Isolation And Identification Of Intestinal Microbial Cellulase From Termites And Its Synergistic Proteomics Analysis

As one kind of social destructive insects, termites do serious harm to the buildings, embankments、reservoirs and dams, crops, buried cables, etc, causing huge economic losses every year, it is estimated that each year1.5billion yuan of economic loss is caused by termite in China and in the United States the number is5billion dollars in1998.Therefore, it’s a long way to go to prevent and control termite.In the nature, termite is the main ingester group of cellulose, with a large number of symbiotic microorganisms that can degrade cellulose in the gut, how termite digest cellulose would be clarified through the metabolism of products, ferment by these cellulase-producing strains, this study has very important biological significance to the biocontrol of termite.In this experiment, the original strain is cellulose decomposing strain HUF-Ⅲ-620, stored in our laboratory, which is isolated from the gut of Odontotermes formosanus. The cellulase producing capacity is verified by using plate medium, which hold CMC-Na as the sole carbon source. Then, total activity of cellulase and the activity of the three components fermentation synthesised by HUF-III-620were measured, using FPA, CMC-Na, Avicel, and salicin as substrate, the results showed that the endoglucanase activity reached the maximum of1.274±0.234IU/mL at72h of fermentation, the glucosidase activity reached the maximum of1.217±0.031IU/mL at96h of fermentation; the exoglucanase activity reached the maximum of2.684±0.103IU/mL at120h of fermentation, meanwhile, the total enzyme activity reached2.849±0.269IU/mL. These results clearly shown the changes of each cellulase components activity followed by fermentation culture time of strain HUF-III-620. Moreover, by using polyacrylamide gel electrophoresis technique, every cellulase components protein, fermentation synthesised by strain HUF-III-620were isolated, then matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS) and liquid chromatograph-mass spectrometer (LC-MS/MS) were used to detect isolated proteins, determination results were contrast and compared the homology with open database, five of eight isolated proteins were identified, with five cellulase subunits:Exoglucanase1, Exoglucanase2, Endoglucanase-4, Endo-1,4-beta-xylanase and Endo-1,4-beta-xylanase A.