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Morphological Differentiation of Streptomyces clavuligerus Exposed to Diverse Environmental Conditions and Its Relationship with Clavulanic Acid Biosynthesis. Processes (Basel) 2020. [DOI: 10.3390/pr8091038] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Clavulanic acid (CA) is a potent inhibitor of class A β-lactamase enzymes produced by Streptomyces clavuligerus (S. clavuligerus) as a defense mechanism. Due to its industrial interest, the process optimization is under continuous investigation. This work aimed at identifying the potential relationship that might exist between S. clavuligerus ATCC 27064 morphology and CA biosynthesis. For this, modified culture conditions such as source, size, and age of inoculum, culture media, and geometry of fermentation flasks were tested. We observed that high density spore suspensions (1 × 107 spores/mL) represent the best inoculum source for S. clavuligerus cell suspension culture. Further, we studied the life cycle of S. clavuligerus in liquid medium, using optic, confocal, and electron microscopy; results allowed us to observe a potential relationship that might exist between the accumulation of CA and the morphology of disperse hyphae. Reactor geometries that increase shear stress promote smaller pellets and a quick disintegration of these in dispersed secondary mycelia, which begins the pseudosporulation process, thus easing CA accumulation. These outcomes greatly contribute to improving the understanding of antibiotic biosynthesis in the Streptomyces genus.
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2
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Li X, Chu J, Jensen PR. The Expression of NOX From Synthetic Promoters Reveals an Important Role of the Redox Status in Regulating Secondary Metabolism of Saccharopolyspora erythraea. Front Bioeng Biotechnol 2020; 8:818. [PMID: 32766231 PMCID: PMC7379104 DOI: 10.3389/fbioe.2020.00818] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 06/26/2020] [Indexed: 12/17/2022] Open
Abstract
Redox cofactors play a pivotal role in primary cellular metabolism, whereas the clear link between redox status and secondary metabolism is still vague. In this study we investigated effects of redox perturbation on the production of erythromycin in Saccharopolyspora erythraea by expressing the water-forming NADH oxidase (NOX) from Streptococcus pneumonia at different levels with synthetic promoters. The expression of NOX reduced the intracellular [NADH]/[NAD+] ratio significantly in S. erythraea which resulted in an increased production of erythromycin by 19∼29% and this increment rose to 60% as more oxygen was supplied. In contrast, the lower redox ratio resulted in a decreased production of another secondary metabolite, the reddish pigment 7-O-rahmnosyl flaviolin. The metabolic shifts of secondary metabolism results in a higher NADH availability which compensates for its oxidization via NOX. The expression of the erythromycin biosynthesis gene cluster (BGC) in the NOX-expression strains was upregulated as the activity of diguanylate cyclase was inhibited moderately by NADH. This study also suggested that lower intracellular [NADH]/[NAD+] ratio benefits the biosynthesis of erythromycin by potentially affecting the biosynthesis of the secondary messenger, bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP), which may stimulate the positive regulation of erythromycin BGC via BldD. The present work provides a basis for future cofactor manipulation in S. erythraea to improve the industrial production of erythromycin.
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Affiliation(s)
- Xiaobo Li
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China.,National Food Institute, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Ju Chu
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Peter R Jensen
- National Food Institute, Technical University of Denmark, Kongens Lyngby, Denmark
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3
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Oxygen Uptake Rate Controlling Strategy Balanced with Oxygen Supply for Improving Coenzyme Q10 Production by Rhodobacter sphaeroides. BIOTECHNOL BIOPROC E 2020. [DOI: 10.1007/s12257-019-0461-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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4
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Zacchetti B, Wösten HA, Claessen D. Multiscale heterogeneity in filamentous microbes. Biotechnol Adv 2018; 36:2138-2149. [DOI: 10.1016/j.biotechadv.2018.10.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 09/15/2018] [Accepted: 10/01/2018] [Indexed: 12/20/2022]
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5
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Liu X, Yang S, Wang F, Dai X, Yang Y, Bai Z. RETRACTED ARTICLE: Comparative analysis of the Corynebacterium glutamicum transcriptome in response to changes in dissolved oxygen levels. ACTA ACUST UNITED AC 2017; 44:181-195. [DOI: 10.1007/s10295-016-1854-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 10/30/2016] [Indexed: 12/13/2022]
Abstract
Abstract
The dissolved oxygen (DO) level of a culture of Corynebacterium glutamicum (C. glutamicum) in a bioreactor has a significant impact on the cellular redox potential and the distribution of energy and metabolites. In this study, to gain a deeper understanding of the effects of DO on the metabolism of C. glutamicum, we sought to systematically explore the influence of different DO concentrations on genetic regulation and metabolism through transcriptomic analysis. The results revealed that after 20 h of fermentation, oxygen limitation enhanced the glucose metabolism, pyruvate metabolism and carbon overflow, and restricted NAD+ availability. A high oxygen supply enhanced the TCA cycle and reduced glyoxylate metabolism. Several key genes involved in response of C. glutamicum to different oxygen concentrations were examined, which provided suggestions for target site modifications in developing optimized oxygen supply strategies. These data provided new insights into the relationship between oxygen supply and metabolism of C. glutamicum.
