The Effect Of Enzymes Production By Mixed Culture Two Filamentous Fungi In Solid State Fermentation-Effect On Mixed Culture Of Filamentous Fungi And Aspergillus Oryzae Su-16

It is a common phenomenon that fermented with more than single microorganism, whichis also the flavor foundation of many fermentative foods. In order to investigate therelationship and influence between two kinds of filamentous fungi mixed cultured in solidmatrix, Aspergillus oryzae Su-16and six other filamentous fungi, which were separated frombrewing raw wheat koji, mixed cultured and inoculation alone in wheat bran mediumrespectively for solid-state fermentation. Four kinds of enzymes activity, α-amylase,glucoamylase, neutral protease, cellulose, and three other characters of bran koji, proteincontent, total acids and pH were analyzed. Differences were found between mixed culturedbran koji and the sum of two bran koji fermented by single fungi, by using correlationcoefficient analysis with SPSS16.0software. Combined with the SDS-PAGE analysis of brankoji and the criss-cross culture of two fungi in plate, all results show that the influencebetween A. oryzae Su-16and Aspergillus niger AN-13is maximum relatively among the sixcombinations. Furthermore, A. oryzae Su-16mainly disturb physiological metabolism ratherthan growth and differentiation of A. niger AN-13. In another combination, A. oryzae Su-16cultured with Rhizomucor pusillus RP-09, the latter significantly inhibit myceliumdifferentiation and sporulation of A. oryzae Su-16.Soluble proteins in bran koji under mixed culure and single culture were compared andanalyzed by two-dimensional gel electrophoresis(2-DE) and identified by mass spectrometry.In the combination of A. oryzae Su-16and Rhizomucor pusillus RP-09, the expression ofalkaline proteinase and arabia xylanase from A. oryzae dropped under the mixed culture,while beta-1,4-xylosidase, taka-amylase A precursor, unnamed protein product with chitinbinding domain disappeared. Rhizomucor pusillus RP-09had seven protein spots, which didnot express in the mixed culture; there was a new protein spot in the mixed culture. In thecombination of A. oryzae Su-16and A. niger AN-13, the expression of alkaline proteinasefrom A. oryzae dropped, there were five new protein spots, which first appeared in the thecultivation of the A. oryzae Su-16, and other three protein spots rised; there were thirteenprotein spots which belonged to A. niger AN-13, but those didn’t express in the mixed culture.The results of the differential proteins spots’analysis illustrated that the interaction effect onthe enzyme production exsited in the mixed culture of the A. oryzae Su-16with Rhizomucorpusillus RP-09and with A. niger AN-13.To further clarify the mixed culture system which components played a role, the dialysisculture techniques was used to study the system which consisted of A. oryzae Su-16andRhizomucor pusillus RP-09, A. oryzae Su-16and Aspergillus niger AN-13. The liquid staticdialysis culture experiment was done to study the impact strength of fungal mycelia andextracellular proteins, small molecule metabolites in mixed culture. Aspergillus niger AN-13 and Rhizomucor pusillus RP-09impacted little on A. oryzae Su-16’s protein secretion andenzyme activity by the molecular weight of less than200KDa substance; Rhizomucorpusillus RP-09produced the molecular weight of less than10KDa substance which had acertain role in promoting the growth of A. oryzae Su-16; A. niger AN-13produced themolecular weight between10KDa and200KDa substance which had a certain role ininhibiting the growth of A. oryzae Su-16; A. niger AN-13produced the molecular weight ofless than10KDa substance which had a certain role in promoting the growth of A. oryzaeSu-16.