Objectives: In order to increase cellulose degradation, cellulase was expressed in this study. Literature Review: Cellulose is the most abundant organic carbon source on Earth;its enzymatic hydrolysis will be very use...Objectives: In order to increase cellulose degradation, cellulase was expressed in this study. Literature Review: Cellulose is the most abundant organic carbon source on Earth;its enzymatic hydrolysis will be very useful for bioenergy production and resource recycling. Methods: Cellobiohydrlase I (CBH I) gene was amplified from genomic DNA of Trichoderma koningii and inserted into pGAPZα A plasmid to construct the vector of pGAPZαA-CBH I. It was linearized and transformed into Pichia pastoris by electroporation. The recombinant Pichia pastoris was selected and incubated with YPD medium for cellulase secretion. Results: The result showed that CMCase and avicelase activity in the supernatant was 1.1798 U/mL and 0.1276 U/mL, the molecular weight of the expressed protein was 53 kDa determined with SDS-PAGE analyses, and the optimal temperature and pH of the expressed cellulase were 45?C - 50?C and 4.5 - 5.0, respectively. Conclusion: Cellulase gene from T. koningii has been successfully cloned and expressed in Pichia pastoris.展开更多
In order to increase nutritive values of soybean meal(SBM), 3 species of microbes were used to ferment SBM. Through a 3 x 3 orthogonal design and parameter measurements of soybean peptide and antinutritional factor co...In order to increase nutritive values of soybean meal(SBM), 3 species of microbes were used to ferment SBM. Through a 3 x 3 orthogonal design and parameter measurements of soybean peptide and antinutritional factor contents in the fermented soybean meal(FSBM), it was estimated that the best microbial proportion of Bacillus subtilis, Hansenula anomala and Lactobacillus casei was 2:1:2 for SBM fermentation(P < 0.05). The further piglet feeding experiment showed that 10% FSBM substitute for SBM had no significant effect on growth performance of suckling piglets(d 7-28)(P> 0.05). However, newlyweaned piglets(d 28-38) fed 10% FSBM and different levels of plasma protein obtained higher average daily gain(ADG) and feed conversion ratio(FCR), compared with those without FSBM but with 6% plasma protein(P < 0.05). Piglets(d 38-68) fed diets supplemented with FSBM and soybean protein concentrate(SBPC) at 3.75% and 7.5% respectively increased nutrient digestibility,fecal enzyme activity and lactic acid bacteria counts, and decreased fecal Escherichia coli counts(P < 0.05), compared with the control. These data indicated that FSBM had positive effects on nutrient digestibility and fecal microflora for piglets.展开更多
文摘Objectives: In order to increase cellulose degradation, cellulase was expressed in this study. Literature Review: Cellulose is the most abundant organic carbon source on Earth;its enzymatic hydrolysis will be very useful for bioenergy production and resource recycling. Methods: Cellobiohydrlase I (CBH I) gene was amplified from genomic DNA of Trichoderma koningii and inserted into pGAPZα A plasmid to construct the vector of pGAPZαA-CBH I. It was linearized and transformed into Pichia pastoris by electroporation. The recombinant Pichia pastoris was selected and incubated with YPD medium for cellulase secretion. Results: The result showed that CMCase and avicelase activity in the supernatant was 1.1798 U/mL and 0.1276 U/mL, the molecular weight of the expressed protein was 53 kDa determined with SDS-PAGE analyses, and the optimal temperature and pH of the expressed cellulase were 45?C - 50?C and 4.5 - 5.0, respectively. Conclusion: Cellulase gene from T. koningii has been successfully cloned and expressed in Pichia pastoris.
文摘In order to increase nutritive values of soybean meal(SBM), 3 species of microbes were used to ferment SBM. Through a 3 x 3 orthogonal design and parameter measurements of soybean peptide and antinutritional factor contents in the fermented soybean meal(FSBM), it was estimated that the best microbial proportion of Bacillus subtilis, Hansenula anomala and Lactobacillus casei was 2:1:2 for SBM fermentation(P < 0.05). The further piglet feeding experiment showed that 10% FSBM substitute for SBM had no significant effect on growth performance of suckling piglets(d 7-28)(P> 0.05). However, newlyweaned piglets(d 28-38) fed 10% FSBM and different levels of plasma protein obtained higher average daily gain(ADG) and feed conversion ratio(FCR), compared with those without FSBM but with 6% plasma protein(P < 0.05). Piglets(d 38-68) fed diets supplemented with FSBM and soybean protein concentrate(SBPC) at 3.75% and 7.5% respectively increased nutrient digestibility,fecal enzyme activity and lactic acid bacteria counts, and decreased fecal Escherichia coli counts(P < 0.05), compared with the control. These data indicated that FSBM had positive effects on nutrient digestibility and fecal microflora for piglets.
