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Lei Y, Wang X, Sun S, He B, Sun W, Wang K, Chen Z, Guo Z, Li Z. A review of lipid accumulation by oleaginous yeasts: Culture mode. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 919:170385. [PMID: 38364585 DOI: 10.1016/j.scitotenv.2024.170385] [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: 11/10/2023] [Revised: 01/05/2024] [Accepted: 01/21/2024] [Indexed: 02/18/2024]
Abstract
Microbial lipids have attracted considerable interest owing to their favorable environmental sustainability benefits. In laboratory-scale studies, the factors impacting lipid production in oleaginous yeasts, including culture conditions, nutrients, and low-cost substrates, have been extensively studied. However, there were several different modes of microbial lipid cultivation (batch culture, fed-batch culture, continuous culture, and other novel culture modes), making it difficult to comprehensively analyze impacting factors under different cultivation modes on a laboratory scale. And only few cases of microbial lipid production have been conducted at the pilot scale, which requires more technological reliability assessments and environmental benefit evaluations. Thus, this study summarized the different culture modes and cases of scale-up processes, highlighting the role of the nutrient element ratio in regulating culture mode selection and lipid accumulation. The cost distribution and environmental benefits of microbial lipid production by oleaginous yeasts were also investigated. Our results suggested that the continuous culture mode was recommended for the scale-up process because of its stable lipid accumulation. More importantly, exploring the continuous culture mode integrated with other efficient culture modes remained to be further investigated. In research on scale-up processes, low-cost substrate (organic waste) application and optimization of reactor operational parameters were key to increasing environmental benefits and reducing costs.
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Affiliation(s)
- Yuxin Lei
- School of Energy and Environmental Engineering, Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, University of Science and Technology Beijing, Xueyuan Road No.30, Haidian District, Beijing 100083, PR China
| | - Xuemei Wang
- School of Energy and Environmental Engineering, Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, University of Science and Technology Beijing, Xueyuan Road No.30, Haidian District, Beijing 100083, PR China.
| | - Shushuang Sun
- School of Energy and Environmental Engineering, Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, University of Science and Technology Beijing, Xueyuan Road No.30, Haidian District, Beijing 100083, PR China.
| | - Bingyang He
- School of Energy and Environmental Engineering, Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, University of Science and Technology Beijing, Xueyuan Road No.30, Haidian District, Beijing 100083, PR China
| | - Wenjin Sun
- School of Energy and Environmental Engineering, Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, University of Science and Technology Beijing, Xueyuan Road No.30, Haidian District, Beijing 100083, PR China
| | - Kexin Wang
- School of Energy and Environmental Engineering, Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, University of Science and Technology Beijing, Xueyuan Road No.30, Haidian District, Beijing 100083, PR China
| | - Zhengxian Chen
- School of Energy and Environmental Engineering, Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, University of Science and Technology Beijing, Xueyuan Road No.30, Haidian District, Beijing 100083, PR China
| | - Zhiling Guo
- School of Geography, Earth & Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom.
| | - Zifu Li
- School of Energy and Environmental Engineering, Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, University of Science and Technology Beijing, Xueyuan Road No.30, Haidian District, Beijing 100083, PR China.
