The Selection Of A High Active Cellulose Decomposing Strain And The Study Of Crude Enzyme

With the advances of technology, application of fermentation microorganisms has gained more attentions in the fields of biology and agricultural science. Cellulose decomposing microorganisms, as an important part of them, were found to be very useful in the utilization of livestock and poultry manure. In this paper, totally 35 such strains were separated from manure of horse (or cattle), compost and soil, and their properties concerning enzymatic activity were extensively studied.In advantage of cellulose-congo red medium and weight losing test of the filter paper, 4 out of the above-mentioned 35 strains showed higher enzyme activities. After that, a solid state and liquid state fermentation procedure was conducted over these 4 strains and strain F10 demonstrated more desired property in comparison with strain AS3.3711, which was served as the standard. All the following experiments were carried out using this F10 as the target strain.Studies upon the growth of F10 strain indicated that cellulose-like carbon sources could induce the F10 strain to produce cellulose enzyme, while sugar-like ones acted oppositely. When nitrogen sources and trace metal ions concerned, peptone, ammonium nitrate and Fe2+ exerted stimulation effects over the process.This paper investigated the effect of temperature and pH on the growth of strain F10 and found the optimal temperature was 30℃,pH was 5.5. In the experiment of the thermal stability of the cellulose enzyme from 40℃ to 80℃, the remained enzyme activity declined quickly as temperature was over 70℃, the data showed that the temperature of the thermal denaturation was between 60℃ and 70℃. In fact, temperature and pH had great effects on the biochemical reactions, the optimal reaction conditions were as the following, temperature was 50℃, and pH was 5.0. It was found that the cellulose producing ability of F10 strain varied with the incubating time. When the strain incubated over 48 h, the ability of producing cellulose enzymes raised quickly; after 96 h, the strain hardly produces any cellulose enzymes.