Screen of the Bacterial Strains for Lacti Acid Production and Optimization of its Fermentation Medium

[Objective] The basis of the lactic acid fermentation was laid.[Method The bacterial strain LP3-3,which had a higher yield of lactic acid,was obtained from 14 alkali-resistant microorganisms.The medium for the LP3-3 fermentation was optimized with single-factor experiment.[Results] The results indicated that the LP3-3 was confirmed to be Exiguobacterium aurantiacum C/N based on the preliminary identification of 16S rRNA sequencing.The optimal experiment in its fermentation medium indicated the glucose was used as the source of carbon,the yeast extract with the amount of 1% was used as nitrogen and the ratio of C/N was 5∶1.And the best component in medium was the glucose was 50.0 g/L,the yeast extract was 10.0 g/L,the peptone was 4.0 g/L,the sodium acetate(anhydrous)2.0 g/L,the ammonium citrate was 2.0 g/L,K2HPO4·H2O was 2.0 g/L,MgSO4·7H2O was 0.2 g/L,MnCl2·4H2O was 0.05 g/L,the Twain 80 was 1 ml/L,NaCl was 40 g/L and the initial pH value was 9.0.[Conclusion] The activity of LP3-3 in lactic acid fermentation was raised in the optimal medium.