Dynamic analysis of lactic acid contents and related microbes in the fermentation of Luzhou-flavour liquor

Levels of lactic acid content in the solid-state fermentation of Luzhou-flavour liquor changed regularly.The starting level of lactic acid content is 2% and increased to relative stable level as 3.5% in 2 weeks and kept till the end of fermentation.Types and amount of lactic acid related microbes, which produced or utilized lactic acid,isolated from different phases of fermentation were dynamically analyzed.The results showed that in the first week of fermentation,compared with the lactic acid production microbes (LPM) the lactic acid-utilized microbes (LUM) dominated whether on amount or activity,which made the concentration of lactic acid at a low level (2-2.5%).The amount of LUM decreased to 10~6 cfu/g,which was very similar as LPM,after one week fermentation.Changes of microbes will lead increase of lactic acid content to a higher level.It is indicated that for those strains which could produce and utilize lactic acid,their influence on solid-state fermentation is positive correlated with ability to lactic acid production.