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Oleaginous yeasts: Biodiversity and cultivation. FUNGAL BIOL REV 2023. [DOI: 10.1016/j.fbr.2022.11.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Ilmi M, Badrani A, Fauziyah A. Increasing lipid production from Zygosaccharomyces siamensis AP1 in molasses substrate using sequencing batch method. Prep Biochem Biotechnol 2023; 53:288-296. [PMID: 35670649 DOI: 10.1080/10826068.2022.2081859] [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: 10/18/2022]
Abstract
Yeasts are considered potential lipid producers to substitute oil-producing plants. Previous study succeeded in isolating Zygosaccharomyces siamensis AP1 from Indonesia which was able to accumulate 19% lipid. The strain, however, was not optimized for high cell density growth which is required for industry-level. In this study, efforts were made to increase cell density and lipid production of Z. siamensis AP1 using molasses as carbon source and implementing sequencing batch method. The yeast was grown in various combinations of carbon and nitrogen sources. The C:N ratio of the best substrate combination is then optimized. Afterwards, batch and sequencing batch methods were applied in fermentation with various concentrations (20-480 g/L) of molasses. The results show that lipid produced using molasses was slightly higher compared to using glucose, 0.21 g/L and 0.19 g/L respectively, with the same nitrogen source. Combination of molasses and ammonium sulfate with C:N ratio 70:1 gave the highest lipid (0.28 g/L). Sequencing batch able to increase cell density 2.4-fold compared to batch method. This study was the first to report that sequencing batch application with molasses as carbon source can increase lipid production from Z. siamensis. Further study to optimize medium composition for sequencing batch is suggested.
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Affiliation(s)
- Miftahul Ilmi
- Faculty of Biology, Universitas Gadjah Mada, Yogyakarta, Indonesia
| | - Anugrah Badrani
- Faculty of Biology, Universitas Gadjah Mada, Yogyakarta, Indonesia
| | - Annisa Fauziyah
- Faculty of Biology, Universitas Gadjah Mada, Yogyakarta, Indonesia
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Shen D, He X, Weng P, Liu Y, Wu Z. A review of yeast: High cell-density culture, molecular mechanisms of stress response and tolerance during fermentation. FEMS Yeast Res 2022; 22:6775076. [PMID: 36288242 DOI: 10.1093/femsyr/foac050] [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: 07/17/2022] [Revised: 09/21/2022] [Accepted: 10/22/2022] [Indexed: 01/07/2023] Open
Abstract
Yeast is widely used in the fermentation industry, and the major challenges in fermentation production system are high capital cost and low reaction rate. High cell-density culture is an effective method to increase the volumetric productivity of the fermentation process, thus making the fermentation process faster and more robust. During fermentation, yeast is subjected to various environmental stresses, including osmotic, ethanol, oxidation, and heat stress. To cope with these stresses, yeast cells need appropriate adaptive responses to acquire stress tolerances to prevent stress-induced cell damage. Since a single stressor can trigger multiple effects, both specific and nonspecific effects, general and specific stress responses are required to achieve comprehensive protection of cells. Since all these stresses disrupt protein structure, the upregulation of heat shock proteins and trehalose genes is induced when yeast cells are exposed to stress. A better understanding of the research status of yeast HCDC and its underlying response mechanism to various stresses during fermentation is essential for designing effective culture control strategies and improving the fermentation efficiency and stress resistance of yeast.
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Affiliation(s)
- Dongxu Shen
- Department of Food Science and Engineering, Ningbo University, Ningbo 315211, P.R. China
| | - Xiaoli He
- Department of Food Science and Engineering, Ningbo University, Ningbo 315211, P.R. China
| | - Peifang Weng
- Department of Food Science and Engineering, Ningbo University, Ningbo 315211, P.R. China
| | - Yanan Liu
- Department of Food Science and Engineering, Ningbo University, Ningbo 315211, P.R. China
| | - Zufang Wu
- Department of Food Science and Engineering, Ningbo University, Ningbo 315211, P.R. China
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Zhang XY, Li B, Huang BC, Wang FB, Zhang YQ, Zhao SG, Li M, Wang HY, Yu XJ, Liu XY, Jiang J, Wang ZP. Production, Biosynthesis, and Commercial Applications of Fatty Acids From Oleaginous Fungi. Front Nutr 2022; 9:873657. [PMID: 35694158 PMCID: PMC9176664 DOI: 10.3389/fnut.2022.873657] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 03/31/2022] [Indexed: 12/18/2022] Open
Abstract
Oleaginous fungi (including fungus-like protists) are attractive in lipid production due to their short growth cycle, large biomass and high yield of lipids. Some typical oleaginous fungi including Galactomyces geotrichum, Thraustochytrids, Mortierella isabellina, and Mucor circinelloides, have been well studied for the ability to accumulate fatty acids with commercial application. Here, we review recent progress toward fermentation, extraction, of fungal fatty acids. To reduce cost of the fatty acids, fatty acid productions from raw materials were also summarized. Then, the synthesis mechanism of fatty acids was introduced. We also review recent studies of the metabolic engineering strategies have been developed as efficient tools in oleaginous fungi to overcome the biochemical limit and to improve production efficiency of the special fatty acids. It also can be predictable that metabolic engineering can further enhance biosynthesis of fatty acids and change the storage mode of fatty acids.