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Affiliation(s)
- Xiuxia Liu
- grid.258151.a 0000000107081323 National Engineering Laboratory for Cereal Fermentation Technology Jiangnan University 214122 Wuxi China
- grid.258151.a 0000000107081323 The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology Jiangnan University 214122 Wuxi China
- grid.258151.a 0000000107081323 The Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology Jiangnan University 214122 Wuxi China
| | - Sun Yang
- grid.258151.a 0000000107081323 National Engineering Laboratory for Cereal Fermentation Technology Jiangnan University 214122 Wuxi China
- grid.258151.a 0000000107081323 The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology Jiangnan University 214122 Wuxi China
- grid.258151.a 0000000107081323 The Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology Jiangnan University 214122 Wuxi China
| | - Fen Wang
- grid.258151.a 0000000107081323 National Engineering Laboratory for Cereal Fermentation Technology Jiangnan University 214122 Wuxi China
- grid.258151.a 0000000107081323 The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology Jiangnan University 214122 Wuxi China
- grid.258151.a 0000000107081323 The Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology Jiangnan University 214122 Wuxi China
| | - Xiaofeng Dai
- grid.258151.a 0000000107081323 National Engineering Laboratory for Cereal Fermentation Technology Jiangnan University 214122 Wuxi China
- grid.258151.a 0000000107081323 The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology Jiangnan University 214122 Wuxi China
- grid.258151.a 0000000107081323 The Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology Jiangnan University 214122 Wuxi China
| | - Yankun Yang
- grid.258151.a 0000000107081323 National Engineering Laboratory for Cereal Fermentation Technology Jiangnan University 214122 Wuxi China
- grid.258151.a 0000000107081323 The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology Jiangnan University 214122 Wuxi China
- grid.258151.a 0000000107081323 The Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology Jiangnan University 214122 Wuxi China
| | - Zhonghu Bai
- grid.258151.a 0000000107081323 National Engineering Laboratory for Cereal Fermentation Technology Jiangnan University 214122 Wuxi China
- grid.258151.a 0000000107081323 The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology Jiangnan University 214122 Wuxi China
- grid.258151.a 0000000107081323 The Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology Jiangnan University 214122 Wuxi China
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6
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Ser HL, Law JWF, Chaiyakunapruk N, Jacob SA, Palanisamy UD, Chan KG, Goh BH, Lee LH. Fermentation Conditions that Affect Clavulanic Acid Production in Streptomyces clavuligerus: A Systematic Review. Front Microbiol 2016; 7:522. [PMID: 27148211 PMCID: PMC4840625 DOI: 10.3389/fmicb.2016.00522] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 03/29/2016] [Indexed: 12/02/2022] Open
Abstract
The β-lactamase inhibitor, clavulanic acid is frequently used in combination with β-lactam antibiotics to treat a wide spectrum of infectious diseases. Clavulanic acid prevents drug resistance by pathogens against these β-lactam antibiotics by preventing the degradation of the β-lactam ring, thus ensuring eradication of these harmful microorganisms from the host. This systematic review provides an overview on the fermentation conditions that affect the production of clavulanic acid in the firstly described producer, Streptomyces clavuligerus. A thorough search was conducted using predefined terms in several electronic databases (PubMed, Medline, ScienceDirect, EBSCO), from database inception to June 30th 2015. Studies must involve wild-type Streptomyces clavuligerus, and full texts needed to be available. A total of 29 eligible articles were identified. Based on the literature, several factors were identified that could affect the production of clavulanic acid in S. clavuligerus. The addition of glycerol or other vegetable oils (e.g., olive oil, corn oil) could potentially affect clavulanic acid production. Furthermore, some amino acids such as arginine and ornithine, could serve as potential precursors to increase clavulanic acid yield. The comparison of different fermentation systems revealed that fed-batch fermentation yields higher amounts of clavulanic acid as compared to batch fermentation, probably due to the maintenance of substrates and constant monitoring of certain entities (such as pH, oxygen availability, etc.). Overall, these findings provide vital knowledge and insight that could assist media optimization and fermentation design for clavulanic acid production in S. clavuligerus.
