The production of elastase by Bacillus sp. EL31410 at various temperatures was investigated. In order to study the effect of temperature on elastase fermentation, different cultivation temperatures, ranging from 39 ℃...The production of elastase by Bacillus sp. EL31410 at various temperatures was investigated. In order to study the effect of temperature on elastase fermentation, different cultivation temperatures, ranging from 39 ℃ to 28 ℃, were evaluated in shake flask. The result indicated that 37 ℃ was best for cell growth at earlier stage; while maximum elastase activity was obtained when the cells were cultivated at 30 ℃. This result was verified by batch fermentation in 5-L bio-reactor under 37 ℃ and 30 ℃ temperature, respectively. The specific cell growth rate at 37 ℃ was higher than that at 30 ℃ during earlier stage of cultivation. The maximum value [5.5 U/(h-g DCW)] of elastase formation rate occurred at 24 h at 30 ℃ compared to 4.6 U/(h-g DCW) at 30 h at 37 ℃. Based on these results, two-stage temperature shift strategy and oscillatory temperature cultivation mode were evaluated in the next study. When compared to single temperature of 37 ℃ or 30 ℃, both two-stage temperature shift strategy and oscillatory temperature strategy improved biomass but did not yield the same result as expected for elastase production. The maximum biomass (both 8.6 g/L) was achieved at 30 h at 37 ℃, but at 42 h using two-stage temperature cultivation strategy. The highest elastase production (652 U/ml) was observed at 30 ℃ in batch process. It was concluded that cultivation at constant temperature of 30 ℃ was appropriate for elastase production by Bacillus sp. EL31410.展开更多
This paper studies on the processing technology of soybean films.Based on the statistical analysis of the traditional soybean films,two property indices were determined with Rheometer;Percent Elongation(PE) higher tha...This paper studies on the processing technology of soybean films.Based on the statistical analysis of the traditional soybean films,two property indices were determined with Rheometer;Percent Elongation(PE) higher than 5.49%,Tensile Strength(TS)higher than 23.25kg/cm^2.As the examined specimen has 19.0±0.5% moisture.An improved processing technology high yield of soybean films was obtained.The new product has the nearly same or even higher nutrient content,property and structure as the traditional ones.The new product is consistent,flexible,smooth and transparent.The method offers more promises for commercial-scale film production.展开更多
This paper focuses on the pharmacokinetics in fattening pigs as well as the change of serum resulting from the use of porcine somatotropin(PST) and its liposomes. A slow-release model was determined to be relevant to ...This paper focuses on the pharmacokinetics in fattening pigs as well as the change of serum resulting from the use of porcine somatotropin(PST) and its liposomes. A slow-release model was determined to be relevant to following an examination of all dynamic parameters. The results indicate that the slow-release effect of PST liposomes was significant, with an extended release time of over 7 d.展开更多
文摘The production of elastase by Bacillus sp. EL31410 at various temperatures was investigated. In order to study the effect of temperature on elastase fermentation, different cultivation temperatures, ranging from 39 ℃ to 28 ℃, were evaluated in shake flask. The result indicated that 37 ℃ was best for cell growth at earlier stage; while maximum elastase activity was obtained when the cells were cultivated at 30 ℃. This result was verified by batch fermentation in 5-L bio-reactor under 37 ℃ and 30 ℃ temperature, respectively. The specific cell growth rate at 37 ℃ was higher than that at 30 ℃ during earlier stage of cultivation. The maximum value [5.5 U/(h-g DCW)] of elastase formation rate occurred at 24 h at 30 ℃ compared to 4.6 U/(h-g DCW) at 30 h at 37 ℃. Based on these results, two-stage temperature shift strategy and oscillatory temperature cultivation mode were evaluated in the next study. When compared to single temperature of 37 ℃ or 30 ℃, both two-stage temperature shift strategy and oscillatory temperature strategy improved biomass but did not yield the same result as expected for elastase production. The maximum biomass (both 8.6 g/L) was achieved at 30 h at 37 ℃, but at 42 h using two-stage temperature cultivation strategy. The highest elastase production (652 U/ml) was observed at 30 ℃ in batch process. It was concluded that cultivation at constant temperature of 30 ℃ was appropriate for elastase production by Bacillus sp. EL31410.
文摘This paper studies on the processing technology of soybean films.Based on the statistical analysis of the traditional soybean films,two property indices were determined with Rheometer;Percent Elongation(PE) higher than 5.49%,Tensile Strength(TS)higher than 23.25kg/cm^2.As the examined specimen has 19.0±0.5% moisture.An improved processing technology high yield of soybean films was obtained.The new product has the nearly same or even higher nutrient content,property and structure as the traditional ones.The new product is consistent,flexible,smooth and transparent.The method offers more promises for commercial-scale film production.
文摘This paper focuses on the pharmacokinetics in fattening pigs as well as the change of serum resulting from the use of porcine somatotropin(PST) and its liposomes. A slow-release model was determined to be relevant to following an examination of all dynamic parameters. The results indicate that the slow-release effect of PST liposomes was significant, with an extended release time of over 7 d.
