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Yang M, Liu Z, Wang A, Nopens I, Hu H, Chen H. High biomass yields of Chlorella protinosa with efficient nitrogen removal from secondary effluent in a membrane photobioreactor. J Environ Sci (China) 2024; 146:272-282. [PMID: 38969455 DOI: 10.1016/j.jes.2023.10.036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2023] [Revised: 10/28/2023] [Accepted: 10/29/2023] [Indexed: 07/07/2024]
Abstract
Further treatment of secondary effluents before their discharge into the receiving water bodies could alleviate water eutrophication. In this study, the Chlorella proteinosa was cultured in a membrane photobioreactor to further remove nitrogen from the secondary effluents. The effect of hydraulic retention time (HRT) on microalgae biomass yields and nutrient removal was studied. The results showed that soluble algal products concentration reduced in the suspension at low HRT, thereby alleviating microalgal growth inhibition. In addition, the lower HRT reduced the nitrogen limitation for Chlorella proteinosa's growth through the phase-out of nitrogen-related functional bacteria. As a result, the productivity for Chlorella proteinosa increased from 6.12 mg/L/day at an HRT of 24 hr to 20.18 mg/L/day at an HRT of 8 hr. The highest removal rates of 19.7 mg/L/day, 23.8 mg/L/day, and 105.4 mg/L/day were achieved at an HRT of 8 hr for total nitrogen (TN), ammonia, and chemical oxygen demand (COD), respectively. However, in terms of removal rate, TN and COD were the largest when HRT is 24 hr, which were 74.5% and 82.6% respectively. The maximum removal rate of ammonia nitrogen was 99.2% when HRT was 8 hr.
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Affiliation(s)
- Min Yang
- School of Civil and Environmental Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China; Key Laboratory of Dongting Lake Aquatic Eco-Environmental Control and Restoration of Hunan Province, Changsha 410114, China; BIOMATH, Department of Data Analysis and Mathematical Modelling, Ghent University, Gent B 9000, Belgium
| | - Zhen Liu
- Key Laboratory of Dongting Lake Aquatic Eco-Environmental Control and Restoration of Hunan Province, Changsha 410114, China
| | - Aijie Wang
- School of Civil and Environmental Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China; Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Ingmar Nopens
- BIOMATH, Department of Data Analysis and Mathematical Modelling, Ghent University, Gent B 9000, Belgium
| | - Hairong Hu
- School of Materials Science and Engineering, Hunan University of Science and Technology, Xiangtan 411201, China
| | - Hong Chen
- Key Laboratory of Dongting Lake Aquatic Eco-Environmental Control and Restoration of Hunan Province, Changsha 410114, China.
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Literáková P, Zavřel T, Búzová D, Kaštánek P, Červený J. Marine microalgae Schizochytrium demonstrates strong production of essential fatty acids in various cultivation conditions, advancing dietary self-sufficiency. Front Nutr 2024; 11:1290701. [PMID: 38854161 PMCID: PMC11157098 DOI: 10.3389/fnut.2024.1290701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 05/02/2024] [Indexed: 06/11/2024] Open
Abstract
Introduction Polyunsaturated fatty acids (PUFAs) are essential nutrients that humans obtain from their diet, primarily through fish oil consumption. However, fish oil production is no longer sustainable. An alternative approach is to produce PUFAs through marine microalgae. Despite the potential of algae strains to accumulate high concentrations of PUFAs, including essential fatty acids (EFAs), many aspects of PUFA production by microalgae remain unexplored and their current production outputs are frequently suboptimal. Methods In this study, we optimized biomass and selected ω-3 PUFAs production in two strains of algae, Schizochytrium marinum AN-4 and Schizochytrium limacinum CO3H. We examined a broad range of cultivation conditions, including pH, temperature, stirring intensity, nutrient concentrations, and their combinations. Results We found that both strains grew well at low pH levels (4.5), which could reduce bacterial contamination and facilitate the use of industrial waste products as substrate supplements. Intensive stirring was necessary for rapid biomass accumulation but caused cell disruption during lipid accumulation. Docosahexaenoic acid (DHA) yield was independent of cultivation temperature within a range of 28-34°C. We also achieved high cell densities (up to 9 g/L) and stable DHA production (average around 0.1 g/L/d) under diverse conditions and nutrient concentrations, with minimal nutrients required for stable production including standard sea salt, glucose or glycerol, and yeast extract. Discussion Our findings demonstrate the potential of Schizochytrium strains to boost industrial-scale PUFA production and make it more economically viable. Additionally, these results may pave the way for smaller-scale production of essential fatty acids in a domestic setting. The development of a new minimal culturing medium with reduced ionic strength and antibacterial pH could further enhance the feasibility of this approach.
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Affiliation(s)
- Petra Literáková
- Department of Adaptive Biotechnologies, Global Change Research Institute, The Czech Academy of Sciences, Brno, Czechia
- Department of Biochemistry, Faculty of Science, Masaryk University, Brno, Czechia
| | - Tomáš Zavřel
- Department of Adaptive Biotechnologies, Global Change Research Institute, The Czech Academy of Sciences, Brno, Czechia
| | - Diana Búzová
- Department of Adaptive Biotechnologies, Global Change Research Institute, The Czech Academy of Sciences, Brno, Czechia
| | | | - Jan Červený
- Department of Adaptive Biotechnologies, Global Change Research Institute, The Czech Academy of Sciences, Brno, Czechia
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Schütte L, Hanisch PG, Scheler N, Haböck KC, Huber R, Ersoy F, Berger RG. Squalene production under oxygen limitation by Schizochytrium sp. S31 in different cultivation systems. Appl Microbiol Biotechnol 2024; 108:201. [PMID: 38349390 PMCID: PMC10864429 DOI: 10.1007/s00253-024-13051-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 01/26/2024] [Accepted: 02/02/2024] [Indexed: 02/15/2024]
Abstract
The triterpene squalene is widely used in the food, cosmetics and pharmaceutical industries due to its antioxidant, antistatic and anti-carcinogenic properties. It is usually obtained from the liver of deep sea sharks, which are facing extinction. Alternative production organisms are marine protists from the family Thraustochytriaceae, which produce and store large quantities of various lipids. Squalene accumulation in thraustochytrids is complex, as it is an intermediate in sterol biosynthesis. Its conversion to squalene 2,3-epoxide is the first step in sterol synthesis and is heavily oxygen dependent. Hence, the oxygen supply during cultivation was investigated in our study. In shake flask cultivations, a reduced oxygen supply led to increased squalene and decreased sterol contents and yields. Oxygen-limited conditions were applied to bioreactor scale, where squalene accumulation and growth of Schizochytrium sp. S31 was determined in batch, fed-batch and continuous cultivation. The highest dry matter (32.03 g/L) was obtained during fed-batch cultivation, whereas batch cultivation yielded the highest biomass productivity (0.2 g/L*h-1). Squalene accumulation benefited from keeping the microorganisms in the growth phase. Therefore, the highest squalene content of 39.67 ± 1.34 mg/g was achieved by continuous cultivation (D = 0.025 h-1) and the highest squalene yield of 1131 mg/L during fed-batch cultivation. Volumetric and specific squalene productivity both reached maxima in the continuous cultivation at D = 0.025 h-1 (6.94 ± 0.27 mg/L*h-1 and 1.00 ± 0.03 mg/g*h-1, respectively). Thus, the choice of a suitable cultivation method under oxygen-limiting conditions depends heavily on the process requirements. KEY POINTS: • Measurements of respiratory activity and backscatter light of thraustochytrids • Oxygen limitation increased squalene accumulation in Schizochytrium sp. S31 • Comparison of different cultivation methods under oxygen-limiting conditions.
