Abstract:
To clarify microbial community succession and the inhibitory effect of potassium sorbate on the dominant spoilage microorganisms of tobacco casing during storage, metagenomics and molecular biological technologies were employed to systematically investigate the dynamic changes in microbial community, identify the dominant spoilage microorganism, elucidate its biological characteristics, and further evaluate the inhibitory effects of potassium sorbate against the strain. The results showed that on the 7th day of storage, the total viable count and yeast count in the tobacco casing increased by 4.7×10
3 and 2.8×10
3 CFU/mL, respectively, compared to those on the 5th day, accompanied by the emergence of sour odor, gas production and the formation of a yellow microbial film. Within 0-5 days of storage, the richness and diversity of microbial species in tobacco casing showed an upward trend but a significantly decrease on day 7, with reduced community uniformity. The microbial community structure was dominated by a limited number of species, with
Wickerhammyces gradually becoming the dominant bacterial group. The dominant spoilage microorganism was identified as
Wickerhamomyces anomalus. The optimal growth conditions for this strain were 30 ℃ with a pH value of 6.0, and the best carbon sources were sucrose, fructose, and glucose. The antibacterial results revealed that the inhibitory effect of potassium sorbate on
W. anomalus exhibited concentration dependence. At a concentration of 1.00 mg/mL, a significant delay in the growth of the strain was observed. As the concentration gradient of potassium sorbate increased, the growth of the strain gradually stagnated, and the minimum inhibitory concentration (MIC) was determined to be 8.00 mg/mL.