Research Of Synergism Of Microbes And Its Application In Traditional Guilin Rice Wine Koji

Focusing on the problem in production of traditional Guilin rice wine koji including unsteady product quantity, product pollution, black sporangium appearance; this research study characteristics of Guilin rice wine koji; isolation, identification and fermentation characteristics of microbes from traditional Guilin rice wine koji, synergism and inoculation proportion of microbes, process optimization of koji production, the conclusions are listed as follows:1. Research of characteristics of traditional Guilin rice wine koji The physical-chemical indexes, microbes and microbial colonies of traditional Guilin rice wine koji was tested. The results showed that the saccharifying power, liquefaction power, reducing sugar content of fermented rice and saccharifying power of rice fermentation of Guilin rice wine koji was 335.73 mg/g·h, 0.49 g/g·h, 24.20 g/100 g and 2.47 g/ g·h, which were lower than the two control koji samples while the ethanol yield of starch was 74.77% whice was higher than the two control koji samples; the clonies of mould, yeast and bacteria was 4.52×104 cfu/g、3.75×107 cfu/g and 5.22×104 cfu/g respectively. During the fermentation of rice wine inoculated by Guilin rice wine koji, in 0 h~16 h the sugar content of fermented rice, acid content of fermented rice and clonies of mould increased slowly; in 16 h~24 h the sugar content of fermented rice, acid content of fermented rice and clonies of mould increased rapidly, after 24 h the sugar content of fermented rice, acid content of fermented rice and clonies of mould increased slowly; in 0 h~8 h the clonies of yeast increased slowly; in 8 h~16 h the clonies of yeast increased rapidly; after 24 h the clonies of yeast increased slowly.2. Isolation, identification and fermentation characteristics of microbes from traditional Guilin rice wine koji In the research, 1 Rhizopus strain named GR1 was isolated and identified as Rhizopus oryzae based on the morphology the strain; 3 yeast strains named GY1,GY2 and GY3 were isolated and identified as Saccharomyces cerevisiae based on the morphology, physiological characteristics and 18 S r DNA sequence analysis, 3 yeast strains; 1 bateria strain named GB1 was isolated and identified as Bacillus amyloliquefaciens based on the morphology and 26 S r RNA sequence analysis.3. Research of synergism of microbes of koji process The rice wine fermentation included saccharification and alcoholic fermentation.There was high level synergism between saccharifying moulds and alcoholic fermentating yeasts.The results of synergism between bacteria and Rhizopus show that the Bacillus strain inhibited the growth of mycelium of Rhizopus. The results of synergism between Rhizopus and yeast showed that the optimum inoculation proportion of yeast is 1 × 104 cells/g, the sporangia of Rhizopus was inhibited with this inoculation proportion of yeast, high inoculation proportion of yeast inhibited sporangia and vegetative mycelia of Rhizopus, whice made the low fermentation performance of koji.4. Research of process optimization of koji The results of Rhizopus inoculation show that the optimum inoculation proportion of Rhizopus is 0.2%(w/w), the high inoculation proportion of Rhizopus led to the appearance of sporangia of Rhizopus.The results of inoculation mathod and starter material of Rhizopus showed condition of Rhizopus inoculation is inoculating by Rhizopus bran starter, using cooked rice powder as the material of Rhizopus starter. The results of research of process optimization showed the optimal technological condition of koji was processing with 40%(w/w) water added, cultivating in 30 ℃ and using raw rice powder as material.The results of proving test show that reducing sugar content of fermented rice noculated with the koji processed in the optimal technological condition is 27.61 g/100 g, the saccharification performance of the koji processed in the optimal technological condition is better than the traditional Guilin rice wine koji; saccharifying power, acid content and alcohol content of rice fermentation was 2.42 g/g·h、2.06 g/kg and 2.81%vol respectively.