Screening And Identification Of Filamentous Fungal And Defined Fungal Liquid Starter For Glutinous Rice Wine In Submerged Fermentation

To stabilize and improve the quality of starters for standard industrial production ofglutinous rice wine production, the screening and identification of high saccharifyingRhizopus oryzae and ester-producing Endomyces fibuliger and the study on definedfungal liquid starter for glutinous rice wine in submerged fermentation were investigated.The main research contents and results are as follows:The screening and identification of high saccharifying Rhizopus oryzae. NineteenRhizopus spp. strains isolated from different solid starters were examined for their abilityto saccharify starch. Rhizopus8-3M was selected as the objective Rhizopus strainshowing the highest reducing sugar (64.4±0.6g/100g rice) and glucose production(48.1±1.4g/100g rice) after culture for3d at28?, respectively. Based onmorphological and phylogenetic analysis of26S rDNA D1/D2region and internaltranscribed spacer (ITS) sequences,8-3M was identified as Rhizopus oryzae. Theamylase activity, glucosidase activity and ethanol produced by R. oryzae8-3M weredetected. R. oryzae8-3M have potential to be applied as making defined fungal liquidstarter for glutinous rice wine considering its starch-degrading and ethanol productionability though later relatively weak.The screening and identification of ester-producing Endomyces fibuliger.Twenty-five yeast strains isolated from different solid starters were evaluated for theirability to produce esters.3-1Y was selected as the objective ester-producing yeast forobtaning the highest sensory evaluation score. Based on the morphological, cultural andphysiological tests and phylogenetic analysis of18S rDNA,26S rDNA D1/D2andinternal transcribed spacer (ITS) sequences,3-1Y was identified as Endomyces fibuliger.The ester-producing ability, amylase activity and ethanol produced by E. fibuliger3-1Ywere detected. E. fibuliger3-1Y also have potential in making defined fungal liquidstarter for glutinous rice wine as R. oryzae8-3M mentioned above.The study on defined fungal liquid starter for glutinous rice wine in submergedfermentation. Based on traditional solid starter for glutinous rice wine production, aliquid starter process was established by using pure culture from R. oryzae8-3M, E.fibuliger3-1Y and S. cerevisiae5-1Y respectively. After seven mono-factorialexperiments of defined fungal liquid starter for glutinous rice wine in submergedfermentation, results showed that significant factors affecting ethanol concentration andsensory evaluation were incubation time of R. oryzae8-3M, inoculation proportion andincubation temperature of yeast. Based on these results, RSM was employed in the later work and two ternary quadratic regression equations for ethanol concentration andsensory evaluation were built. In combination with mono-factorial experiments andresponse surface experiments, the optimum process parameters for defined fungal liquidstarter for glutinous rice wine in submerged fermentation were obtained as: incubationtime of R. oryzae8-3M,36h; inoculation proportion of yeast,7.44E. fibuliger3-1Y:2.56S. cerevisiae5-1Y; incubation temperature of yeast,27.94?. Under the optimumconditions above,8.1±0.2%(v/v) of ethanol concentration and85.3±0.7score of sensoryevaluation were achieved. The predicted values under optimization process conditionswere in good agreement with experimental datas, indicating that the optimum processparameters by RMS were reliable. The quality of glutinous rice wine was in accord withstandards of glutinous rice wine required in this paper.