Development of microbial fermentation and scale up processes for the production of value added metabolites including enzymes derives importance in industrial research. Though there are numerous studies on the production of industrial enzymes especially proteases using shake flasks, scale up studies with respect to mass transfer and hydrodynamics of fermentation in bioreactors are limited. The study deals with the production and scale up of an extracellular alkaline protease using Bacillus sp. S2 MTCC 13117 from shake flask level to 300 L fermenter. Glucose, DO, and pH profiles during scale up were studied in detail. Scale up parameters related to oxygen dynamics such as oxygen uptake rate (OUR), oxygen transfer rate (OTR), specific OUR and volumetric oxygen transfer coefficient (kLa) were evaluated. Results showed that yield coefficients with respect to biomass, product and substrate were reproduced at different levels of protease scale up in the batch mode of fermentation. Protease production was subjected to catabolite repression and it was shown to be derepressed at low specific growth rates. It was observed that the bioprocess of protease production was an aerobic one and was highly influenced by hydrodynamic conditions in the bioreactors. Use of bioreactor systems enabled effective oxygen transfer and the duration for achieving optimal protease production was reached earlier (t = 36 h in 19 L and t = 24 h in 300 L) when compared to shake flask experiments (t = 44 h). Besides, improvement in the productivity of the fermentation was substantiated by several other scale up parameters such as aeration rate, impeller tip speed, gas hold up and superficial gas velocity for effective mixing and rheological properties of the broth during fermentation in 19 and 300 L fermenters.
Background While there have been studies in Singapore on the prevalence and economic burden of osteoporotic hip fracture, there is a severe lack of reference data on bone mineral density and prevalence of osteoporosis. The purpose of this study is to establish the reference values for BMD and compare prevalence of osteoporotic conditions using other available reference values so as to better understand the status of bone health in Singaporean adults. Methods We carried out a population-based cross-sectional study using dual-energy x-ray absorptiometry (Hologic Discovery Wi) to measure the bone mineral density of Singaporean adults aged [[EQUATION]] 21 years. 314 women and 223 men were recruited from the large north-eastern residential town of Yishun. We computed T-scores (denoted by T SG ) for each individual in the study. Similar diagnoses were also done based on T-scores provided by the densitometer (T DXA ), NHANES database (T NHANES ), and China (T CHN ), and the differences in prevalence compared. We then compared the concordance between T SG and T DXA in the classification of osteoporosis. Osteoporosis was defined according to criteria by the World Health Organization (WHO). Results Peak lumbar spine BMD was 1.093±0.168g/cm 2 in women, and 1.041±0.098g/cm 2 for men. Peak whole-body BMD was 1.193±0.93g/cm 2 in women at, and 1.224±0.112g/cm 2 for men. Prevalence of osteoporosis based on lumbar spine was 9.3% in postmenopausal women, and 0.7% in men after 50 years of age. The percentage difference in prevalence range from 60.5 - 163.6%, when using reference values from T DXA , T NHANES , and T CHN . Comparing diagnosis using T DXA and T SG cut-off values, 28 versus 15 women were diagnosed as osteoporotic respectively. The kappa statistics was 0.81 for women and 0.85 for men. Conclusion Our study shows that T-scores provided by DXA manufacturer over-diagnosed osteoporosis in Singaporeans, and the prevalence of osteoporotic conditions is not accurately represented. This over-diagnosis may result in unnecessary treatment in some individuals.
Background: While there have been studies in Singapore on the prevalence and economic burden of osteoporotic hip fracture, there is a severe lack of reference data on bone mineral density and prevalence of osteoporosis. The purpose of this study is to establish the reference values for BMD and compare prevalence of osteoporotic conditions using other available reference values so as to better understand the status of bone health in Singaporean adultsMethods: We carried out a population-based cross-sectional study using dual-energy x-ray absorptiometry (Hologic Discovery Wi) to measure the bone mineral density of Singaporean adults aged ³ 21 years. 314 women and 223 men were recruited from the large north-eastern residential town of Yishun. We computed T- scores (denoted by TSG) for each individual in the study. Similar diagnoses were also done based on T-scores provided by the densitometer (TDXA), NHANES database (TNHANES), and China (TCHN), and the differences in prevalence compared. We then compared the concordance between TSG and TDXA in the classification of osteoporosis. Osteoporosis was defined according to criteria by the World Health Organization (WHO).Results: Peak lumbar spine BMD was 1.090±0.168g.cm-2 in women, and 1.041±0.098g.cm-2 for men. Peak whole body BMD was 1.193±0.93g.cm-2 in women at, and 1.224±0.112g.cm-2 for men. Prevalence of osteoporosis based on lumbar spine was 9.3% in postmenopausal women, and 0.7% in men after 50 years of age. The percentage difference in prevalence range from 60.5 - 163.6%, when using reference values from TDXA, TNHANES, and TCHN. Comparing diagnosis using TDXA and TSG cut-off values, 28 versus 15 women were diagnosed as osteoporotic respectively. The kappa statistics was 0.81 for women and 0.85 for men. Conclusion: Our study shows that T-scores provided by DXA manufacturer over-diagnosed osteoporosis in Singaporeans, and the prevalence of osteoporotic conditions is not accurately represented. This over-diagnosis may result in unnecessary treatment in some individuals.
