Dynamic Changes Of Fungal Community During The Degradation Of Chicken Feathers Under Artificial Conditions

Keratin is a fibrous and poorly soluble structural protein.It is the third most abundant polymer in nature after cellulose and chitin.Keratin is an important component for skin,hair,feathers,horns,etc..Degraded keratin is a rich source of protein that can be used to produce feed or coating materials as well as biomedical materials.Traditional physicochemical degradation of keratin is easy to pollute the environment,and the obtained product is not ideal.Microbial degradation of keratin is a mild,efficient and energy-saving method with broad development potential and high practicability.Based on the analysis of traditional microbial plate separation culture and high-throughput sequencing technology,this study analyzed the changes of fungal community composition in different stages after adding chicken feather to the hospital greenland soils.A highly efficient keratin-degrading fungus was screened out and its optimal fermentation conditions were explored by the orthogonal experiments.Based on the results of traditional fungal plate separation and culture,it can be found that the composition of fungal community in the greenland soil of hospitals in different periods(3d,30 d,90d)was significantly different.Through the classic plate classification method,372 strains of fungi were isolated from the hospital soil added chicken feather powder.According to morphological characteristics and molecular identification,they belonged to 19 genera and 33 species.Among the fungal groups isolated from hospital green soil,155 strains of 6 genera and 12 species were isolated from the initial(YY1)samples.The fungal dominant group of the initial(YY1)samples was Penicillium,accounting for 59% of the total number of isolated fungi.In the medium-term(YY2)sample,15 genera and 15 species of 134 fungal strains were isolated,and Lecanicillium was the dominant group,accounting for 48% of the total.In the late(YY3)sample,7 genera and 11 species of 83 fungal strains were isolated,and the fungal dominant group was Microsporum,accounting for53% of the total.With the degradation of chicken feathers,the dominant group of fungi inhospital soils changed significantly during different periods.After adding keratin-rich sterile chicken feather powder to a hospital greenland soils,the composition and relative abundance of the fungal community were analyzed based on high-throughput sequencing technology.It was found that there were 6 phylas,39 orders,71 families and 128 generas in the process of degradation of keratin-rich chicken feather powder.In the different periods of the addition of chicken feather powder(in the initial 3d,mid 30 d,and late 90d),the soil fungal community in the hospital soils changed greatly.The fungal community was rich in the hospital soil(YY1)with the addition of chicken feather powder for 3d.The dominant species was Guehomyces pullulans(57.42%).After adding chicken feather powder for 30d(YY2),the relative abundance of many species in the community composition decreased.The dominant species is a uncertain genus,and its relative abundance is 77.57%.After adding chicken feather powder for 90 days(YY3),the relative abundance of some potential human pathogenic fungi increased,and the dominant species is Microsporum gypsum(55.17%),while the relative abundance of the early dominant species,the genus Guehomyces pullulans,was significantly reduced.Studies have shown that keratin-rich chicken feather powder has a significant regulatory effect on the fungal community in hospital greenland soil,especially the relative abundance and community composition of some human potential pathogenic fungi.Based on the traditional method of isolation and culture of fungi,a fungal strain 1Y2-12 efficiently degrading keratin was isolated from the hospital greenland soil in the middle of chicken powder.The morphological characteristics and molecular identification of the strain showed that the keratin strain 1Y2-12 efficiently degraded keratin belonged to the genus Lecanicillium,which is named Lecanicillium testudineum.In order to obtain the optimal fermentation conditions for the degradation of keratin in this strain,the orthogonal experiment was carried out.The results showed that the main order of the factors affecting the enzyme production of strain 1Y2-12 was N source>inorganic ion>C source,and the effect of N source on enzyme activity is the most pronounced.The optimal culture condition for the enzyme produced by strain 1Y2-12 was A2B3C1.Under this condition,the value of the enzyme produced by strain 1Y2-12 was 22.03 U/mL.