Screening And Isolation Of Tannic Acid Degrading Microorganisms And The Study About The Reduction Of Tannic Acid In Woody Forage

Tannic acid,a kind of polyhydroxy phenolic substance,is a ubiquitous antinutritional factor in plant feed since it can bind digestive enzymes,metal ions,polysaccharides and many other biological macromolecules.Tannin will affect the palatability of forage and reduce the intake of woody forage.Tannic acid can be decomposed into gallic acid and glucose under the effect of Tannase(EC3.1.1.20).In this paper,three fungi with high tannase activity were selected from typical woody forage plants,planting soils and soil of cultivation astringent persimmon.Meanwhile,the tannic acid degrading abilities of isolated fungi in woody forage were investigated by solid fermentation.The main results summarized as follows:1.Take the leaves and planting soils of Neolamarckiacadamba Roxb,Leucaenaleucoc ephala Lam.,Broussonetiapapyifera Linn,Moringaoleifera,Caesalpiniaceae Bauhinia L.and soil of cultivation astringent persimmon as the materials to screen the tannin degrading fungi.Three fungi strains that named ST-73,LT-1,HT-4 with high activity of tannase w ere isolated by plate screening and fermentation screening.The three fungus were identif ied as Aspergillus tubingensis,Aspergillus tamarii and Aspergillus oryzae respectively by ITS sequence homology alignment.2.Add the ST-73,LT-1 and HT-4 to four kinds of woody forages for solid fermentation,samples were collected on the 1,3,5,7,10,15 and 30 d.The results showed that: the content of tannin was 1.77% after 15 days fermentation with HT-4,and the degradation rate of Neolamarckiacadamba Roxb was 20.64% that was the best;After 1d ensiling,the content of tannin in Leucaenaleucocephala Lam.was 1.45% and the degradation rate was18.27%,the effect of degradation was better;After 1d ensiling,the content of tannin in Broussonetiapapyifera Linn was 0.87% and the degradation rate was 30.82%,the effect of degradation was better;respectively,the content of tannin was 0.72% after 5 days fermentation with HT-4,and the degradation rate of Caesalpiniaceae Bauhinia L.was 32.26% and it was the best.3.After determinating the nutrition content of Neolamarckiacadamba Roxb,Leucaenale ucocephala Lam.,Broussonetiapapyifera Linn and Caesalpiniaceae Bauhinia L the results showed that: the content of CP in Neolamarckiacadamba Roxb was significantly increase d and reached 17.78%,NDF and ADF were decreased(P<0.05)after 15 days fermentat ion with ST-73.The content of CP in Leucaenaleucocephala Lam.was significantly increased(P<0.05)by the fermentation with ST-73,LT-1and HT-4,and it reached 31.92%,h owever,only the LT-1 could decrease the content of NDF and ADF which were 55.80%and 36.85%.The content of CP in Broussonetiapapyifera Linn was significantly increas ed(P<0.05)by adding ST-73 and it reached 27.20%,HT-4 could significantly decrease t he content of NDF and ADF,they were 28.74% and 20.67%,respectively.HT-4 increase d the content of CP significantly(P<0.05)and decreased the content of NDF and ADF in Caesalpiniaceae Bauhinia L.after 1 day fermentation.