The Experts below are selected from a list of 51405 Experts worldwide ranked by ideXlab platform
Jianzhong Huang - One of the best experts on this subject based on the ideXlab platform.
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two stage Oxygen Supply strategy for enhancing fed batch production of pyrroloquinoline quinone in hyphomicrobium denitrificans fjnu 6
Applied Microbiology and Biotechnology, 2020Co-Authors: Mengsu Liu, Xinwei Yang, Yang Ren, Huaping Xia, Jianzhong HuangAbstract:Oxygen is a vital parameter for pyrroloquinoline quinone (PQQ) biosynthesis. In this study, the effects of Oxygen Supply on the biosynthesis of PQQ were first investigated systematically with Hyphomicrobium denitrificans FJNU-6. Following a kinetic analysis of the specific cell growth rate (μx) and specific PQQ formation rate (μp) in 5 L benchtop fermentation systems at various Oxygen Supply levels ranging from 0 to 60%, a novel, two-stage Oxygen Supply strategy was developed for enhancing PQQ production and productivity. Moreover, the transcription of genes involved in methanol oxidation and PQQ biosynthesis was analyzed throughout the process to outline the effect of Oxygen Supply on cell metabolism. Furthermore, with constant feeding of methanol at 0–1 g/L after the initial methanol was consumed completely, the PQQ concentration and productivity reached 1070 mg/L and 7.64 mg/L/h, respectively, after 140 h in a 5-L fermenter. The two-stage Oxygen Supply strategy developed in this study provides an effective and economical strategy for the industrial production of PQQ. Key Points • A novel, two-stage Oxygen Supply strategy was developed for enhancing PQQ production and productivity. •The transcription of genes involved in methanol oxidation and PQQ biosynthesis was regulated by changes in Oxygen Supply. • This study offers an effective and economical strategy for industrial or large-scale production of PQQ.
Zhongping Shi - One of the best experts on this subject based on the ideXlab platform.
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a two stage Oxygen Supply strategy for enhanced l arginine production by corynebacterium crenatum based on metabolic fluxes analysis
Biochemical Engineering Journal, 2009Co-Authors: Wenfang Dou, Xiaomei Zhang, Zhiming Rao, Zhongping ShiAbstract:Abstract In this study, the metabolic flux distribution analysis of a new l -arginine (Arg) overproducing strain, Corynebacterium crenatum, was carried out under various Oxygen Supply conditions in order to explore the optimized Oxygen Supply profile. The metabolic flux analysis indicated that a relatively higher l -arginine production could be obtained under high Oxygen Supply (HOS) condition overall. However, during the late fermentation phases, a much more stable l -arginine production could be rather achieved under medium Oxygen Supply (MOS) condition. As a result, a two-stage Oxygen Supply strategy, which maintained HOS condition during early fermentation phase, and then step-wisely reduced agitation to keep a stable, smooth and moderate dissolve Oxygen levels (DO) changing profile throughout the production phases, was proposed. With the proposed control strategy, the final l -arginine concentration of the batch fermentation was largely increased and reached to a high level of 36.6 g L−1, which was 16% and 51% higher than those obtained under the HOS and MOS conditions. The two-stage Oxygen Supply strategy could also accelerate glucose consumption rate and thus shorten fermentation time under the same batch initial fermentation condition. The relevant metabolic flux analysis verified the effectiveness of the proposed control strategy.
Mengsu Liu - One of the best experts on this subject based on the ideXlab platform.
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two stage Oxygen Supply strategy for enhancing fed batch production of pyrroloquinoline quinone in hyphomicrobium denitrificans fjnu 6
Applied Microbiology and Biotechnology, 2020Co-Authors: Mengsu Liu, Xinwei Yang, Yang Ren, Huaping Xia, Jianzhong HuangAbstract:Oxygen is a vital parameter for pyrroloquinoline quinone (PQQ) biosynthesis. In this study, the effects of Oxygen Supply on the biosynthesis of PQQ were first investigated systematically with Hyphomicrobium denitrificans FJNU-6. Following a kinetic analysis of the specific cell growth rate (μx) and specific PQQ formation rate (μp) in 5 L benchtop fermentation systems at various Oxygen Supply levels ranging from 0 to 60%, a novel, two-stage Oxygen Supply strategy was developed for enhancing PQQ production and productivity. Moreover, the transcription of genes involved in methanol oxidation and PQQ biosynthesis was analyzed throughout the process to outline the effect of Oxygen Supply on cell metabolism. Furthermore, with constant feeding of methanol at 0–1 g/L after the initial methanol was consumed completely, the PQQ concentration and productivity reached 1070 mg/L and 7.64 mg/L/h, respectively, after 140 h in a 5-L fermenter. The two-stage Oxygen Supply strategy developed in this study provides an effective and economical strategy for the industrial production of PQQ. Key Points • A novel, two-stage Oxygen Supply strategy was developed for enhancing PQQ production and productivity. •The transcription of genes involved in methanol oxidation and PQQ biosynthesis was regulated by changes in Oxygen Supply. • This study offers an effective and economical strategy for industrial or large-scale production of PQQ.
James Duffin - One of the best experts on this subject based on the ideXlab platform.
