Construction Of High Efficient Cotton Stalk Degradation Of Microbial System And Its Characteristics

Returning cotton stalks to field is an effective measurement to resolve the problem of soil fertility decline under great agricultural environment. At the same time, cotton stalk can be effectively used, so that incineration waste and environmental pollution can be avoided. However, the degradation rate of cotton stalk is very slow under natural condition due to the special structure of cotton stalk. It is necessary to solve the problem of fast degradation of cotton stalk. The aim of this research is to construct a microbial system that can decompose cotton stalk with high efficiency, according to the principle of synergism between different microorganisms.Firstly, four microbial systems of cotton stalk degradation were screened and domesticated from seven kinds of soil samples with four kinds of culture medium. After a series of passage and domestication, four microbial systems with stable effect of cotton stalk degradation were constructed. They were microbial systems of W, Z, C and F. The cotton stalk degradation rate in 7 days of the four microbial systems were stable at about 27.74%, 29.17%, 33.81% and 35.49%, respectively. It is discovered that the four microbial systems were all composed of bacteria through separation and purification , and microscopic observation.Further, the four microbial systems were recomposed to construct a microbial system that could decompose cotton stalk with high efficiency, according to the principle of synergism between different microorganisms. The microbial system resulted from combined inoculation of the Z microbial system, C microbial system and F microbial system had the highest degradation efficiency. the cotton stalk degradation rate in 7 days of the microbial system was 38.34%. But the degradation efficiency declined in the process of subculture of this microbial system, Therefore, we construct the high efficienct cotton stalk degradation of microbial system, the ZFC microbial system, with the method of conserving and subculturing Z microbial system, C microbial system and F microbial system respectively, and mixed inoculating when used.Liquid state fermentation of the ZFC microbial system was conducted under different culture conditions. The pH, weight loss rate of cotton stalks, microbial growth and cellulase activity in the process of fermentation were studied and compared. The result indicated that the condition of static culture at 28℃was more fit for growth, enzyme production and degradation of cotton stalk of the ZFC microbial system. The degradation rate of cellulose, hemicellulose and lignin in cotton stalk of the ZFC microbial system were respectively 21.0%,65.1% and 46.3% in 13 d under the condition of static culture at 28℃.