified as the same strain as P. kudriavzevii strain SLDY-035,their homology was 99%.The homology between TY-3 and P. kudriavzevii small subunit ribosomal was 100%. The optimum growth temperature and pH of TY-1 and TY-3 was 29 ℃ and 5.5,respectively,they were tolerant to 10%~30% glucose and 6%~9% alcohol. The yeast strains isolated from tomato fermentation broth had good growth performance,which could lay a foundation for the development of fruit and vegetable fermentation agents.