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Affiliation(s)
- Lina Schütte
- Institute of Food Chemistry, Gottfried Wilhelm Leibniz University Hannover, Hannover, Germany.
| | - Patrick G Hanisch
- Department of Engineering and Management, Munich University of Applied Sciences HM, Munich, Germany
| | - Nina Scheler
- Institute of Food Chemistry, Gottfried Wilhelm Leibniz University Hannover, Hannover, Germany
| | - Katharina C Haböck
- Institute of Food Chemistry, Gottfried Wilhelm Leibniz University Hannover, Hannover, Germany
| | - Robert Huber
- Department of Engineering and Management, Munich University of Applied Sciences HM, Munich, Germany
| | - Franziska Ersoy
- Institute of Food Chemistry, Gottfried Wilhelm Leibniz University Hannover, Hannover, Germany
| | - Ralf G Berger
- Institute of Food Chemistry, Gottfried Wilhelm Leibniz University Hannover, Hannover, Germany
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Liu L, Zhu X, Ye H, Wen Y, Sen B, Wang G. Low dissolved oxygen supply functions as a global regulator of the growth and metabolism of Aurantiochytrium sp. PKU#Mn16 in the early stages of docosahexaenoic acid fermentation. Microb Cell Fact 2023; 22:52. [PMID: 36918882 PMCID: PMC10015696 DOI: 10.1186/s12934-023-02054-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 03/04/2023] [Indexed: 03/16/2023] Open
Abstract
BACKGROUND Thraustochytrids accumulate lipids with a high content of docosahexaenoic acid (DHA). Although their growth and DHA content are significantly affected by the dissolved oxygen (DO) supply, the role of DO on the transcriptional regulation of metabolism and accumulation of intracellular metabolites remains poorly understood. Here we investigate the effects of three different DO supply conditions (10%, 30%, and 50%) on the fed-batch culture of the Aurantiochytrium PKU#Mn16 strain to mainly reveal the differential gene expressions and metabolite profiles. RESULTS While the supply of 10% DO significantly reduced the rates of biomass and DHA production in the early stages of fermentation, it achieved the highest amounts of biomass (56.7 g/L) and DHA (6.0 g/L) on prolonged fermentation. The transcriptome analyses of the early stage (24 h) of fermentation revealed several genes involved in the central carbon, amino acid, and fatty acid metabolism, which were significantly downregulated at a 10% DO level. The comparative metabolomics results revealed the accumulation of several long-chain fatty acids, amino acids, and other metabolites, supporting the transcriptional regulation under the influence of a low oxygen supply condition. In addition, certain genes involved in antioxidative systems were downregulated under 10% DO level, suggesting a lesser generation of reactive oxygen species that lead to oxidative damage and fatty acid oxidation. CONCLUSIONS The findings of this study suggest that despite the slow growth and metabolism in the early stage of fermentation of Aurantiochytrium sp. PKU#Mn16, a constant supply of low dissolved oxygen can yield biomass and DHA content better than that with high oxygen supply conditions. The critical information gained in this study will help to further improve DHA production through bioprocess engineering strategies.
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Affiliation(s)
- Lu Liu
- Center for Marine Environmental Ecology, School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China
| | - Xingyu Zhu
- Center for Marine Environmental Ecology, School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China
| | - Huike Ye
- Center for Marine Environmental Ecology, School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China
| | - Yingying Wen
- Center for Marine Environmental Ecology, School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China
| | - Biswarup Sen
- Center for Marine Environmental Ecology, School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China.
| | - Guangyi Wang
- Center for Marine Environmental Ecology, School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China. .,Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin, 300072, China. .,Center for Biosafety Research and Strategy, Tianjin University, Tianjin, 300072, China.
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Chi G, Xu Y, Cao X, Li Z, Cao M, Chisti Y, He N. Production of polyunsaturated fatty acids by Schizochytrium (Aurantiochytrium) spp. Biotechnol Adv 2021; 55:107897. [PMID: 34974158 DOI: 10.1016/j.biotechadv.2021.107897] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 12/05/2021] [Accepted: 12/20/2021] [Indexed: 12/28/2022]
Abstract
Diverse health benefits are associated with dietary consumption of omega-3 long-chain polyunsaturated fatty acids (ω-3 LC-PUFA), particularly docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). Traditionally, these fatty acids have been obtained from fish oil, but limited supply, variably quality, and an inability to sustainably increase production for a rapidly growing market, are driving the quest for alternative sources. DHA derived from certain marine protists (heterotrophic thraustochytrids) already has an established history of commercial production for high-value dietary use, but is too expensive for use in aquaculture feeds, a much larger potential market for ω-3 LC-PUFA. Sustainable expansion of aquaculture is prevented by its current dependence on wild-caught fish oil as the source of ω-3 LC-PUFA nutrients required in the diet of aquacultured animals. Although several thraustochytrids have been shown to produce DHA and EPA, there is a particular interest in Schizochytrium spp. (now Aurantiochytrium spp.), as some of the better producers. The need for larger scale production has resulted in development of many strategies for improving productivity and production economics of ω-3 PUFA in Schizochytrium spp. Developments in fermentation technology and metabolic engineering for enhancing LC-PUFA production in Schizochytrium spp. are reviewed.
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Affiliation(s)
- Guoxiang Chi
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China; The Key Laboratory for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen 361005, China
| | - Yiyuan Xu
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China; The Key Laboratory for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen 361005, China
| | - Xingyu Cao
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China; The Key Laboratory for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen 361005, China
| | - Zhipeng Li
- College of Food and Biological Engineering, Jimei University, Xiamen 361000, China
| | - Mingfeng Cao
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China; The Key Laboratory for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen 361005, China.
| | - Yusuf Chisti
- School of Engineering, Massey University, Private Bag 11 222, Palmerston North, New Zealand.
| | - Ning He
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China; The Key Laboratory for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen 361005, China.
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Jo MH, Kim B, Ju JH, Heo SY, Ahn KH, Lee HJ, Yeom HS, Jang H, Kim MS, Kim CH, Oh BR. Tremella fuciformis TFCUV5 Mycelial Culture-derived Exopolysaccharide Production and Its Anti-aging Effects on Skin Cells. BIOTECHNOL BIOPROC E 2021. [DOI: 10.1007/s12257-020-0361-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Thielemann AK, Smetana S, Pleissner D. Cultivation of the heterotrophic microalga Galdieria sulphuraria on food waste: A Life Cycle Assessment. BIORESOURCE TECHNOLOGY 2021; 340:125637. [PMID: 34315124 DOI: 10.1016/j.biortech.2021.125637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 07/11/2021] [Accepted: 07/18/2021] [Indexed: 06/13/2023]
Abstract
The aim of this study was to perform a Life Cycle Assessment of a production process of 1 kg dry algal biomass powder (Galdieria sulphuraria) with 27 % (w/w) protein content for human consumption for optimizing the production regarding global warming potential and resource efficiency in combination with food waste utilization. It was investigated, underpinned by a comparison of the use of conventional glucose, whether and to what extent the environmental impact/global warming potential can be reduced by changing to food waste hydrolysate and how this can lead to a more sustainable use of resources and a sustainable development. Overall, the results showed that hydrolysis, along with freeze-drying, caused most of the overall impact. The carbon footprint associated with the use of hydrolyzed food waste was 11% higher than using conventional glucose and supplementary nutrients mainly driven by the high demand of energy for hydrolysis.
