Screening and identification of a cold-adapted cellulase-producing strains and characterization of cellulase

[Objective] In order to prepare strains for microbial fertilizer production,a cold-adapted cellulase-producing strain was screened and identified,and its characterization of cellulase was analyzed preliminarily.[Methods] CMC-Congo red staining was used to screen the cellulose-degrading strains initially under the condition of normal temperature.Low tem-perature induction was followed to screen the strain with low temperature resistance and fa-vorable cellulase activity.Then the strain mentioned above was identified by its morphologi-cal,the physiological and biochemical properties and ITS sequence analysis.Single factor test based on temperature,pH and metal ions was used to determine the influence of the cellulase activity.[Results] Strain M11 producing extracellular cellulose under 13 °C was isolated from the straw returned soil.It was identified as a Penicillium oxalicum.The results of fermentation tests showed that,when corn straw was taken as the only carbon and nitrogen sources,the ac-tivity of cellulase was maximum as 33.08 U/mL in the ninth day,under the fermentation con-ditions of 13 °C,200 r/min.The results of its cellulase characterization revealed that,the op-timum pH was 5.0 and reaction temperature was 20 °C.The relative cellulase activity still reached to 90% in the range of 5 °C?20 °C.[Conclusion] The cellulose-degrading strain Penicillium oxalicum M11 could secrete cellulase under the low temperature,and was tre-mendous potential valuable for microbial fertilizer.