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Affiliation(s)
- Hooi-Leng Ser
- School of Pharmacy, Monash University MalaysiaBandar Sunway, Malaysia
- Biomedical Research Laboratory, Jeffrey Cheah School of Medicine and Health Sciences, Monash University MalaysiaBandar Sunway, Malaysia
| | - Jodi Woan-Fei Law
- School of Pharmacy, Monash University MalaysiaBandar Sunway, Malaysia
- Biomedical Research Laboratory, Jeffrey Cheah School of Medicine and Health Sciences, Monash University MalaysiaBandar Sunway, Malaysia
| | - Nathorn Chaiyakunapruk
- School of Pharmacy, Monash University MalaysiaBandar Sunway, Malaysia
- Department of Pharmacy Practice, Faculty of Pharmaceutical Sciences, Center of Pharmaceutical Outcomes Research, Naresuan UniversityPhitsanulok, Thailand
- School of Pharmacy, University of Wisconsin–MadisonMadison, WI, USA
- School of Population Health, University of QueenslandBrisbane, QLD, Australia
| | | | - Uma Devi Palanisamy
- Biomedical Research Laboratory, Jeffrey Cheah School of Medicine and Health Sciences, Monash University MalaysiaBandar Sunway, Malaysia
| | - Kok-Gan Chan
- Division of Genetics and Molecular Biology, Faculty of Science, Institute of Biological Sciences, University of MalayaKuala Lumpur, Malaysia
| | - Bey-Hing Goh
- School of Pharmacy, Monash University MalaysiaBandar Sunway, Malaysia
- Biomedical Research Laboratory, Jeffrey Cheah School of Medicine and Health Sciences, Monash University MalaysiaBandar Sunway, Malaysia
- Center of Health Outcomes Research and Therapeutic Safety (Cohorts), School of Pharmaceutical Sciences, University of PhayaoPhayao, Thailand
| | - Learn-Han Lee
- School of Pharmacy, Monash University MalaysiaBandar Sunway, Malaysia
- Biomedical Research Laboratory, Jeffrey Cheah School of Medicine and Health Sciences, Monash University MalaysiaBandar Sunway, Malaysia
- Center of Health Outcomes Research and Therapeutic Safety (Cohorts), School of Pharmaceutical Sciences, University of PhayaoPhayao, Thailand
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7
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Enhanced Adenosine Production by Bacillus subtilis at Condition with Comprehensively Controlled Dissolved Oxygen and pH During Fermentation. ACTA ACUST UNITED AC 2015. [DOI: 10.1007/978-3-662-45657-6_46] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/11/2023]
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8
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van Dissel D, Claessen D, van Wezel GP. Morphogenesis of Streptomyces in submerged cultures. ADVANCES IN APPLIED MICROBIOLOGY 2014; 89:1-45. [PMID: 25131399 DOI: 10.1016/b978-0-12-800259-9.00001-9] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Members of the genus Streptomyces are mycelial bacteria that undergo a complex multicellular life cycle and propagate via sporulation. Streptomycetes are important industrial microorganisms, as they produce a plethora of medically relevant natural products, including the majority of clinically important antibiotics, as well as a wide range of enzymes with industrial application. While development of Streptomyces in surface-grown cultures is well studied, relatively little is known of the parameters that determine morphogenesis in submerged cultures. Here, growth is characterized by the formation of mycelial networks and pellets. From the perspective of industrial fermentations, such mycelial growth is unattractive, as it is associated with slow growth, heterogeneous cultures, and high viscosity. Here, we review the current insights into the genetic and environmental factors that determine mycelial growth and morphology in liquid-grown cultures. The genetic factors include cell-matrix proteins and extracellular polymers, morphoproteins with specific roles in liquid-culture morphogenesis, with the SsgA-like proteins as well-studied examples, and programmed cell death. Environmental factors refer in particular to those dictated by process engineering, such as growth media and reactor set-up. These insights are then integrated to provide perspectives as to how this knowledge can be applied to improve streptomycetes for industrial applications.
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Affiliation(s)
- Dino van Dissel
- Molecular Biotechnology, Institute Biology Leiden, Leiden University, Leiden, The Netherlands
| | - Dennis Claessen
- Molecular Biotechnology, Institute Biology Leiden, Leiden University, Leiden, The Netherlands.
| | - Gilles P van Wezel
- Molecular Biotechnology, Institute Biology Leiden, Leiden University, Leiden, The Netherlands.
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9
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Genome-wide analysis of the regulation of pimaricin production in Streptomyces natalensis by reactive oxygen species. Appl Microbiol Biotechnol 2014; 98:2231-41. [PMID: 24413916 DOI: 10.1007/s00253-013-5455-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Revised: 12/03/2013] [Accepted: 12/04/2013] [Indexed: 12/20/2022]
Abstract
To investigate the molecular mechanisms that interplay between oxygen metabolism and secondary metabolism in Streptomyces natalensis, we compared the transcriptomes of the strains CAM.02 (ΔsodF), pimaricin under-producer phenotype, and CAM.04 (ΔahpCD), pimaricin over-producer phenotype, with that of the wild type at late exponential and stationary growth phases. Microarray data interpretation was supported by characterization of the mutant strains regarding enzymatic activities, phosphate uptake, oxygen consumption and pimaricin production.Both mutant strains presented a delay in the transcription activation of the PhoRP system and pimaricin biosynthetic gene cluster that correlated with the delayed inorganic phosphate (Pi) depletion in the medium and late onset of pimaricin production, respectively. The carbon flux of both mutants was also altered: a re-direction from glycolysis to the pentose phosphate pathway (PPP) in early exponential phase followed by a transcriptional activation of both pathways in subsequent growth phases was observed. Mutant behavior diverged at the respiratory chain/tricarboxylic acid cycle (TCA) and the branched chain amino acid (BCAA) metabolism. CAM.02 (ΔsodF) presented an impaired TCA cycle and an inhibition of the BCAA biosynthesis and degradation pathways. Conversely, CAM.04 (ΔahpCD) presented a global activation of BCAA metabolism.The results highlight the cellular NADPH/NADH ratio and the availability of biosynthetic precursors via the BCAA metabolism as the main pimaricin biosynthetic bottlenecks under oxidative stress conditions. Furthermore, new evidences are provided regarding a crosstalk between phosphate metabolism and oxidative stress in Streptomyces.
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10
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A universally applicable and rapid method for measuring the growth of streptomyces and other filamentous microorganisms by methylene blue adsorption-desorption. Appl Environ Microbiol 2013; 79:4499-502. [PMID: 23666340 DOI: 10.1128/aem.00778-13] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Quantitative assessment of growth of filamentous microorganisms, such as streptomycetes, is generally restricted to determination of dry weight. Here, we describe a straightforward methylene blue-based sorption assay to monitor microbial growth quantitatively, simply, and rapidly. The assay is equally applicable to unicellular and filamentous bacterial and eukaryotic microorganisms.
