Screening and obtaining a novel high activity cellulase and its producing microbe strain is the most important and essential way to improve the utilization of crop straw. In this paper, we devoted our efforts to isolating a novel microbe strain which could produce high activity cellulase. A novel strain Trichoderma virens ZY-01 was isolated from a cropland where straw is rich and decomposed, by using the soil dilution plate method with cellulose and Congo red. The strain has been licensed with a patent numbered ZL 201210295819.6. The cellulase activity in the cultivation broth could reach up to 7.4 IU/mL at a non-optimized fermentation condition with the newly isolated T. virens ZY-01. The cellulase was separated and purified from the T. virens culture broth through (NH4)2SO4 fractional precipitation, anion-exchange chromatography and gel filtration chromatography. With the separation process, the CMC specific activity increased from 0.88 IU/mg to 31.5 IU/mg with 35.8 purification fold and 47.04% yield. Furthermore, the enzymatic properties of the cellulase were investigated. The optimum temperature and pH is 50 °C and pH 5.0 and it has good thermal stability. Zn2+, Ca2+ and Mn2+ could remarkably promote the enzyme activity. Conversely, Cu2+ and Co2+ could inhibit the enzymatic activity. This work provides a new highly efficient T. virens strain for cellulase production and shows good prospects in practical application.

Water hyacinth (Eichhornia crassipes) is an invasive floating plant that has caused many environmental problems in Asia. Efficiently removing and utilizing this biomass has become an urgent issue. In this work, the composition of water hyacinth biomass (WHB) was analyzed with the Van Soest method. The combined cellulose and hemicellulose content reached 58.6%, and the lignin content was very low compared with other biomass. An efficient alkali pretreatment technology for WHB was developed, and the enzymatic hydrolysis of WHB to reducing sugars was investigated. With favorable hydrolysis conditions for the alkali-pretreated WHB, the cellulose conversion rate reached almost 100%. Structural changes resulting from WHB pretreatment and hydrolysis were analyzed by Fourier-transform infrared spectrometry and scanning electron microscopy. This work demonstrates that WHB is an alternative cellulose source for bioenergy production.

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