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Affiliation(s)
- Anne Karolin Thielemann
- Sustainable Chemistry (Resource Efficiency), Institute of Sustainable Chemistry, Leuphana University of Lüneburg, Universitätsallee 1, Lüneburg C13.203, 21335, Germany; Institute for Food and Environmental Research e. V., Papendorfer Weg 3, Bad Belzig 14806, Germany
| | - Sergiy Smetana
- German Institute of Food Technologies - DIL e.V., Prof.-von-Klitzing-Str. 7, Quakenbrück 49610, Germany
| | - Daniel Pleissner
- Sustainable Chemistry (Resource Efficiency), Institute of Sustainable Chemistry, Leuphana University of Lüneburg, Universitätsallee 1, Lüneburg C13.203, 21335, Germany; Institute for Food and Environmental Research e. V., Papendorfer Weg 3, Bad Belzig 14806, Germany.
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Gupta A, Barrow CJ, Puri M. Multiproduct biorefinery from marine thraustochytrids towards a circular bioeconomy. Trends Biotechnol 2021; 40:448-462. [PMID: 34627647 DOI: 10.1016/j.tibtech.2021.09.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 09/08/2021] [Accepted: 09/09/2021] [Indexed: 12/18/2022]
Abstract
Microalgal biotechnology research continues to expand due to largely unexplored marine environments and growing consumer interest in healthy products. Thraustochytrids, which are marine oleaginous protists, are known for their production of bioactives with significant applications in nutraceuticals, pharmaceuticals, and aquaculture. A wide range of high-value biochemicals, such as nutritional supplements (omega-3 fatty acids), squalene, exopolysaccharides (EPSs), enzymes, aquaculture feed, and biodiesel and pigment compounds, have been investigated. We discuss thraustochytrids as potential feedstocks to produce various bioactive compounds and advocate developing a biorefinery to offset production costs. We anticipate that future advances in cell manufacturing, lipidomic analysis, and nanotechnology-guided lipid extraction would facilitate large-scale cost-competitive production through these microbes.
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Affiliation(s)
- Adarsha Gupta
- Medical Biotechnology, College of Medicine and Public Health, Flinders University, Bedford Park, 5042, Adelaide, Australia; Flinders Health and Medical Research Institute (FHMRI), Flinders University, Bedford Park, 5042, Adelaide, Australia
| | - Colin J Barrow
- Centre for Chemistry and Biotechnology, School of Life and Environmental Sciences, Deakin University, Waurn Ponds, 3216, Geelong, Australia
| | - Munish Puri
- Medical Biotechnology, College of Medicine and Public Health, Flinders University, Bedford Park, 5042, Adelaide, Australia; Flinders Health and Medical Research Institute (FHMRI), Flinders University, Bedford Park, 5042, Adelaide, Australia; Centre for Chemistry and Biotechnology, School of Life and Environmental Sciences, Deakin University, Waurn Ponds, 3216, Geelong, Australia.
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Thielemann AK, Smetana S, Pleissner D. Life cycle assessment of hetero- and phototrophic as well as combined cultivations of Galdieria sulphuraria. BIORESOURCE TECHNOLOGY 2021; 335:125227. [PMID: 33992913 DOI: 10.1016/j.biortech.2021.125227] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 04/22/2021] [Accepted: 04/23/2021] [Indexed: 05/21/2023]
Abstract
Microalgae cultivation for food purposes could have high environmental impacts. The study performed life cycle assessment (LCA) of hypothetical model combining phototrophic and heterotrophic cultivations, exchanging produced gases (carbon dioxide from heterotrophic and oxygen from autotrophic) as a potential strategy to reduce the environmental impact of microalgae cultivation. The LCA indicated that the production of Galdieria sulphuraria in a combined cultivation system has environmental benefits compared with the separate phototrophic cultivation and an almost twice lower carbon footprint than phototrophic cultivation. The benefits are based on the lower volume of culture broth and consequently reduced energy demand as well as less demanding wastewater treatment of the heterotrophic cultivation. Such combination of cultivation activities could be recommended to the producers dealing with phototrophic cultivation as a sustainable strategy for the environmental impact reduction.
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Affiliation(s)
- Anne Karolin Thielemann
- Sustainable Chemistry (Resource Efficiency), Institute of Sustainable and Environmental Chemistry, Leuphana University of Lüneburg, Universitätsallee 1, C13.203, 21335 Lüneburg, Germany; Institute for Food and Environmental Research e. V., Papendorfer Weg 3, 14806 Bad Belzig, Germany
| | - Sergiy Smetana
- German Institute of Food Technologies - DIL e.V., Prof.-von-Klitzing-Str. 7, 49610 Quakenbrück, Germany
| | - Daniel Pleissner
- Sustainable Chemistry (Resource Efficiency), Institute of Sustainable and Environmental Chemistry, Leuphana University of Lüneburg, Universitätsallee 1, C13.203, 21335 Lüneburg, Germany; Institute for Food and Environmental Research e. V., Papendorfer Weg 3, 14806 Bad Belzig, Germany.
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Sirirak K, Powtongsook S, Suanjit S, Jaritkhuan S. Effectiveness of various bioreactors for thraustochytrid culture and production ( Aurantiochytruim limacinum BUCHAXM 122). PeerJ 2021; 9:e11405. [PMID: 34123585 PMCID: PMC8164841 DOI: 10.7717/peerj.11405] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 04/14/2021] [Indexed: 11/20/2022] Open
Abstract
This study aimed to develop bioreactors for cultivation of thraustochytrid, Aurantiochytrium limacinum BUCHAXM 122, that are low in cost and simple to operate. Obtaining maximum biomass and fatty acid production was a prerequisite. Three bioreactor designs were used: stirred tank bioreactor (STB), bubble bioreactor (BB) and internal loop airlift bioreactor (ILAB). The bioreactors were evaluated for their influence on oxygen mass transfer coefficient (kLa), using various spargers, mixing speed, and aeration rates. Biomass and DHA production from STB, BB, ILAB were then compared with an incubator shaker, using batch culture experiments. Results showed that a bundle of eight super-fine pore air stones was the best type of aeration sparger for all three bioreactors. Optimal culture conditions in STB were 600 rpm agitation speed and 2 vvm aeration rate, while 2 vvm and 1.5 vvm aeration provided highest biomass productivity in BB and ILAB, respectively. Antifoam agent was needed for all reactor types in order to reduce excessive foaming. Results indicated that with optimized conditions, these bioreactors are capable of thraustochytrid cultivation with a similar efficiency as cultivation using a rotary shaker. STB had the highest kLa and provided the highest biomass of 43.05 ± 0.35 g/L at 48 h. BB was simple in design, had low operating costs and was easy to build, but yielded the lowest biomass (27.50 ± 1.56 g/L). ILAB, on the other hand, had lower kLa than STB, but provided highest fatty acid productivity, of 35.36 ± 2.51% TFA.