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11
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Spadiut O, Rittmann S, Dietzsch C, Herwig C. Dynamic process conditions in bioprocess development. Eng Life Sci 2013. [DOI: 10.1002/elsc.201200026] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- Oliver Spadiut
- Vienna University of Technology; Institute of Chemical Engineering; Research Area Biochemical Engineering; Vienna; Austria
| | - Simon Rittmann
- Vienna University of Technology; Institute of Chemical Engineering; Research Area Biochemical Engineering; Vienna; Austria
| | - Christian Dietzsch
- Vienna University of Technology; Institute of Chemical Engineering; Research Area Biochemical Engineering; Vienna; Austria
| | - Christoph Herwig
- Vienna University of Technology; Institute of Chemical Engineering; Research Area Biochemical Engineering; Vienna; Austria
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12
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Yegneswaran PK, Gray MR, Thompson BG. Experimental simulation of dissolved oxygen fluctuations in large fermentors: effect on Streptomyces clavuligerus. Biotechnol Bioeng 2012; 38:1203-9. [PMID: 18600716 DOI: 10.1002/bit.260381012] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
An experimental Monte Carlo method was used to study the effect of fluctuations in oxygen concentration on the synthesis of antibiotics by Streptomyces clavuligerus. Air was supplied to the culture in a 2-L fermentor in random cycles following the lognormal distribution in order to model the circulation within large production-scale vessels. Each cycle consisted of air supply for 5 s followed by no aeration for the balance of the cycle time which ranged from 8 to 44 s, with a mean time of 20 s. Comparable experiments were also conducted with constant period cycling of air and with continuous supply of air. The yields of cephamycin C and its precursor, penicillin N, were suppressed by the Monte Carlo simulation of circulation in a large tank, as compared to constant period cycling. The concentration of dissolved oxygen remained at a low, ca. 5% of saturation, for 5-10 h longer during the Monte Carlo experiment than during the periodic aeration experiment. The biosynthetic enzymes, which are sensitive to oxygen levels, were likely affected not only by the mean time of cycling but also by the distribution of the cycles.
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Affiliation(s)
- P K Yegneswaran
- Department of Chemical Engineering, University of Alberta, Edmonton, Canada T6G 2G6
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13
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Suphantharika M, Ison AP, Lilly MD, Buckland BC. The influence of dissolved oxygen tension on the synthesis of the antibiotic difficidin by bacillus subtilis. Biotechnol Bioeng 2012; 44:1007-12. [PMID: 18618920 DOI: 10.1002/bit.260440818] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The antibiotic, difficidin, and its hydroxylated derivative oxydifficidin, were synthesized by cultures of Bacillus subtilis grown on a complex medium. Maximum titers of about 200 and 130 mg/L, respectively, were obtained. In fermentations where the dissolved oxygen tension (DOT) was controlled, the maximum specific growth rate was only reduced below 5% air saturation. DOT had little effect on the volumetric rateof synthesis of oxydifficidin but greatly influenced the rate for difficidin, which was reduced at DOT values below 40% air saturation. (c) 1994 John Wiley & Sons, Inc.
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Affiliation(s)
- M Suphantharika
- The Advanced Centre for Biochemical Engineering, Department of Chemical and Biochemical Engineering, University College London, Torrington Place, London WC1E 7JE, United Kingdom
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Yang YK, Morikawa M, Shimizu H, Shioya S, Suga K, Nihira T, Yamada Y. Maximum virginiamycin production by optimization of cultivation conditions in batch culture with autoregulator addition. Biotechnol Bioeng 2012; 49:437-44. [PMID: 18623599 DOI: 10.1002/(sici)1097-0290(19960220)49:4<437::aid-bit11>3.0.co;2-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A strategy for optimization of non-growth-associated production in batch culture employing an empirical approach was developed through the study of virginiamycin production. The strategy is formulated with two aims: attaining a high cell concentration at the beginning of the production phase without decrease in production activity; and enhancing the production activity during the production phase. As a practical example, the goal of a maximum virginiamycin (M and S) production in the batch culture of Streptomyces virginiae was set. To attain a high cell concentration in the production phase of the batch culture, that is, to extend the growth phase for as long as possible, the optimum composition and concentration of the complex medium, especially the yeast extract (YE) concentration, were first investigated. Dissolved oxygen (DO) concentration control was also a parameter considered in maintaining the production activity during the production phase. In addition, to enhance the production activity, an optimum addition strategy of an autoregulator, virginiae butanolide-C (VB-C), was investigated. Combining these measures, the optimum cultivation conditions were found to be an initial YE concentration in the complex medium of 45 g/L, the shot addition of 300 mug/L of VB-C 11.5 h after the start of the batch culture, and a DO concentration maintained above 2 mg/L. The maximum concentrations of virginiamycin M and S were about ninefold those obtained under nonoptimum cultivation conditions. Nonoptimum cultivation conditions consisted of an initial YE concentration one sixth (7.5 g/L) that of the optimum cultivation conditions, and no VB-C addition. These conditions were used as representative of the standard cultivation of virginiamycin in this study. The strategy developed here will be applicable to the production of other antibiotics, especially to the cultivation of Streptomyces species, in which a hormonelike signal material (an autoregulator) plays an important role in antibiotic production. (c) 1996 John Wiley & Sons, Inc.
