Isolation, identification and metabolic activity of stress resistant yeast in the concentrated tobacco waste aqueous extract during the paper-making reconstituted tobacco process.

After dilution centrifugation, enrichment culture, and gradient plate screening, a series of strains that can adapt to concentrated tobacco waste water extract (TWE) and exhibit metabolic activity were isolated from concentrated TWE during the paper-making reconstituted tobacco process. Their morphological, physiological and biochemical characteristics were identified. The isolated strains were added into concentrated TWE for fermentation. The growth and metabolism characteristics and their effects on the composition of metabolites in TWE were investigated. The results showed that a yeast strain MC-9A1 resistant to high stress was isolated from concentrated TWE, which belonged to the species Zygosaccharomyces bailii. The strain MC-9A1 could grow in concentrated TWE and carried out normal metabolic activities, consuming a lot of sugar. At the same time, MC-9A1 consumed a large number of strongly polar substances and a small number of moderately polar substances in concentrated TWE, and generated a large number of weakly polar or non-polar substances. More than 310 metabolites were significantly up-regulated or down-regulated. For example, acetamide and xylitol increased significantly, while arbutin and D-galacturonic acid decreased significantly. The sensory evaluation results showed that the sensory effect was improved by fermentation of MC-9A1 in concentrated TWE, which increased aroma quality, while decreased odor and the residual. [ABSTRACT FROM AUTHOR]