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Affiliation(s)
- Khanoksinee Sirirak
- Graduate Program in Environmental Science, Faculty of Science, Burapha University, Chon Buri, Thailand
| | - Sorawit Powtongsook
- Center of Excellence for Marine Biotechnology, Department of Marine Science, Faculty of Science, Chulalongkorn University, Bangkok, Thailand.,National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Pathum Thani, Thailand
| | - Sudarat Suanjit
- Department of Microbiology, Faculty of Science, Burapha University, Chon Buri, Thailand
| | - Somtawin Jaritkhuan
- Department of Aquatic Science, Faculty of Science, Burapha University, Chon Buri, Thailand
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Chang M, Zhang T, Li L, Lou F, Ma M, Liu R, Jin Q, Wang X. Choreography of multiple omics reveals the mechanism of lipid turnover in Schizochytrium sp. S31. ALGAL RES 2021. [DOI: 10.1016/j.algal.2021.102182] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Du F, Wang YZ, Xu YS, Shi TQ, Liu WZ, Sun XM, Huang H. Biotechnological production of lipid and terpenoid from thraustochytrids. Biotechnol Adv 2021; 48:107725. [PMID: 33727145 DOI: 10.1016/j.biotechadv.2021.107725] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 01/15/2021] [Accepted: 02/25/2021] [Indexed: 12/21/2022]
Abstract
As fungus-like protists, thraustochytrids have been increasingly studied for their faster growth rates and high lipid content. In the 1990s, thraustochytrids were used as docosahexaenoic acid (DHA) producers for the first time. Thraustochytrids genera, such as Thraustochytrium, Schizochytrium, and Aurantiochytrium have been developed and patented as industrial strains for DHA production. The high DHA yield is attributed to its unique and efficient polyketide-like synthase (PKS) pathway. Moreover, thraustochytrids possess a completed mevalonate (MVA) pathway, so it can be used as host for terpenoid production. In order to improve strain performance, the metabolic engineering strategies have been applied to promote or disrupt intracellular metabolic pathways, such as genetic engineering and addition of chemical activators. However, it is difficult to realize industrialization only by improving strain performance. Various operation strategies were developed to enlarge the production quantities from the laboratory-scale, including two-stage cultivation strategies, scale-up technologies and bioreactor design. Moreover, an economical and effective downstream process is also an important consideration for the industrial application of thraustochytrids. Downstream costs accounts for 20-60% of the overall process costs, which represents an attractive target for increasing the cost-competitiveness of thraustochytrids, including how to improve the efficiency of lipid extraction and the further application of biomass residues. This review aims to overview the whole lipid biotechnology of thraustochytrids to provide the background information for researchers.
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Affiliation(s)
- Fei Du
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, 2 Xuelin Road, Qixia District, Nanjing, People's Republic of China
| | - Yu-Zhou Wang
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, 2 Xuelin Road, Qixia District, Nanjing, People's Republic of China
| | - Ying-Shuang Xu
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, 2 Xuelin Road, Qixia District, Nanjing, People's Republic of China
| | - Tian-Qiong Shi
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, 2 Xuelin Road, Qixia District, Nanjing, People's Republic of China
| | - Wen-Zheng Liu
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, 2 Xuelin Road, Qixia District, Nanjing, People's Republic of China
| | - Xiao-Man Sun
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, 2 Xuelin Road, Qixia District, Nanjing, People's Republic of China.
| | - He Huang
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, 2 Xuelin Road, Qixia District, Nanjing, People's Republic of China; College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing, People's Republic of China
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Oslan SNH, Tan JS, Abbasiliasi S, Ziad Sulaiman A, Saad MZ, Halim M, Ariff AB. Integrated Stirred-Tank Bioreactor with Internal Adsorption for the Removal of Ammonium to Enhance the Cultivation Performance of gdhA Derivative Pasteurella multocida B:2. Microorganisms 2020; 8:E1654. [PMID: 33114463 PMCID: PMC7693258 DOI: 10.3390/microorganisms8111654] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 10/06/2020] [Accepted: 10/06/2020] [Indexed: 12/03/2022] Open
Abstract
Growth of mutant gdhA Pasteurella multocida B:2 was inhibited by the accumulation of a by-product, namely ammonium in the culture medium during fermentation. The removal of this by-product during the cultivation of mutant gdhA P. multocida B:2 in a 2 L stirred-tank bioreactor integrated with an internal column using cation-exchange adsorption resin for the improvement of cell viability was studied. Different types of bioreactor system (dispersed and internal) with resins were successfully used for ammonium removal at different agitation speeds. The cultivation in a bioreactor integrated with an internal column demonstrated a significant improvement in growth performance of mutant gdhA P. multocida B:2 (1.05 × 1011 cfu/mL), which was 1.6-fold and 8.4-fold as compared to cultivation with dispersed resin (7.2 × 1010 cfu/mL) and cultivation without resin (1.25 × 1010 cfu/mL), respectively. The accumulation of ammonium in culture medium without resin (801 mg/L) was 1.24-fold and 1.37-fold higher than culture with dispersed resin (642.50 mg/L) and culture in the bioreactor integrated with internal adsorption (586.50 mg/L), respectively. Results from this study demonstrated that cultivation in a bioreactor integrated with the internal adsorption column in order to remove ammonium could reduce the inhibitory effect of this by-product and improve the growth performance of mutant gdhA P. multocida B:2.
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Affiliation(s)
- Siti Nur Hazwani Oslan
- Bioprocessing and Biomanufacturing Research Centre, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang, Selangor 43400, Malaysia;
- Faculty of Bioengineering and Technology, University Malaysia Kelantan, Jeli Campus, Jeli, Kelantan 17600, Malaysia;
| | - Joo Shun Tan
- Bioprocess Technology, School of Industrial Technology, Universiti Sains Malaysia, Penang 11800, Malaysia;
| | - Sahar Abbasiliasi
- Halal Products Research Institute, Universiti Putra Malaysia, Serdang, Selangor 43400, Malaysia;
| | - Ahmad Ziad Sulaiman
- Faculty of Bioengineering and Technology, University Malaysia Kelantan, Jeli Campus, Jeli, Kelantan 17600, Malaysia;
| | - Mohd Zamri Saad
- Research Centre for Ruminant Diseases, Faculty of Veterinary Medicine, Universiti Putra Malaysia, Serdang, Selangor 43400, Malaysia;
| | - Murni Halim
- Department of Bioprocess Technology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang, Selangor 43400, Malaysia;
| | - Arbakariya B. Ariff
- Bioprocessing and Biomanufacturing Research Centre, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang, Selangor 43400, Malaysia;
- Department of Bioprocess Technology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang, Selangor 43400, Malaysia;
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Dai K, Zhao J, Cheng Y, Tian C, Zhang C, Chen M. Inulin as a Promising Alternative Feedstock for Docosahexaenoic Acid Production by
Schizochytrium
sp. ATCC 20888. EUR J LIPID SCI TECH 2020. [DOI: 10.1002/ejlt.202000079] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Kexin Dai
- School of Biological Engineering Dalian Polytechnic University Dalian 116034 China
| | - Jing Zhao
- College of Life Science Dalian Minzu University Dalian 116600 China
| | - Yan Cheng
- School of Biological Engineering Dalian Polytechnic University Dalian 116034 China
| | - Chang Tian
- School of Biological Engineering Dalian Polytechnic University Dalian 116034 China
| | - Chunzhi Zhang
- School of Biological Engineering Dalian Polytechnic University Dalian 116034 China
| | - Ming Chen
- School of Biological Engineering Dalian Polytechnic University Dalian 116034 China
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16
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Guo DS, Tong LL, Ji XJ, Ren LJ, Ding QQ. Development of a Strategy to Improve the Stability of Culture Environment for Docosahexaenoic Acid Fermentation by Schizochytrium sp. Appl Biochem Biotechnol 2020; 192:881-894. [DOI: 10.1007/s12010-020-03298-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 03/12/2020] [Indexed: 11/30/2022]
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17
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Chen CY, Lee MH, Dong CD, Leong YK, Chang JS. Enhanced production of microalgal lipids using a heterotrophic marine microalga Thraustochytrium sp. BM2. Biochem Eng J 2020. [DOI: 10.1016/j.bej.2019.107429] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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18
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Lipid and DHA-production in Aurantiochytrium sp. - Responses to nitrogen starvation and oxygen limitation revealed by analyses of production kinetics and global transcriptomes. Sci Rep 2019; 9:19470. [PMID: 31857635 PMCID: PMC6923395 DOI: 10.1038/s41598-019-55902-4] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 12/04/2019] [Indexed: 01/30/2023] Open
Abstract
Thraustochytrids of the genera Schizochytrium and Aurantiochytrium accumulate oils rich in the essential, marine n3 fatty acid docosahexaenoic acid (DHA). DHA production in Aurantiochytrium sp T66 was studied with the aim to provide more knowledge about factors that affect the DHA-productivities and the contributions of the two enzyme systems used for fatty acid synthesis in thraustochytrids, fatty acid synthetase (FAS) and PUFA-synthase. Fermentations with nitrogen starvation, which is well-known to initiate lipid accumulation in oleaginous organisms, were compared to fermentations with nitrogen in excess, obtained by oxygen limitation. The specific productivities of fatty acids originating from FAS were considerably higher under nitrogen starvation than with nitrogen in excess, while the specific productivities of DHA were the same at both conditions. Global transcriptome analysis showed significant up-regulation of FAS under N-deficient conditions, while the PUFA-synthase genes were only marginally upregulated. Neither of them was upregulated under O2-limitation where nitrogen was in excess, suggesting that N-starvation mainly affects the FAS and may be less important for the PUFA-synthase. The transcriptome analysis also revealed responses likely to be related to the generation of reducing power (NADPH) for fatty acid synthesis.