Background: While there have been studies in Singapore on the prevalence and economic burden of osteoporotic hip fracture, there is a severe lack of reference data on bone mineral density and prevalence of osteoporosis. The purpose of this study is to establish the reference values for BMD and compare prevalence of osteoporotic conditions using other available reference values so as to better understand the status of bone health in Singaporean adults.Methods: We carried out a population-based cross-sectional study using dual-energy x-ray absorptiometry (Hologic Discovery Wi) to measure the bone mineral density of Singaporean adults aged ³ 21 years. A total of 542 participants were recruited from the large north-eastern residential town of Yishun. We computed T- scores (denoted by TSG) for each individual in the study. Similar diagnoses were also done based on T-scores provided by the densitometer (TDXA), NHANES database (TNHANES), and China (TCHN), and the differences in prevalence compared. We then compared the concordance between TSG and TDXA in the classification of osteoporosis. Osteoporosis was defined according to criteria by the World Health Organization (WHO).Results: Peak lumbar spine BMD was 1.093±0.168g/cm2 in women, and 1.041±0.098g/cm2 for men. Peak whole-body BMD was 1.193±0.93g/cm2 in women at, and 1.224±0.112g/cm2 for men. Prevalence of osteoporosis based on lumbar spine was 9.3% in postmenopausal women, and 0.7% in men after 50 years of age. The percentage difference in prevalence range from 60.5 - 163.6%, when using reference values from TDXA, TNHANES, and TCHN. Comparing diagnosis using TDXA and TSG cut-off values, 28 versus 15 women were diagnosed as osteoporotic respectively. The kappa statistics was 0.81 for women and 0.85 for men. Conclusion: Our study shows that T-scores provided by DXA manufacturer over-diagnosed osteoporosis in Singaporeans, and the prevalence of osteoporotic conditions is not accurately represented. This over-diagnosis may result in unnecessary treatment in some individuals.
Background While there have been studies in Singapore on the prevalence and economic burden of osteoporotic hip fracture, there is a severe lack of reference data on bone mineral density and prevalence of osteoporosis. The purpose of this study is to establish the reference values for BMD and compare prevalence of osteoporotic conditions using other available reference values so as to better understand the status of bone health in Singaporean adults. Methods We carried out a population-based cross-sectional study using dual-energy x-ray absorptiometry (Hologic Discovery Wi) to measure the bone mineral density of Singaporean adults aged ≥ 21 years. A total of 542 participants were recruited from the large north-eastern residential town of Yishun. We computed T- scores (denoted by TSG) for each individual in the study. Similar diagnoses were also done based on T-scores provided by the densitometer (TDXA), NHANES database (TNHANES), and China (TCHN), and the differences in prevalence compared. We then compared the concordance between TSG and TDXA in the classification of osteoporosis. Osteoporosis was defined according to criteria by the World Health Organization (WHO). Results Peak lumbar spine BMD was 1.093±0.168g/cm2 in women, and 1.041±0.098g/cm2 for men. Peak whole-body BMD was 1.193±0.93g/cm2 in women at, and 1.224±0.112g/cm2 for men. Prevalence of osteoporosis based on lumbar spine was 9.3% in postmenopausal women, and 0.7% in men after 50 years of age. The percentage difference in prevalence range from 60.5 - 163.6%, when using reference values from TDXA, TNHANES, and TCHN. Comparing diagnosis using TDXA and TSG cut-off values, 28 versus 15 women were diagnosed as osteoporotic respectively. The kappa statistics was 0.81 for women and 0.85 for men. Conclusion Our study shows that T-scores provided by DXA manufacturer over-diagnosed osteoporosis in Singaporeans, and the prevalence of osteoporotic conditions is not accurately represented. This over-diagnosis may result in unnecessary treatment in some individuals.
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