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

Abstract:

[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 temperature induction was followed to screen the strain with low temperature resistance and favorable cellulase activity. Then the strain mentioned above was identified by its morphological, 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 activity of cellulase was maximum as 33.08 U/mL in the ninth day, under the fermentation conditions of 13 °C, 200 r/min. The results of its cellulase characterization revealed that, the optimum 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 tremendous potential valuable for microbial fertilizer.