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Affiliation(s)
- Xin-Yue Zhang
- School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao, China
| | - Bing Li
- School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao, China
| | - Bei-Chen Huang
- School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao, China
| | - Feng-Biao Wang
- School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao, China
| | - Yue-Qi Zhang
- School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao, China
| | - Shao-Geng Zhao
- School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao, China
| | - Min Li
- School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao, China
| | - Hai-Ying Wang
- Key Laboratory of Sustainable Development of Polar Fishery, Ministry of Agriculture and Rural Affairs, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
| | - Xin-Jun Yu
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
| | - Xiao-Yan Liu
- Jiangsu Key Laboratory for Biomass-Based Energy and Enzyme Technology, Huaiyin Normal University, Huaian, China
| | - Jing Jiang
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, Suzhou, China
| | - Zhi-Peng Wang
- School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao, China
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Abeln F, Chuck CJ. The history, state of the art and future prospects for oleaginous yeast research. Microb Cell Fact 2021; 20:221. [PMID: 34876155 PMCID: PMC8650507 DOI: 10.1186/s12934-021-01712-1] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 11/23/2021] [Indexed: 12/25/2022] Open
Abstract
Lipid-based biofuels, such as biodiesel and hydroprocessed esters, are a central part of the global initiative to reduce the environmental impact of the transport sector. The vast majority of production is currently from first-generation feedstocks, such as rapeseed oil, and waste cooking oils. However, the increased exploitation of soybean oil and palm oil has led to vast deforestation, smog emissions and heavily impacted on biodiversity in tropical regions. One promising alternative, potentially capable of meeting future demand sustainably, are oleaginous yeasts. Despite being known about for 143 years, there has been an increasing effort in the last decade to develop a viable industrial system, with currently around 100 research papers published annually. In the academic literature, approximately 160 native yeasts have been reported to produce over 20% of their dry weight in a glyceride-rich oil. The most intensively studied oleaginous yeast have been Cutaneotrichosporon oleaginosus (20% of publications), Rhodotorula toruloides (19%) and Yarrowia lipolytica (19%). Oleaginous yeasts have been primarily grown on single saccharides (60%), hydrolysates (26%) or glycerol (19%), and mainly on the mL scale (66%). Process development and genetic modification (7%) have been applied to alter yeast performance and the lipids, towards the production of biofuels (77%), food/supplements (24%), oleochemicals (19%) or animal feed (3%). Despite over a century of research and the recent application of advanced genetic engineering techniques, the industrial production of an economically viable commodity oil substitute remains elusive. This is mainly due to the estimated high production cost, however, over the course of the twenty-first century where climate change will drastically change global food supply networks and direct governmental action will likely be levied at more destructive crops, yeast lipids offer a flexible platform for localised, sustainable lipid production. Based on data from the large majority of oleaginous yeast academic publications, this review is a guide through the history of oleaginous yeast research, an assessment of the best growth and lipid production achieved to date, the various strategies employed towards industrial production and importantly, a critical discussion about what needs to be built on this huge body of work to make producing a yeast-derived, more sustainable, glyceride oil a commercial reality.
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Affiliation(s)
- Felix Abeln
- Department of Chemical Engineering, University of Bath, Bath, BA2 7AY, UK.