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19
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Bernaerts TM, Gheysen L, Foubert I, Hendrickx ME, Van Loey AM. The potential of microalgae and their biopolymers as structuring ingredients in food: A review. Biotechnol Adv 2019; 37:107419. [DOI: 10.1016/j.biotechadv.2019.107419] [Citation(s) in RCA: 88] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 07/15/2019] [Accepted: 07/16/2019] [Indexed: 12/11/2022]
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20
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Boosting productivity of heterotrophic microalgae by efficient control of the oxygen transfer coefficient using a microbubble sparger. ALGAL RES 2019. [DOI: 10.1016/j.algal.2019.101474] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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21
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Production of High-Value Polyunsaturated Fatty Acids Using Microbial Cultures. Methods Mol Biol 2019. [PMID: 31148133 DOI: 10.1007/978-1-4939-9484-7_15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
Microbes can produce not only commodity fatty acids, such as palmitic acid (16:0) and stearic acid (18:0), but also high-value fatty acids (essential fatty acids). Most high value fatty acids belong to long chain polyunsaturated fatty acids (PUFA), such as omega-3 fatty acids (e.g., eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)) and omega-6 fatty acids (e.g., arachidonic acid (ARA) and γ-linolenic acid (GLA)). EPA (20:5n-3) is a 20-carbon fatty acid with five double bonds, and the first double bond is in the n-3 position. DHA (22:6n-3) is a 22-carbon fatty acid with 6 double bonds and the first double bond is also in the n-3 position. Both EPA and DHA play an essential role in cardiovascular health including prevention of atherosclerotic disease development (Zehr and Walker, Prostaglandins Other Lipid Mediat 134:131-140, 2018). ARA (20:4n-6) is a 20-carbon fatty acid with four double bonds, and the first double bond is in the n-6 position. GLA (18:3n-6) is an 18-carbon fatty acid with three double bonds, and the first double bond is in the n-6 position. ARA and GLA have multiple biological effects, such as lowering blood cholesterol, and lowering cardiovascular mortality (Poli and Visioli, Eur J Lipid Sci Technol 117(11):1847-1852, 2015). This chapter provides details on microbial production of EAP, DHA, ARA, and GLA.
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22
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Ramos-Vega A, Rosales-Mendoza S, Bañuelos-Hernández B, Angulo C. Prospects on the Use of Schizochytrium sp. to Develop Oral Vaccines. Front Microbiol 2018; 9:2506. [PMID: 30410471 PMCID: PMC6209683 DOI: 10.3389/fmicb.2018.02506] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 10/02/2018] [Indexed: 12/12/2022] Open
Abstract
Although oral subunit vaccines are highly relevant in the fight against widespread diseases, their high cost, safety and proper immunogenicity are attributes that have yet to be addressed in many cases and thus these limitations should be considered in the development of new oral vaccines. Prominent examples of new platforms proposed to address these limitations are plant cells and microalgae. Schizochytrium sp. constitutes an attractive expression host for vaccine production because of its high biosynthetic capacity, fast growth in low cost culture media, and the availability of processes for industrial scale production. In addition, whole Schizochytrium sp. cells may serve as delivery vectors; especially for oral vaccines since Schizochytrium sp. is safe for oral consumption, produces immunomodulatory compounds, and may provide bioencapsulation to the antigen, thus increasing its bioavailability. Remarkably, Schizochytrium sp. was recently used for the production of a highly immunoprotective influenza vaccine. Moreover, an efficient method for transient expression of antigens based on viral vectors and Schizochytrium sp. as host has been recently developed. In this review, the potential of Schizochytrium sp. in vaccinology is placed in perspective, with emphasis on its use as an attractive oral vaccination vehicle.
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Affiliation(s)
- Abel Ramos-Vega
- Grupo de Inmunología and Vacunología, Centro de Investigaciones Biológicas del Noroeste, La Paz, Mexico
| | - Sergio Rosales-Mendoza
- Laboratorio de Biofarmacéuticos Recombinantes, Facultad de Ciencias Químicas, Universidad Autónoma de San Luis Potosí, San Luis Potosí, Mexico.,Sección de Biotecnología, Centro de Investigación en Ciencias de la Salud y Biomedicina, Universidad Autónoma de San Luis Potosí, San Luis Potosí, Mexico
| | | | - Carlos Angulo
- Grupo de Inmunología and Vacunología, Centro de Investigaciones Biológicas del Noroeste, La Paz, Mexico
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23
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Zhang S, He Y, Sen B, Chen X, Xie Y, Keasling JD, Wang G. Alleviation of reactive oxygen species enhances PUFA accumulation in Schizochytrium sp. through regulating genes involved in lipid metabolism. Metab Eng Commun 2018; 6:39-48. [PMID: 29896446 PMCID: PMC5994804 DOI: 10.1016/j.meteno.2018.03.002] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Accepted: 03/26/2018] [Indexed: 12/21/2022] Open
Abstract
The unicellular heterotrophic thraustochytrids are attractive candidates for commercial polyunsaturated fatty acids (PUFA) production. However, the reactive oxygen species (ROS) generated in their aerobic fermentation process often limits their PUFA titer. Yet, the specific mechanisms of ROS involvement in the crosstalk between oxidative stress and intracellular lipid synthesis remain poorly described. Metabolic engineering to improve the PUFA yield in thraustochytrids without compromising growth is an important aspect of economic feasibility. To fill this gap, we overexpressed the antioxidative gene superoxide dismutase (SOD1) by integrating it into the genome of thraustochytrid Schizochytrium sp. PKU#Mn4 using a novel genetic transformation system. This study reports the ROS alleviation, enhanced PUFA production and transcriptome changes resulting from the SOD1 overexpression. SOD1 activity in the recombinant improved by 5.2-71.6% along with 7.8-38.5% decline in ROS during the fermentation process. Interestingly, the total antioxidant capacity in the recombinant remained higher than wild-type and above zero in the entire process. Although lipid profile was similar to that of wild-type, the concentrations of major fatty acids in the recombinant were significantly (p ≤ 0.05) higher. The PUFA titer increased up to 1232 ± 41 mg/L, which was 32.9% higher (p ≤ 0.001) than the wild type. Transcriptome analysis revealed strong downregulation of genes potentially involved in β-oxidation of fatty acids in peroxisome and upregulation of genes catalyzing lipid biosynthesis. Our results enrich the knowledge on stress-induced PUFA biosynthesis and the putative role of ROS in the regulation of lipid metabolism in oleaginous thraustochytrids. This study provides a new and alternate strategy for cost-effective industrial fermentation of PUFA.
