abstract |
(57) [Problem] To provide a method for extracting a cellulase gene from a symbiotic protozoan of termites that cannot be cultured, and further using the gene to produce cellulase by a genetic engineering technique. SOLUTION: mRN is obtained from the contents of the hindgut of the termite A was extracted, a cDNA library was constructed from the mRNA, and screening was performed based on the cellulase activity. A recombinant having cellulase activity was obtained, and a novel recombinant protein having cellulase activity was obtained from a transformant transformed with a recombinant vector containing the obtained gene. This recombinant cellulase is a protozoan Sp It is derived from irotrichonympha leidyi and its optimum pH is 6. 0, optimum temperature is 70 ° C., Km value is 1.9 mg / ml, V The max was 148.2 units / mg protein. |