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Affiliation(s)
- Y K Yang
- Department of Biotechnology, Faculty of Engineering, Osaka University, Suita Osaka 565, Japan
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15
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Decoupling of oxygen transfer and power dissipation for the study of the production of pristinamycins by Streptomyces pristinaespiralis in shaking flasks. Biochem Eng J 2012. [DOI: 10.1016/j.bej.2012.06.021] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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16
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Olmos E, Mehmood N, Haj Husein L, Goergen JL, Fick M, Delaunay S. Effects of bioreactor hydrodynamics on the physiology of Streptomyces. Bioprocess Biosyst Eng 2012; 36:259-72. [PMID: 22923137 DOI: 10.1007/s00449-012-0794-1] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2012] [Accepted: 07/19/2012] [Indexed: 02/02/2023]
Abstract
Streptomyces are filamentous bacteria which are widely used industrially for the production of therapeutic biomolecules, especially antibiotics. Bioreactor operating conditions may impact the physiological response of Streptomyces especially agitation and aeration as they influence hydromechanical stress, oxygen and nutrient transfer. The understanding of the coupling between physiological response and bioreactor hydrodynamics lies on a simultaneous description of the flow and transfers encountered by the bacteria and of the microbial response in terms of growth, consumption, morphology, production or intracellular signals. This article reviews the experimental and numerical works dedicated to the study of the coupling between bioreactor hydrodynamics and antibiotics producing Streptomyces. In a first part, the description of hydrodynamics used in these works is presented and then the main relations used. In a second part, the assumptions made in these works are discussed and put into emphasize. Lastly, the various Streptomyces physiological responses observed are detailed and compared.
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Affiliation(s)
- E Olmos
- CNRS, 54505, Vandoeuvre-lès-Nancy, France.
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17
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Hüttel S, Müller R. Methods to optimize myxobacterial fermentations using off-gas analysis. Microb Cell Fact 2012; 11:59. [PMID: 22571441 PMCID: PMC3445963 DOI: 10.1186/1475-2859-11-59] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2012] [Accepted: 05/09/2012] [Indexed: 11/12/2022] Open
Abstract
Background The influence of carbon dioxide and oxygen on microbial secondary metabolite producers and the maintenance of these two parameters at optimal levels have been studied extensively. Nevertheless, most studies have focussed on their influence on specific product formation and condition optimization of established processes. Considerably less attention has been paid to the influence of reduced or elevated carbon dioxide and oxygen levels on the overall metabolite profiles of the investigated organisms. The synergistic action of both gases has garnered even less attention. Results We show that the composition of the gas phase is highly important for the production of different metabolites and present a simple approach that enables the maintenance of defined concentrations of both O2 and CO2 during bioprocesses over broad concentration ranges with a minimal instrumental setup by using endogenously produced CO2. The metabolite profiles of a myxobacterium belonging to the genus Chondromyces grown under various concentrations of CO2 and O2 showed considerable differences. Production of two unknown, highly cytotoxic compounds and one antimicrobial substance was found to increase depending on the gas composition. In addition, the observation of CO2 and O2 in the exhaust gas allowed optimization and control of production processes. Conclusions Myxobacteria are becoming increasingly important due to their potential for bioactive secondary metabolite production. Our studies show that the influence of different gas partial pressures should not be underestimated during screening processes for novel compounds and that our described method provides a simple tool to investigate this question.
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Affiliation(s)
- Stephan Hüttel
- Department of Pharmaceutical Biotechnology, Saarland University, Saarbruecken, Germany
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18
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Li L, Chen X, Cheng J, Zhang C, Bai J, Chen Y, Niu H, Ying H. Bi-stage control of dissolved oxygen to enhance cyclic adenosine monophosphate production by Arthrobacter A302. Bioprocess Biosyst Eng 2012; 35:1281-6. [PMID: 22382444 DOI: 10.1007/s00449-012-0715-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2011] [Accepted: 02/20/2012] [Indexed: 11/26/2022]
Abstract
Experiments confirmed dissolved oxygen (DO) definitely affects cyclic adenosine monophosphate (cAMP) production by Arthrobacter A302. Production of cAMP by batch fermentation was investigated under various DO conditions. A two-stage DO control strategy was proposed to achieve optimal production of cAMP based on the kinetic analysis: the DO level was controlled at 40% during the first 18 h and then switched to 30%. Relatively high cAMP production (9.9 g L(-1)) was achieved by applying this strategy. The cAMP productivity (0.14 g L(-1) h(-1)) was also successfully improved by 85.1, 59.3, 15.1 and 28.0%, compared to cases in which DO was uncontrolled or DO levels were held at 20, 30 and 40%, respectively. This is the first report of the use of a two-stage DO control strategy in cAMP production, and it was verified to be an effective method for enhancing the cAMP yield via this strain.