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Affiliation(s)
- Sai Zhang
- Center for Marine Environmental Ecology, School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Yaodong He
- Center for Marine Environmental Ecology, School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Biswarup Sen
- Center for Marine Environmental Ecology, School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Xiaohong Chen
- State Key Laboratory of Systems Engines, Tianjin University, Tianjin 300072, China
| | - Yunxuan Xie
- Center for Marine Environmental Ecology, School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Jay D. Keasling
- Berkeley Center for Synthetic Biology, University of California, Berkeley, CA 94720-3224, USA
| | - Guangyi Wang
- Center for Marine Environmental Ecology, School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
- State Key Laboratory of Systems Engines, Tianjin University, Tianjin 300072, China
- Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, China
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24
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Mathematical modeling of fed-batch fermentation of Schizochytrium sp. FJU-512 growth and DHA production using a shift control strategy. 3 Biotech 2018. [PMID: 29527449 DOI: 10.1007/s13205-018-1187-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022] Open
Abstract
To obtain high-cell-density cultures of Schizochytrium sp. FJU-512 for DHA production, two stages of fermentation strategy were used and carbon/nitrogen ratio, DO and temperature were controlled at different levels. The final dry cell weight, total lipid production and DHA yield in 15 l bioreactor reached 103.9, 37.2 and 16.0 g/l, respectively. For the further study of microbial growth and DHA production dynamics, we established a set of kinetic models for the fed-batch production of DHA by Schizochytrium sp. FJU-512 in 15 and 100 l fermenters and a compensatory parameter n was integrated into the model in order to find the optimal mathematical equations. A modified Logistic model was proposed to fit the cell growth data and the following kinetic parameters were obtained: µm = 0.0525/h, Xm = 100 g/l and n = 4.1717 for the 15 l bioreactor, as well as µm = 0.0382/h, Xm = 107.4371 g/l and n = 10 for the 100 l bioreactor. The Luedeking-Piret equations were utilized to model DHA production, yielding values of α = 0.0648 g/g and β = 0.0014 g/g/h for the 15 l bioreactor, while the values of α and β obtained for the 100 l fermentation were 0.0209 g/g and 0.0030 g/g/h. The predicted results compared with experimental data showed that the established models had a good fitting precision and were able to exactly depict the dynamic features of the DHA production process.
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25
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Sun XM, Geng LJ, Ren LJ, Ji XJ, Hao N, Chen KQ, Huang H. Influence of oxygen on the biosynthesis of polyunsaturated fatty acids in microalgae. BIORESOURCE TECHNOLOGY 2018; 250:868-876. [PMID: 29174352 DOI: 10.1016/j.biortech.2017.11.005] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 11/03/2017] [Accepted: 11/05/2017] [Indexed: 05/02/2023]
Abstract
As one of the most important environmental factors, oxygen is particularly important for synthesis of n-3 polyunsaturated fatty acids (n-3 PUFA) in microalgae. In general, a higher oxygen supply is beneficial for cell growth but obstructs PUFA synthesis. The generation of reactive oxygen species (ROS) under aerobic conditions, which leads to the peroxidation of lipids and especially PUFA, is an inevitable aspect of life, but is often ignored in fermentation processes. Irritability, microalgal cells are able to activate a number of anti-oxidative defenses, and the lipid profile of many species is reported to be altered under oxidative stress. In this review, the effects of oxygen on the PUFA synthesis, sources of oxidative damage, and anti-oxidative defense systems of microalgae were summarized and discussed. Moreover, this review summarizes the published reports on microalgal biotechnology involving direct/indirect oxygen regulation and new bioreactor designs that enable the improved production of PUFA.
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Affiliation(s)
- Xiao-Man Sun
- Jiangsu National Synergetic Innovation Center for Advanced Materials, State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, School of Pharmacy, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing 211816, People's Republic of China
| | - Ling-Jun Geng
- Jiangsu National Synergetic Innovation Center for Advanced Materials, State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, School of Pharmacy, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing 211816, People's Republic of China
| | - Lu-Jing Ren
- Jiangsu National Synergetic Innovation Center for Advanced Materials, State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, School of Pharmacy, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing 211816, People's Republic of China.
| | - Xiao-Jun Ji
- Jiangsu National Synergetic Innovation Center for Advanced Materials, State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, School of Pharmacy, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing 211816, People's Republic of China
| | - Ning Hao
- Jiangsu National Synergetic Innovation Center for Advanced Materials, State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, School of Pharmacy, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing 211816, People's Republic of China
| | - Ke-Quan Chen
- Jiangsu National Synergetic Innovation Center for Advanced Materials, State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, School of Pharmacy, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing 211816, People's Republic of China
| | - He Huang
- Jiangsu National Synergetic Innovation Center for Advanced Materials, State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, School of Pharmacy, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing 211816, People's Republic of China
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26
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Enhancement of Schizochytrium DHA synthesis by plasma mutagenesis aided with malonic acid and zeocin screening. Appl Microbiol Biotechnol 2018; 102:2351-2361. [DOI: 10.1007/s00253-018-8756-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 12/28/2017] [Accepted: 12/30/2017] [Indexed: 12/28/2022]
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27
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Bi ZQ, Ren LJ, Hu XC, Sun XM, Zhu SY, Ji XJ, Huang H. Transcriptome and gene expression analysis of docosahexaenoic acid producer Schizochytrium sp. under different oxygen supply conditions. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:249. [PMID: 30245741 PMCID: PMC6142690 DOI: 10.1186/s13068-018-1250-5] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 09/06/2018] [Indexed: 05/09/2023]
Abstract
BACKGROUND Schizochytrium sp. is a promising strain for the production of docosahexaenoic acid (DHA)-rich oil and biodiesel, and has been widely used in the food additive and bioenergy industries. Oxygen is a particularly important environmental factor for cell growth and DHA synthesis. In general, higher oxygen supply favors lipid accumulation, but could lead to a reduction of the DHA percentage in total fatty acids in Schizochytrium sp. To tackle this problem, it is essential to understand the mechanisms regulating the response of Schizochytrium sp. to oxygen. In this study, we aimed to explore the acclimatization of this DHA producer to different oxygen supply conditions by examining the transcriptome changes. RESULTS Two different fermentation processes, namely normal oxygen supply condition (shift agitation speeds from 400 rpm to 300 rpm) and high oxygen supply condition (constant agitation speeds: 400 rpm), were designed to study how the fermentation characteristics of Schizochytrium sp. HX-308 were affected by different oxygen supply conditions. The results indicated that high oxygen supply condition resulted in 49% and 37.5% improvement in the maximum cell dry weight (CDW) and total lipid concentration, respectively. However, the DHA percentage in total fatty acids decreased to 35%, which was 31.4% lower than that produced by normal oxygen supply condition. Moreover, transcriptome analysis was performed to explore the effect of the oxygen supply condition on genetic expression and metabolism. The results showed that glycolysis and pentose phosphate pathway metabolism-associated genes (hexokinase, phosphofructokinase, fructose-bisphosphate aldolase, glucose-6-phosphate dehydrogenase, and 6-phosphogluconate dehydrogenase) were substantially upregulated in response to high oxygen supply, resulting in more NADPH was available for Schizochytrium. Specially, high oxygen supply condition also led to genes (Δ6 desaturase, Δ12 desaturase, FAS, ORFA, ORFB, and ORFC) involved in fatty acid biosynthesis upregulation. In addition, a transcriptional upregulation of catalase (CAT) became apparent under high oxygen supply condition, while superoxide dismutase (SOD) and ascorbate peroxidase (APX) were found to be down-regulated. CONCLUSIONS This study is the first to investigate the differences of gene expression at different levels of oxygen availability in the DHA producer Schizochytrium. The results of transcriptome analyses indicated that high oxygen supply condition resulting in more NADPH and acetyl-CoA production for cell growth and lipid synthesis in Schizochytrium. Δ12 desaturase and ORFC showed higher expression levels at high oxygen supply condition, which might be the key regulators for enhancing fatty acid biosynthesis in the future. These results enrich the current knowledge regarding genetic expression and provide important information to enhance DHA production in Schizochytrium sp.