- Centre for Sustainable and Circular Technologies, University of Bath, Bath, BA2 7AY, UK.
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Hicks RH, Moreno-Beltrán M, Gore-Lloyd D, Chuck CJ, Henk DA. The Oleaginous Yeast Metschnikowia pulcherrima Displays Killer Activity against Avian-Derived Pathogenic Bacteria. BIOLOGY 2021; 10:biology10121227. [PMID: 34943142 PMCID: PMC8698481 DOI: 10.3390/biology10121227] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 11/11/2021] [Accepted: 11/19/2021] [Indexed: 02/07/2023]
Abstract
Simple Summary Pathogenic bacteria in poultry and the widespread use of antibiotics to manage them are costly in terms of production, environmental risk and human health. Probiotic and other low-cost, non-antibiotic treatments offer attractive alternatives to antibiotic applications, but relatively few of these options exist. In this research, we investigated the potential of an otherwise-useful industrial yeast, Metschnikowia pulcherrima, for the active suppression of poultry pathogenic bacteria. We tested multiple strains of yeast against several important bacterial pathogens and found that the more inhibitory strains of yeast supressed bacterial growth and actively killed the most recalcitrant bacteria. Less aggressive yeast strains could increase the growth of some bacterial strains in some environments. The yeast produced novel molecules in response to the presence of the bacteria and we identified several potential mechanisms by which the yeast inhibited or killed bacteria. Together, these results point towards a useful application of a novel yeast for enhanced, antibiotic-free pathogen control. Abstract Metschnikowia pulcherrima is a non-conventional yeast with potential to be used in biotechnological processes, especially those involving low-cost feedstock exploitation and biocontrol applications. The combination of traits that supports these industrial applications in M. pulcherrima also makes it an attractive option to study in the context of livestock health. In this study, we examined the specific interactions between M. pulcherrima and multiple avian pathogenic bacteria. We tested individual bacteria–yeast interactions and bacterial combinations in both solid and liquid media and in variable nutrient environments. Across multiple isolates of M. pulcherrima, we observed different levels of antimicrobial activity, varying from supporting the growth of competing bacteria through suppression and bacterial killing, and we found that these responses varied depending on the bacterial strains and media. We identified multiple molecular routes, including proteins produced by M. pulcherrima strains, that acted to control these microbial interactions. Furthermore, protein screening revealed that M. pulcherrima strains were induced to produce proteins specifically when exposed to bacterial strains, suggesting that fine-tuned mechanisms allow M. pulcherrima to function as a potential lynchpin in a microbial community.
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Affiliation(s)
- Robert H. Hicks
- Milner Centre for Evolution, University of Bath, Bath BA2 7AY, UK; (R.H.H.); (M.M.-B.); (D.G.-L.)
| | - Mauro Moreno-Beltrán
- Milner Centre for Evolution, University of Bath, Bath BA2 7AY, UK; (R.H.H.); (M.M.-B.); (D.G.-L.)
| | - Deborah Gore-Lloyd
- Milner Centre for Evolution, University of Bath, Bath BA2 7AY, UK; (R.H.H.); (M.M.-B.); (D.G.-L.)
| | | | - Daniel A. Henk
- Milner Centre for Evolution, University of Bath, Bath BA2 7AY, UK; (R.H.H.); (M.M.-B.); (D.G.-L.)