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Affiliation(s)
- Lei Li
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Life Science and Pharmaceutical Engineering, Nanjing University of Technology, Nanjing, People's Republic of China
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Beites T, Pires SDS, Santos CL, Osório H, Moradas-Ferreira P, Mendes MV. Crosstalk between ROS homeostasis and secondary metabolism in S. natalensis ATCC 27448: modulation of pimaricin production by intracellular ROS. PLoS One 2011; 6:e27472. [PMID: 22114674 PMCID: PMC3219662 DOI: 10.1371/journal.pone.0027472] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2011] [Accepted: 10/17/2011] [Indexed: 11/24/2022] Open
Abstract
Streptomyces secondary metabolism is strongly affected by oxygen availability. The increased culture aeration enhances pimaricin production in S. natalensis, however the excess of O2 consumption can lead to an intracellular ROS imbalance that is harmful to the cell. The adaptive physiological response of S. natalensis upon the addition of exogenous H2O2 suggested that the modulation of the intracellular ROS levels, through the activation of the H2O2 inducible catalase during the late exponential growth phase, can alter the production of pimaricin. With the construction of defective mutants on the H2O2 related enzymes SodF, AhpCD and KatA1, an effective and enduring modulation of intracellular ROS was achieved. Characterization of the knock-out strains revealed different behaviours regarding pimaricin production: whilst the superoxide dismutase defective mutant presented low levels of pimaricin production compared to the wild-type, the mutants defective on the H2O2-detoxifying enzymes displayed a pimaricin overproducer phenotype. Using physiological and molecular approaches we report a crosstalk between oxidative stress and secondary metabolism regulatory networks. Our results reveal that the redox-based regulation network triggered by an imbalance of the intracellular ROS homeostasis is also able to modulate the biosynthesis of pimaricin in S. natalensis.
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Affiliation(s)
- Tiago Beites
- IBMC – Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
- Departamento de Biologia, Faculdade de Ciências (FCUP), Universidade do Porto, Porto, Portugal
| | - Sílvia D. S. Pires
- IBMC – Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
- ICBAS – Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Catarina L. Santos
- IBMC – Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Hugo Osório
- IPATIMUP - Institute of Molecular Pathology and Immunology, University of Porto, Porto, Portugal
| | - Pedro Moradas-Ferreira
- IBMC – Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
- ICBAS – Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Marta V. Mendes
- IBMC – Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
- * E-mail:
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Yu WB, Gao SH, Yin CY, Zhou Y, Ye BC. Comparative transcriptome analysis of Bacillus subtilis responding to dissolved oxygen in adenosine fermentation. PLoS One 2011; 6:e20092. [PMID: 21625606 PMCID: PMC3097244 DOI: 10.1371/journal.pone.0020092] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2011] [Accepted: 04/12/2011] [Indexed: 12/20/2022] Open
Abstract
Dissolved oxygen (DO) is an important factor for adenosine fermentation. Our previous experiments have shown that low oxygen supply in the growth period was optimal for high adenosine yield. Herein, to better understand the link between oxygen supply and adenosine productivity in B. subtilis (ATCC21616), we sought to systematically explore the effect of DO on genetic regulation and metabolism through transcriptome analysis. The microarrays representing 4,106 genes were used to study temporal transcript profiles of B. subtilis fermentation in response to high oxygen supply (agitation 700 r/min) and low oxygen supply (agitation 450 r/min). The transcriptome data analysis revealed that low oxygen supply has three major effects on metabolism: enhance carbon metabolism (glucose metabolism, pyruvate metabolism and carbon overflow), inhibit degradation of nitrogen sources (glutamate family amino acids and xanthine) and purine synthesis. Inhibition of xanthine degradation was the reason that low oxygen supply enhanced adenosine production. These provide us with potential targets, which can be modified to achieve higher adenosine yield. Expression of genes involved in energy, cell type differentiation, protein synthesis was also influenced by oxygen supply. These results provided new insights into the relationship between oxygen supply and metabolism.
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Affiliation(s)
- Wen-Bang Yu
- Lab of Biosystems and Microanalysis, State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Shu-Hong Gao
- Lab of Biosystems and Microanalysis, State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Chun-Yun Yin
- Lab of Biosystems and Microanalysis, State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Ying Zhou
- Lab of Biosystems and Microanalysis, State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Bang-Ce Ye
- Lab of Biosystems and Microanalysis, State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
- * E-mail:
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Mehmood N, Olmos E, Goergen JL, Blanchard F, Ullisch D, Klöckner W, Büchs J, Delaunay S. Oxygen supply controls the onset of pristinamycins production by Streptomyces pristinaespiralis in shaking flasks. Biotechnol Bioeng 2011; 108:2151-61. [PMID: 21520016 DOI: 10.1002/bit.23177] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2011] [Revised: 03/22/2011] [Accepted: 04/12/2011] [Indexed: 11/12/2022]
Abstract
Antibiotics are secondary metabolites, generally produced during stationary phase of growth under different nutritional and hydrodynamic stresses. However, the exact mechanisms of the induction of antibiotics production are still not clearly established. In a previous study, the induction of pristinamycins production by Streptomyces pristinaespiralis as well as product concentrations were correlated with power dissipation per unit of volume (P/V) in shaking flasks. In this study, detailed kinetics of growth, substrate consumption, oxygen transfer rate and pristinamycins production under varying P/V conditions have been obtained and analyzed. Our results showed that higher P/V resulted in a higher concentration of biomass and promoted an earlier nutrient limitation and ultimately an earlier induction of pristinamycins production. The maximal specific growth rate, specific oxygen consumption rate and specific consumption rate of glutamate increased with P/V while influence was less marked with specific consumption rate of glucose, arginine, ammonium ions and phosphate. When oxygen uptake rate (OUR) was limited by free-surface oxygen transfer, pristinamycins production was not detected despite the occurrence of nitrogen and/or phosphate sources limitation. The threshold value for OUR observed was around 25 mmol L(-1) h(-1). This suggested that a limitation in nitrogen and/or phosphate alone was not sufficient to induce pristinamycins production by S. pristinaespiralis pr11. To induce this production, the oxygen transfer had to be non-limiting.