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Affiliation(s)
- Zhi-Qian Bi
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing, 211816 People’s Republic of China
| | - Lu-Jing Ren
- Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), No. 30 South Puzhu Road, Nanjing, 211816 People’s Republic of China
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing, 211816 People’s Republic of China
| | - Xue-Chao Hu
- Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), No. 30 South Puzhu Road, Nanjing, 211816 People’s Republic of China
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing, 211816 People’s Republic of China
| | - Xiao-Man Sun
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing, 211816 People’s Republic of China
| | - Si-Yu Zhu
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing, 211816 People’s Republic of China
| | - Xiao-Jun Ji
- Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), No. 30 South Puzhu Road, Nanjing, 211816 People’s Republic of China
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing, 211816 People’s Republic of China
| | - He Huang
- Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), No. 30 South Puzhu Road, Nanjing, 211816 People’s Republic of China
- School of Pharmaceutical Sciences, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing, 211816 People’s Republic of China
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, No. 5 Xinmofan Road, Nanjing, 210009 People’s Republic of China
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28
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Guo DS, Ji XJ, Ren LJ, Li GL, Huang H. Improving docosahexaenoic acid production by Schizochytrium
sp. using a newly designed high-oxygen-supply bioreactor. AIChE J 2017. [DOI: 10.1002/aic.15783] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Dong-Sheng Guo
- College of Biotechnology and Pharmaceutical Engineering; Nanjing Tech University; No. 30 South Puzhu Road Nanjing 211816 P.R. China
| | - Xiao-Jun Ji
- College of Biotechnology and Pharmaceutical Engineering; Nanjing Tech University; No. 30 South Puzhu Road Nanjing 211816 P.R. China
- Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM); No. 5 Xinmofan Road Nanjing 210009 P.R. China
| | - Lu-Jing Ren
- College of Biotechnology and Pharmaceutical Engineering; Nanjing Tech University; No. 30 South Puzhu Road Nanjing 211816 P.R. China
- Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM); No. 5 Xinmofan Road Nanjing 210009 P.R. China
| | - Gan-Lu Li
- College of Biotechnology and Pharmaceutical Engineering; Nanjing Tech University; No. 30 South Puzhu Road Nanjing 211816 P.R. China
| | - He Huang
- School of Pharmaceutical Sciences; Nanjing Tech University; No. 30 South Puzhu Road Nanjing 211816 P.R. China
- State Key Laboratory of Materials-Oriented Chemical Engineering; Nanjing Tech University; No. 5 Xinmofan Road Nanjing 210009 P.R. China
- Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM); No. 5 Xinmofan Road Nanjing 210009 P.R. China
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Su L, Shen Y, Gao T, Luo J, Wang M. Improvement of AD Biosynthesis Response to Enhanced Oxygen Transfer by Oxygen Vectors in Mycobacterium neoaurum TCCC 11979. Appl Biochem Biotechnol 2017; 182:1564-1574. [DOI: 10.1007/s12010-017-2418-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 01/17/2017] [Indexed: 12/01/2022]
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Guo DS, Ji XJ, Ren LJ, Li GL, Yin FW, Huang H. Development of a real-time bioprocess monitoring method for docosahexaenoic acid production by Schizochytrium sp. BIORESOURCE TECHNOLOGY 2016; 216:422-7. [PMID: 27262097 DOI: 10.1016/j.biortech.2016.05.044] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 05/13/2016] [Accepted: 05/15/2016] [Indexed: 05/21/2023]
Abstract
Oxygen uptake rate (OUR) and respiratory quotient (RQ) are key respiratory parameters for docosahexaenoic acid (DHA) production by Schizochytrium sp. HX-308 under dissolved oxygen limited conditions. To investigate the relationship of OUR and RQ with culture status, three independent cultures with different aeration rates were performed in a 50L bioreactor. OUR was found to be positively correlated with the aeration rate, which reflected the oxygen supply level in each culture. The highest biomass, reaching 124.5g/L, was achieved under the highest OUR. DHA content was found to be highly correlated with the RQ value, and the highest DHA content (44.85% in total fatty acids, w/w) was achieved in the highest RQ level, which implies that the polyketide synthase pathway was more active. OUR and RQ, which reflect the physiological state of microorganisms, are suggested as synergistic real-time bioprocess monitoring parameters for DHA fermentation.
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Affiliation(s)
- Dong-Sheng Guo
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing 211816, People's Republic of China
| | - Xiao-Jun Ji
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing 211816, People's Republic of China; Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), No. 5 Xinmofan Road, Nanjing 210009, People's Republic of China
| | - Lu-Jing Ren
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing 211816, People's Republic of China; Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), No. 5 Xinmofan Road, Nanjing 210009, People's Republic of China
| | - Gan-Lu Li
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing 211816, People's Republic of China
| | - Feng-Wei Yin
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing 211816, People's Republic of China
| | - He Huang
- School of Pharmaceutical Sciences, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing 211816, People's Republic of China; State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, No. 5 Xinmofan Road, Nanjing 210009, People's Republic of China; Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), No. 5 Xinmofan Road, Nanjing 210009, People's Republic of China.
