Identification and Culture Condition Optimization of a Cigar Dominant Strain with Protein Degradation Ability
[Objective]The optimal medium formula and culture conditions of the dominant strains for cigar fermentation were explored to provide the scientific basis for providing strain sources and strain scale preparation for artificial inoculation and fermentation of cigar tobacco.[Method]A dominant strain GL2 with protein degradation ability was isolated from cigar tobacco leaves.The strain was identified through 16S rDNA sequence alignment and physiological and biochemical characteristics,and the medium formula and culture conditions were optimized by single factor test and orthogonal test.[Result]The strain GL2 was identified as Bacillus safensis.The optimal medium formula included 10 g/L beef extract,35 g/L yeast extract and 0.25 g/L MgSO4.The optimal culture conditions were 2%inoculation amount(v/v),30 mL/250 mL liquid loading and 16 h of seed age.The biomass reached 1.153×1010 CFU/mL,which was 4 400 times higher than that before the optimization after the strain GL2 cultured for 24 h under the optimal medium formula and optimum culture conditions.[Conclusion]The optimized medium composition and culture conditions can promote the growth of B.safensis strain GL2,which is conducive to the large-scale preparation and application of the strain.
cigardominant strainsstrain identificationBacillus safensisoptimization of culture conditionsbiomass
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