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Affiliation(s)
- N Mehmood
- Laboratoire Réactions et Génie des Procédés-UPR CNRS 3349, Nancy-Université, ENSAIA-INPL, 2 Avenue de la Forêt de Haye B.P. 172 F-54505 Vandœuvre lès Nancy, France
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22
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Ertunc S, Akay B, Boyacioglu H, Hapoglu H. Self-tuning control of dissolved oxygen concentration in a batch bioreactor. FOOD AND BIOPRODUCTS PROCESSING 2009. [DOI: 10.1016/j.fbp.2008.04.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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23
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Pereira DG, Tonso A, Kilikian BV. Effect of dissolved oxygen concentration on red pigment and citrinin production by Monascus purpureus ATCC 36928. BRAZILIAN JOURNAL OF CHEMICAL ENGINEERING 2008. [DOI: 10.1590/s0104-66322008000200004] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
| | - A. Tonso
- Universidade de São Paulo, Brazil
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24
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Rocha-Valadez JA, Albiter V, Caro MA, Serrano-Carreón L, Galindo E. A fermentation system designed to independently evaluate mixing and/or oxygen tension effects in microbial processes: development, application and performance. Bioprocess Biosyst Eng 2007; 30:115-22. [PMID: 17225992 DOI: 10.1007/s00449-006-0108-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2006] [Accepted: 12/15/2006] [Indexed: 10/23/2022]
Abstract
In order to evaluate the independent effects of hydrodynamic conditions and/or oxygen tension on culture physiology and productivity, a fermentation system designed to control dissolved oxygen at constant power drawn (P/V) was developed. The system included a fully instrumented 14 l bioreactor coupled to a PC for data acquisition and control. Power drawn was measured (using a commercial torquemeter coupled to the shaft) and maintained constant by varying the agitation speed; while gas blending was used to control dissolved oxygen concentration. To validate the system, rheological-complex fermentations involving xanthan gum production and filamentous fungal cultivation (using Xanthomonas campestris and Trichoderma harzianum) were developed. In both cases, and despite the changing environmental conditions (due to increased broth viscosities and microbial respiration), both variables were controlled at the desired set points. Through such a system, a rigorous evaluation of the hydrodynamic conditions and/or oxygen tension on culture physiology and productivity is now feasible.
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Affiliation(s)
- J A Rocha-Valadez
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico
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25
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Chaitali M, Kapadi M, Suraishkumar GK, Gudi RD. Productivity improvement in xanthan gum fermentation using multiple substrate optimization. Biotechnol Prog 2003; 19:1190-8. [PMID: 12892481 DOI: 10.1021/bp0257269] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A novel and more comprehensive formulation of the optimal control problem that reflects the operational requirements of a typical industrial fermentation has been proposed in this work. This formulation has been applied to a fed-batch bioreactor with three control variables, i.e., feed rates of carbon source, nitrogen source, and an oxygen source, to result in a 148.7% increase in product formation. Xanthan gum production using Xanthomonas campestris has been used as the model system for this optimization study, and the liquid-phase oxygen supply strategy has been used to supply oxygen to the fermentation. The formulated optimization problem has several constraints associated with it due to the nature of the system. A robust stochastic technique, differential evolution, has been used to solve this challenging optimization problem. The infinite dimensional optimization problem has been approximated to a finite dimensional one by control vector parametrization. The state constraints that are path constraints have been addressed by using penalty functions and by integrating them over the total duration to ensure a feasible solution. End point constraints on final working volume of the reactor and on the final residual concentrations of carbon and nitrogen sources have been included in the problem formulation. Further, the toxicity of the oxygen source, H(2)O(2), has been addressed by imposing a constraint on its maximum usable concentration. In addition, the initial volume of the bioreactor contents and feed concentrations have been handled as decision variables, which has enabled a well-grounded choice for their values from the optimization procedure; adhoc values are normally used in the industry. All results obtained by simulation have been validated experimentally with good agreements between experimental and simulated values.
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Affiliation(s)
- Mandal Chaitali
- Biochemical Engineering Group, Department of Chemical Engineering, Indian Institute of Technology, Bombay, Powai, Mumbai 400 076, India
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26
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Akay B, Ertunç S, Kahvecioğlu A, Hapoğlu H, Alpbaz M. Adaptive Control of S.cerevisiae Production. FOOD AND BIOPRODUCTS PROCESSING 2002. [DOI: 10.1205/096030802753479089] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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27
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Kapat A, Jung JK, Park YH. Enhancement of glucose oxidase production in batch cultivation of recombinant Saccharomyces cerevisiae: optimization of oxygen transfer condition. J Appl Microbiol 2001; 90:216-22. [PMID: 11168724 DOI: 10.1046/j.1365-2672.2001.01233.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
AIMS To obtain an optimal combination of agitation speed and aeration rate for maximization of specific glucose oxidase (GOD) production in recombinant Saccharomyces cerevisiae, and to establish a correlation between kLa vis-à-vis oxygen transfer condition and specific glucose oxidase production. METHODS AND RESULTS The oxygen transfer condition was manifested indirectly by manipulating the impeller speed and aeration rate in accordance with a Central Composite Rotatory Design (CCRD). The dissolved oxygen concentration and the volumetric oxygen transfer coefficient (kLa) were determined at corresponding combinations of impeller speed and aeration rate. The maximal specific extracellular glucose oxidase production (3.17 U mg-1 dry cell mass) was achieved when the initial dissolved oxygen concentration was 6.83 mg l-1 at the impeller speed of 420 rev min-1 and at the rate of aeration of 0.25 vvm. It was found out that while impeller speed had a direct effect on the production of enzyme, a correlation between kLa and specific GOD production could not be established. CONCLUSION At the agitation speed of 420 rev min-1 and at 0.25 vvm aeration rate, the degree of turbulence and the dissolved oxygen concentration were thought to be optimal both for cellular growth and production of enzyme. SIGNIFICANCE AND IMPACT OF THE STUDY The combined effect of agitation and aeration on recombinant glucose oxidase production in batch cultivation has not yet been reported in the literature. Therefore, this study gives an insight into the effect of these two important physical parameters on recombinant protein production. It also suggests that since there is no correlation between kLa and specific production of GOD, kLa should not be used as one of the scale-up parameters.
