Screening And Effect Evaluation Of Strains For Corn Stover Fermentation

The yearly increase of corn planting area makes corn stover production also increase year by year,but due to its low price but high freight cost,only a small part of corn stover is used for producing ethanol,organic fertilizer,home cooking,heating energy and animal feed.This situation greatly affects the recycling of resources and is not in line with China’s important development strategy of protecting the environment and sustainable development.At the same time China’s livestock development is also facing the problem of lack of roughage,and in recent years China’s feed consumption from the total amount of food has been more than 40% facing the problem of human and animal competition for food.Experiment 1: Evaluation of the effect of different strains of fermented corn stover.The experiment used Aspergillus niger(T1),Xylella campestris(T2),Bacillus subtilis(T3),Bacillus licheniformis(T4),Trichoderma flavus(T5)and Saccharomyces cerevisiae(T6)to ferment corn stover,and further verified the screening of each microorganism in each fermentation time period(0,7,14 and 21 d)through fermentation sensory evaluation,chemical composition analysis and rumen in vitro fermentation on corn stover.The results showed that The results showed that: 1)T1,T4 and T5 groups were all rated as Grade 1 in sensory evaluation at 21 d.The p H value of T1,T4 and T5 groups decreased relatively faster at 21 d.The WSC content in all experimental groups reached the lowest at 21 d.The CF in each group reached the lowest value in the group at 21 d,and the CF content in T1,T5,and T4 groups was significantly lower(P<0.05)than that in the other groups.2)The 48-h gas production in each group reached the maximum value from 0 to 21 d and the theoretical maximum gas production in each group was significantly lower(P<0.05)than that before fermentation,and the 48-h gas production in each test group was higher than that in Con 1 group at 21 d.Among them,T1 and T5 groups were significantly higher than other test groups(P<0.05)The TVFA content at 21 d in Con 1,T1,T4 and T6 groups of this test was significantly higher than other fermentation days(P<0.05),and the TVFA content at 14 d in T2 group was significantly higher than other fermentation days(P<0.05),and the IVDMD,IVCPD,IVADFD,and IVADFD values in T1,T4 and T5 groups were significantly higher than other fermentation days(P<0.05).IVNDFD,IVADFD values in T1,T4 and T5 groups were significantly higher than other experimental groups(P<0.05).In summary,the fermentation quality of each fermentation treatment group was best at 21 d of fermentation,among which Aspergillus niger,Xylella campestris and Trichoderma flavus were superior.Experiment 2: Evaluation of the effect of fermentation of corn stover by compound strains.The test was conducted by using Aspergillus niger,Bacillus licheniformis and Trichoderma flavum in the composite fermentation of the superior strains obtained from the screening of test 1,and was divided into three groups: Aspergillus niger +Trichoderma flavum group(HB),Aspergillus niger + Bacillus licheniformis group(HD)and Bacillus licheniformis + Trichoderma flavum group(DB),which were further verified by fermentation sensory evaluation,chemical composition analysis and rumen in vitro fermentation.The effect of each microorganism on the fermentation of corn stover at 21 d of fermentation was further verified by sensory evaluation,chemical composition analysis and in vitro rumen fermentation.The results showed that: 1)The enzyme activities of ACX enzyme and FPA enzyme in HB group were significantly higher than those in Con 2 group(P<0.05)and higher than those in other experimental groups.the enzyme activities of C1 enzyme and β-GC enzyme in DB group were significantly higher than those in Con 2 group(P<0.05)and higher than those in other experimental groups.the contents of CF,ADF and NDF in HB and DB groups were significantly lower than those in Con 2 group(P<0.05).2)In this test,the gas production of DB group was significantly higher than that of other groups(P<0.05).TVFA of HB,HD and DB groups was significantly higher than that of Con 2 group,among which DB group was significantly higher than that of other groups(P<0.05).IVADFD of DB group was significantly higher than that of Con 2 group(P<0.05),IVDMD,IVCPD of DB,HB and HD groups were significantly higher than that of Con2 group(P<0.05).were significantly higher than those in the Con 2 group(P<0.05),and IVNDFD in the DB group was significantly higher than those in the other groups HB and HD groups(P<0.05).In summary,in the process of fermentation of dried maize straw by composite strains,the best fermentation effect was achieved by the combination of Bacillus licheniformis + Trichoderma flavus.The conclusions are as follows: The fermentation quality of each fermentation treatment group was found to be the best at 21 d of fermentation in the process of single strain fermentation of corn stover,among which Aspergillus niger,Xylella campestris and Trichoderma flavus were superior.The inoculation of 5% Bacillus licheniformis +5% Trichoderma flavum in the process of compound strain fermentation treatment of dried corn stover for 21 d improved the protein content,reduced the content of cellulose substances,and improved the digestibility of various nutrients in the rumen of dried corn stover.