Exploration of the key functional proteins from an efficient cellulolytic microbial consortium using dilution-to-extinction approach

In the present study, the cellulose binding proteins（CBPs） secreted by a putative cellulolytic microbial consortium were isolated and purified by affinity digestion. The purified CBPs were subsequently separated by sodium dodecyl sulfate–polyacrylamide gel electrophoresis（SDS-PAGE）. Using mass spectrometric analyses, eight CBPs were identified and annotated to be similar to known proteins secreted by Clostridium clariflavum DSM 19732 and Paenibacillus sp. W-61. In addition, in combination with dilution-to-extinction approach and zymogram analysis technique, CBPs 6（97 k Da） and 12（52 k Da） were confirmed to be the key functional proteins that influence cellulolytic activities. Moreover, structural domain analyses and enzymatic activity detection indicated that CBPs 6 and 12 contained glycoside hydrolase families（GH） 9 and 48 catalytic modules, which both revealed endoglucandase and xylanase activities. It was suggested that the coexistence of GH9 and GH48 catalytic domains present in these two proteins could synergistically promote the efficient degradation of cellulose.

Performance and ruminal parameters of fattening Moghani lambs fed recycled poultry bedding

This study investigated the effects of recycled poultry bedding(RPB) on performance and protozoa population, microbial enzyme activity and microbial protein synthesis(MPS) in rumen contents of fattening lambs. Thirty-six male Moghani lambs(31.4 ± 3.2 kg body weight) were fed iso-energetic and iso-nitrogenous diets containing 0, 70,140 or 210 g/kg dry matter(DM) RPB in a balanced randomized design(9 lambs per treatment). Results showed that final body weight, DM intake, average daily gain and feed conversion ratio were unchanged(P > 0.05) by RPB inclusion. Total protozoa population and subfamily of Entoniniinae and Diplodiniiae were linearly decreased by RPB(L, P < 0.05). For rumen fibrolytic enzymes including carboxymethyl-cellulase, microcrystalline-cellulase and filter paper degrading activity, the extra cellular, cellular and total(extra cellular plus cellular fraction) activity were similar(P > 0.05) by feeding the experimental diets. Inclusion of RPB in the diet linearly decreased extra cellular and total a-amylase activity(L, P < 0.05), while cellular activity was unchanged(P > 0.05). The extra cellular activity of proteases tended to increase(L, P=0.07) and their total and cellular activity increased(P > 0.05) in lambs fed RPB. Incorporation of RPB into the diet had no effect(L, P > 0.05) on urinary purine derivative excretion and MPS. In conclusion, inclusion of RPB up to 210 g/kg DM had no negative impact on performance, ruminal fibrolytic enzyme activity and MPS, while it increased rumen protease activity and decreased protozoa population in fattening Moghani lambs.