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Silva DDV, Dussán KJ, Hernández V, Silva SSD, Cardona CA, Felipe MDGDA. Effect of volumetric oxygen transfer coefficient (k L a) on ethanol production performance by Scheffersomyces stipitis on hemicellulosic sugarcane bagasse hydrolysate. Biochem Eng J 2016. [DOI: 10.1016/j.bej.2016.04.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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CFD investigation of Schizochytrium sp. impeller configurations on cell growth and docosahexaenoic acid synthesis. Bioprocess Biosyst Eng 2016; 39:1297-304. [DOI: 10.1007/s00449-016-1608-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2016] [Accepted: 04/09/2016] [Indexed: 10/21/2022]
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Aasen IM, Ertesvåg H, Heggeset TMB, Liu B, Brautaset T, Vadstein O, Ellingsen TE. Thraustochytrids as production organisms for docosahexaenoic acid (DHA), squalene, and carotenoids. Appl Microbiol Biotechnol 2016; 100:4309-21. [DOI: 10.1007/s00253-016-7498-4] [Citation(s) in RCA: 107] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2016] [Revised: 03/19/2016] [Accepted: 03/22/2016] [Indexed: 01/09/2023]
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Running JA, Bansal K. Oxygen transfer rates in shaken culture vessels from Fernbach flasks to microtiter plates. Biotechnol Bioeng 2016; 113:1729-35. [DOI: 10.1002/bit.25938] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Revised: 01/05/2016] [Accepted: 01/22/2016] [Indexed: 11/09/2022]
Affiliation(s)
- Jeffrey A. Running
- Department of Bioengineering and Bioprocessing R&D; Dow AgroSciences; Indianapolis Indiana
| | - Karan Bansal
- Department of Bioengineering and Bioprocessing R&D; Dow AgroSciences; Indianapolis Indiana
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Ling X, Guo J, Liu X, Zhang X, Wang N, Lu Y, Ng IS. Impact of carbon and nitrogen feeding strategy on high production of biomass and docosahexaenoic acid (DHA) by Schizochytrium sp. LU310. BIORESOURCE TECHNOLOGY 2015; 184:139-147. [PMID: 25451778 DOI: 10.1016/j.biortech.2014.09.130] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2014] [Revised: 09/23/2014] [Accepted: 09/25/2014] [Indexed: 05/22/2023]
Abstract
A new isolated Schizochytrium sp. LU310 from the mangrove forest of Wenzhou, China, was found as a high producing microalga of docosahexaenoic acid (DHA). In this study, the significant improvements for DHA fermentation by the batch mode in the baffled flasks (i.e. higher oxygen supply) were achieved. By applied the nitrogen-feeding strategy in 1000 mL baffled flasks, the biomass, DHA concentration and DHA productivity were increased by 110.4%, 117.9% and 110.4%, respectively. Moreover, DHA concentration of 21.06 g/L was obtained by feeding 15 g/L of glucose intermittently, which was an increase of 41.25% over that of the batch mode. Finally, an innovative strategy was carried out by intermittent feeding carbon and simultaneously feeding nitrogen. The maximum DHA concentration and DHA productivity in the fed-batch cultivation reached to 24.74 g/L and 241.5 mg/L/h, respectively.
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Affiliation(s)
- Xueping Ling
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, PR China
| | - Jing Guo
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, PR China
| | - Xiaoting Liu
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, PR China
| | - Xia Zhang
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, PR China
| | - Nan Wang
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, PR China
| | - Yinghua Lu
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, PR China
| | - I-Son Ng
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, PR China; Department of Chemical Engineering, National Cheng Kung University, Tainan 70101, Taiwan.
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Bai Y, Zhou PP, Fan P, Zhu YM, Tong Y, Wang HB, Yu LJ. Four-stage dissolved oxygen strategy based on multi-scale analysis for improving spinosad yield by Saccharopolyspora spinosa ATCC49460. Microb Biotechnol 2015; 8:561-8. [PMID: 25808914 PMCID: PMC4408188 DOI: 10.1111/1751-7915.12264] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Revised: 11/24/2014] [Accepted: 12/26/2014] [Indexed: 11/29/2022] Open
Abstract
Dissolved oxygen (DO) is an important influencing factor in the process of aerobic microbial fermentation. Spinosad is an aerobic microbial-derived secondary metabolite. In our study, spinosad was used as an example to establish a DO strategy by multi-scale analysis, which included a reactor, cell and gene scales. We changed DO conditions that are related to the characteristics of cell metabolism (glucose consumption rate, biomass accumulation and spinosad production). Consequently, cell growth was promoted by maintaining DO at 40% in the first 24 h and subsequently increasing DO to 50% in 24 h to 96 h. In an in-depth analysis of the key enzyme genes (gtt, spn A, spn K and spn O), expression of spinosad and specific Adenosine Triphosphate (ATP), the spinosad yield was increased by regulating DO to 30% within 96 h to 192 h and then changing it to 25% in 192 h to 240 h. Under the four-phase DO strategy, spinosad yield increased by 652.1%, 326.1%, 546.8%, and 781.4% compared with the yield obtained under constant DO control at 50%, 40%, 30%, and 20% respectively. The proposed method provides a novel way to develop a precise DO strategy for fermentation.
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Affiliation(s)
- Yun Bai
- Institute of Resource Biology and Biotechnology, Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China; Key Laboratory of Molecular Biophysics Ministry of Education, Huazhong University of Science and Technology, Wuhan, 430074, China
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Trujillo-de Santiago G, Rojas-de Gante C, García-Lara S, Ballescá-Estrada A, Alvarez MM. Studying mixing in Non-Newtonian blue maize flour suspensions using color analysis. PLoS One 2014; 9:e112954. [PMID: 25401332 PMCID: PMC4234479 DOI: 10.1371/journal.pone.0112954] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Accepted: 10/22/2014] [Indexed: 11/19/2022] Open
Abstract
Background Non-Newtonian fluids occur in many relevant flow and mixing scenarios at the lab and industrial scale. The addition of acid or basic solutions to a non-Newtonian fluid is not an infrequent operation, particularly in Biotechnology applications where the pH of Non-Newtonian culture broths is usually regulated using this strategy. Methodology and Findings We conducted mixing experiments in agitated vessels using Non-Newtonian blue maize flour suspensions. Acid or basic pulses were injected to reveal mixing patterns and flow structures and to follow their time evolution. No foreign pH indicator was used as blue maize flours naturally contain anthocyanins that act as a native, wide spectrum, pH indicator. We describe a novel method to quantitate mixedness and mixing evolution through Dynamic Color Analysis (DCA) in this system. Color readings corresponding to different times and locations within the mixing vessel were taken with a digital camera (or a colorimeter) and translated to the CIELab scale of colors. We use distances in the Lab space, a 3D color space, between a particular mixing state and the final mixing point to characterize segregation/mixing in the system. Conclusion and Relevance Blue maize suspensions represent an adequate and flexible model to study mixing (and fluid mechanics in general) in Non-Newtonian suspensions using acid/base tracer injections. Simple strategies based on the evaluation of color distances in the CIELab space (or other scales such as HSB) can be adapted to characterize mixedness and mixing evolution in experiments using blue maize suspensions.
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Affiliation(s)
- Grissel Trujillo-de Santiago
- Centro de Biotecnología-FEMSA, Tecnológico de Monterrey, Monterrey, Nuevo León, México
- Centro de Investigación y Desarrollo de Proteínas (CIDPRO), Tecnológico de Monterrey, Monterrey, Nuevo León, México
| | - Cecilia Rojas-de Gante
- Departamento de Ingeniería en Biotecnología, Tecnológico de Monterrey, Tlalpan, Distrito Federal, México
| | - Silverio García-Lara
- Centro de Biotecnología-FEMSA, Tecnológico de Monterrey, Monterrey, Nuevo León, México
| | | | - Mario Moisés Alvarez
- Centro de Biotecnología-FEMSA, Tecnológico de Monterrey, Monterrey, Nuevo León, México
- * E-mail:
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