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Fail‐safe aspects of Oxygen Supply
The Journal of Physiology, 2020Co-Authors: James DuffinAbstract:KEY POINTS A fall in Oxygen Supply releases a remedial response that is otherwise prevented when the Oxygen Supply is sufficient; for example, the remedial function of HIF-1α is released when Oxygen levels fall. CONCEPT the physiological responses initiated when Oxygen Supply is compromised operate in a fail-safe manner. This concept is applied to two cases: the control of cerebral blood flow, and the detection of hypoxia by the carotid body. The fail-safe Oxygen Supply concept was tested with simple computer simulations to demonstrate its function and verify the ability to reproduce measured data. The computer model reproduced published observations, suggesting that the fail-safe concept can be considered as a principle that provides novel insight into the physiology of Oxygen Supply in these cases. ABSTRACT An engineered fail-safe system automatically prevents or mitigates the consequences of a system failure. This operational concept can be applied both to the delivery of Oxygen to the brain during hypoxia and anaemia, and to the carotid body response to hypoxia and hypercapnia. I aimed to develop simple mathematical models of these fail-safe processes and examine their ability to replicate experimental observations. The intent is to demonstrate the validity of applying the fail-safe concept, not to reveal the details of the physiology involved. The model calculations are based on a single compartment of the relevant tissue in each case that is challenged with a decrease in Oxygen Supply. The model equation parameters were adjusted to reproduce experimental observations. The fail-safe model of cerebral blood flow control yielded results similar in form to published experimental observations of the cerebral blood flow responses to hypoxia and anaemia. The fail-safe model of carotid body glomus cell control of intracellular hydrogen ion concentration also yielded results similar in form to observations of carotid sinus nerve responses to hypoxia and hypercapnia. The ability of these simple models to simulate experimental observations demonstrates the applicability of the fail-safe concept to Oxygen delivery. I suggest that a fail-safe view of Oxygen delivery provides novel physiological insight.
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fail safe aspects of Oxygen Supply
The Journal of Physiology, 2020Co-Authors: James DuffinAbstract:KEY POINTS A fall in Oxygen Supply releases a remedial response that is otherwise prevented when the Oxygen Supply is sufficient; for example, the remedial function of HIF-1α is released when Oxygen levels fall. CONCEPT the physiological responses initiated when Oxygen Supply is compromised operate in a fail-safe manner. This concept is applied to two cases: the control of cerebral blood flow, and the detection of hypoxia by the carotid body. The fail-safe Oxygen Supply concept was tested with simple computer simulations to demonstrate its function and verify the ability to reproduce measured data. The computer model reproduced published observations, suggesting that the fail-safe concept can be considered as a principle that provides novel insight into the physiology of Oxygen Supply in these cases. ABSTRACT An engineered fail-safe system automatically prevents or mitigates the consequences of a system failure. This operational concept can be applied both to the delivery of Oxygen to the brain during hypoxia and anaemia, and to the carotid body response to hypoxia and hypercapnia. I aimed to develop simple mathematical models of these fail-safe processes and examine their ability to replicate experimental observations. The intent is to demonstrate the validity of applying the fail-safe concept, not to reveal the details of the physiology involved. The model calculations are based on a single compartment of the relevant tissue in each case that is challenged with a decrease in Oxygen Supply. The model equation parameters were adjusted to reproduce experimental observations. The fail-safe model of cerebral blood flow control yielded results similar in form to published experimental observations of the cerebral blood flow responses to hypoxia and anaemia. The fail-safe model of carotid body glomus cell control of intracellular hydrogen ion concentration also yielded results similar in form to observations of carotid sinus nerve responses to hypoxia and hypercapnia. The ability of these simple models to simulate experimental observations demonstrates the applicability of the fail-safe concept to Oxygen delivery. I suggest that a fail-safe view of Oxygen delivery provides novel physiological insight.
Wenfang Dou - One of the best experts on this subject based on the ideXlab platform.
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a two stage Oxygen Supply strategy for enhanced l arginine production by corynebacterium crenatum based on metabolic fluxes analysis
Biochemical Engineering Journal, 2009Co-Authors: Wenfang Dou, Xiaomei Zhang, Zhiming Rao, Zhongping ShiAbstract:Abstract In this study, the metabolic flux distribution analysis of a new l -arginine (Arg) overproducing strain, Corynebacterium crenatum, was carried out under various Oxygen Supply conditions in order to explore the optimized Oxygen Supply profile. The metabolic flux analysis indicated that a relatively higher l -arginine production could be obtained under high Oxygen Supply (HOS) condition overall. However, during the late fermentation phases, a much more stable l -arginine production could be rather achieved under medium Oxygen Supply (MOS) condition. As a result, a two-stage Oxygen Supply strategy, which maintained HOS condition during early fermentation phase, and then step-wisely reduced agitation to keep a stable, smooth and moderate dissolve Oxygen levels (DO) changing profile throughout the production phases, was proposed. With the proposed control strategy, the final l -arginine concentration of the batch fermentation was largely increased and reached to a high level of 36.6 g L−1, which was 16% and 51% higher than those obtained under the HOS and MOS conditions. The two-stage Oxygen Supply strategy could also accelerate glucose consumption rate and thus shorten fermentation time under the same batch initial fermentation condition. The relevant metabolic flux analysis verified the effectiveness of the proposed control strategy.
