Investigation into Screening,Identifying and Solid-State Fermentation of Cellulolytic Strains

Twelve strains were isolated from putrid straw,wood,soil and cattle feces etc. They can grow in a solid medium with(sodium carboxymethyl cellulose) CMC-Na as an only carbon source.One strain of fungi,preliminarily identified as Neurospora sp.,with a strong ability to decompose cellulose was screened from the 12 strains by a series of experiments.The experiment of single factor optimization about the solid-state fermentation of this strain was carried out.The research results shows that to the strain,the optimal carbon and nitrogen sources are that the mass ratio of straw to bran is(9 to 1,) and NH4NO3 0.5%;and that the optimal conditions for culture are that the inoculum’s size is 1 mL,the ratio of solid to liquid 1 to 3,culture temperature around 30 ℃ and cultivating time 96 h under the condition of a natural pH value.The carboxyl methyl cellulase activity and the filter paper activity of Neurospora sp.are 3551.1 and 386.7 μmol/(g·h) respectively under these optimal zymotic conditions.