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Affiliation(s)
- A Kapat
- Biopilot Plant, Korea Research Institute of Bioscience and Biotechnology, KIST, P.O. Box 115, Yusong, Taejon 305-600, Republic of Korea.
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28
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Heydarian S, Ison A, Lilly M, Ayazi Shamlou P. Turbulent breakage of filamentous bacteria in mechanically agitated batch culture. Chem Eng Sci 2000. [DOI: 10.1016/s0009-2509(99)00449-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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29
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Gomes J, Menawat AS. Precise control of dissolved oxygen in bioreactors – a model-based geometric algorithm. Chem Eng Sci 2000. [DOI: 10.1016/s0009-2509(99)00305-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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30
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Abstract
The dissolved oxygen (DO) is an important variable in aerobic fermentations and affects the cell growth and product formation. Dissolved oxygen control is difficult in batch fermentations because of the time-varying conditions, time delays, and the probe dynamics. Modeling of the various patterns of biological activity in fermentations and their impact on the DO process dynamics is essential to both achieve a satisfactory control and to track the aforementioned patterns. An adaptive pole placement algorithm with time-delay compensation was used for controlling the DO, coupled with system identification using recursively estimated autoregressive models with exogeneous inputs (ARX). The flow rate of O2 in a constant flow rate gas inlet mixture is used as the manipulated variable. Supervision and coordination techniques are applied to improve the control performance. The control performance is affected by the accuracy of the model prediction and the selected time delay. The effect of DO level on the productivity of beta-lactamase using Bacillus subtilis under oxygen-limited conditions is investigated. Beta-lactamase stability is improved under prolonged growth conditions with low DO levels.
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Affiliation(s)
- I G Sargantanis
- Department of Chemical and Bioresource Engineering, Colorado State University, Fort Collins, Colorado 80523, USA
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31
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Ariff A, Salleh M, Ghani B, Hassan M, Rusul G, Karim M. Aeration and yeast extract requirements for kojic acid production by Aspergillus flavus link. Enzyme Microb Technol 1996. [DOI: 10.1016/s0141-0229(96)00065-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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32
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Diaz C, Dieu P, Feuillerat C, Lelong P, Salomé M. Adaptive predictive control of dissolved oxygen concentration in a laboratory-scale bioreactor. J Biotechnol 1995; 43:21-32. [PMID: 8573319 DOI: 10.1016/0168-1656(95)00101-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We present an algorithm for the adaptive control of dissolved oxygen concentration in a bioreactor, based on the agitation rate. The dynamics are represented by an incremental first-order model with variable dead-time and parameters. These are estimated on-line by a recursive least-squares identification method with a forgetting factor and a constant sensitivity. The model is employed to predict the behaviour of the dissolved oxygen concentration over a finite horizon, using an original method which requires little computation. Then, a Generalized Predictive Control optimisation strategy computes the agitation rate from the predictions and the desired set point, while gradually updating the controller smoothness. This algorithm, which requires little preliminary knowledge, has been implemented on a laboratory-scale fed-batch bioreactor for which the use of conventional controllers showed limited performance, due to the unpredictable and evolutive nature of the dynamics. The new controller proved to be robust and effective over a wide range of operating conditions, while requiring no operator adjustments.
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Affiliation(s)
- C Diaz
- Sanofi Recherche, Labège Innopole, France
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33
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Fang A, Demain AL. Dependence of nitrogen- and phosphorus-regulation of beta-lactam antibiotic production by Streptomyces clavuligerus on aeration level. JOURNAL OF INDUSTRIAL MICROBIOLOGY 1995; 15:407-10. [PMID: 8588881 DOI: 10.1007/bf01569965] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Interference with beta-lactam production in Streptomyces clavuligerus by ammonium and phosphate ions, normally observed with optimum levels of aeration, was eliminated by restriction of the air supply. Under such a restriction, ammonium slightly stimulated and phosphate markedly stimulated beta-lactam antibiotic production. These are rare examples of 'regulation reversal' by an environmental modification.
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Affiliation(s)
- A Fang
- Department of Biology, Massachusetts Institute of Technology, Cambridge 02139, USA
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34
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An energy cost minimizing strategy for fermentation dissolved oxygen control. ACTA ACUST UNITED AC 1994. [DOI: 10.1007/bf00393391] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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35
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36
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Ohno A, Ano T, Shoda M. Effect of temperature change and aeration on the production of the antifungal peptide antibiotic iturin by Bacillus subtilis NB22 in liquid cultivation. ACTA ACUST UNITED AC 1993. [DOI: 10.1016/0922-338x(93)90098-s] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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