Isolation Of Bacillus Subtilis NH And Study On Optimizing The Fermentation Parameters Of Corn Bran

Corn bran,the by-product from machining of starch in corn,source abundant and cost cheap,is a potential feed resource.However,corn bran is difficultly digestive because of rich cellulose and poor palatability.This experiment aimed atusing the fermentation of microorganism to improve nutritive value and palatability of corn bran,reduce the content of fiber and mycotoxin of corn bran,increase the number of living bacterium in feed and enhance the value of corn bran in use.Isolation and identification of cellulase-producing strains.In order to find cellulase-producing strains with high enzyme activity.In this experiment,a cellulase-producing strain was isolated by Congo red staining and then identified by Gram stain and 16 SrDNA sequence analysis.Furthermore,the enzyme activity of this strain was determined.The results showed that this cellulase-degrading strain was Gram-positive bacteria,then homology comparison indicated that the strain was Bacillus subtilis,named Bacillus subtilis NH.And the cellulase activity of Bacillus subtilis NH was highest at 24 h,reaching 0.533 ± 0.207 U / mL.Study on optimizing the fermentation parameters of corn bran.In this experiment,fermentation was carried out using room temperature solid fermentation.And three kinds of probiotics: Bacillus coagulans,Lactobacillus crispatus,and Bacillus subtilis were mixed in equal as fermentation preparation.Corn bran,rice bran,soybean meal were mixed by 20:3:3 as fermentation substrate.The detection indexes included nutrient content,pH value,viable count,mycotoxin and sensory evaluation.To optimize the fermentation parameters,fermentation microbial inoculum was inoculated by 3%,5%,7% and 9% respectively,feed and water was mixed by 30%、40%、50% and 60% respectively,and fermentation was carried out for four periods of 1d,3d,5d and 7d respectively.The detection indexes included nutrient content,pH value,viable count,mycotoxin and sensory evaluation.The results showed that under the condition of different inoculated probiotics quantities,the inoculation amount of mixed-agents was 7% gave the best fermentation result,living bacteria reached 43.00×108/g,the NDF and ADF value were 41.5% and 14.2%separately;the ratio of material to water as independent variable,the ferment effect was best when ratio of material to water was 50%,the value of living bacteria reached 3.5×108/g was higher than others,the content of NDF and ADF respectively was 38.5% and 13.8%,significantly decrease compared with raw material;the fermentation time as independent variable,the ferment effect was the best when fermentation time was 7d,living bacteria reached 24.5×108/g,the value of NDF and ADF respectively was 38.5% and 13.8%,significantly decrease compared with raw material;So the conclusion that in the optimization of the parameters of fermenting com bran,the ferment effect was best when the inoculation amount of mixed-agents was 7%,ratio of material to water was 50% and fermentation time was 7d,the smell,color and texture of feed were significantly improved,the number of living bacteria obviously increased,the cellulose activity and CP content were significantly increased,but dry matter,the content of NDF and ADF,PH were decreased after fermentation.The above results showed that the probiotic mixed solid fermented com bran,could significantly improved the nutrition quality of corn bran,increased its utilization value by separated the production of thecellulose strain and the parameter optimization of fermenting corn bran.