- Correspondence:
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The effect of growth rate on the production and vitality of non-Saccharomyces wine yeast in aerobic fed-batch culture. Bioprocess Biosyst Eng 2021; 44:2655-2665. [PMID: 34499236 DOI: 10.1007/s00449-021-02634-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 09/02/2021] [Indexed: 10/20/2022]
Abstract
Non-Saccharomyces wine yeasts are of increasing importance due to their influence on the organoleptic properties of wine and thus the factors influencing the biomass production of these yeasts, as starter cultures, are of commercial value. Therefore, the effects of growth rates on the biomass yield (Yx/s) and fermentation performance of non-Saccharomyces yeasts at bench and pilot scale were examined. The fermentative performance and (Yx/s) were optimised, in aerobic fed-batch cultivations, to produce commercial wine seed cultures of Lachancea thermotolerans Y1240, Issatchenkia orientalis Y1161 and Metschnikowia pulcherrima Y1337. Saccharomyces cerevisiae (Lalvin EC1118) was used as a benchmark. A Crabtree positive response was shown by L. thermotolerans in a molasses-based industrial medium, at growth rates exceeding 0.21 h-1 (µcrit), resulting in a Yx/s of 0.76 g/g at 0.21 h-1 (46% of µmax) in the aerobic bioreactor-grown fed-batch culture at bench scale. At pilot scale and 0.133 h-1 (36% of µmax), this yeast exhibited ethanol concentrations reaching 10.61 g/l, as a possible result of substrate gradients. Crabtree negative responses were observed for I. orientalis and M. pulcherrima resulting in Yx/s of 0.83 g/g and 0.68 g/g, respectively, below 32% of µmax. The Yx/s of M. pulcherrima, I. orientalis and L. thermotolerans was maximised at growth rates between 0.10 and 0.12 h-1 and the fermentative capacity of these yeasts was maximised at these lower growth rates.
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Karamerou EE, Parsons S, McManus MC, Chuck CJ. Using techno-economic modelling to determine the minimum cost possible for a microbial palm oil substitute. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:57. [PMID: 33663577 PMCID: PMC7934523 DOI: 10.1186/s13068-021-01911-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 02/21/2021] [Indexed: 05/07/2023]
Abstract
BACKGROUND Heterotrophic single-cell oils (SCOs) are one potential replacement to lipid-derived biofuels sourced from first-generation crops such as palm oil. However, despite a large experimental research effort in this area, there are only a handful of techno-economic modelling publications. As such, there is little understanding of whether SCOs are, or could ever be, a potential competitive replacement. To help address this question, we designed a detailed model that coupled a hypothetical heterotroph (using the very best possible biological lipid production) with the largest and most efficient chemical plant design possible. RESULTS Our base case gave a lipid selling price of $1.81/kg for ~ 8,000 tonnes/year production, that could be reduced to $1.20/kg on increasing production to ~ 48,000 tonnes of lipid a year. A range of scenarios to further reduce this cost were then assessed, including using a thermotolerant strain (reducing the cost from $1.20 to $1.15/kg), zero-cost electricity ($ 1.12/kg), using non-sterile conditions ($1.19/kg), wet extraction of lipids ($1.16/kg), continuous production of extracellular lipid ($0.99/kg) and selling the whole yeast cell, including recovering value for the protein and carbohydrate ($0.81/kg). If co-products were produced alongside the lipid then the price could be effectively reduced to $0, depending on the amount of carbon funnelled away from lipid production, as long as the co-product could be sold in excess of $1/kg. CONCLUSIONS The model presented here represents an ideal case that which while not achievable in reality, importantly would not be able to be improved on, irrespective of the scientific advances in this area. From the scenarios explored, it is possible to produce lower cost SCOs, but research must start to be applied in three key areas, firstly designing products where the whole cell is used. Secondly, further work on the product systems that produce lipids extracellularly in a continuous processing methodology or finally that create an effective biorefinery designed to produce a low molecular weight, bulk chemical, alongside the lipid. All other research areas will only ever give incremental gains rather than leading towards an economically competitive, sustainable, microbial oil.
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Affiliation(s)
- Eleni E Karamerou
- Department of Mechanical Engineering, University of Bath, Bath, BA2 7AY, UK
| | - Sophie Parsons
- Department of Mechanical Engineering, University of Bath, Bath, BA2 7AY, UK
| | - Marcelle C McManus
- Department of Mechanical Engineering, University of Bath, Bath, BA2 7AY, UK
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Longanesi L, Bouxin FP, Fan J, Auta H, Gammons R, Abeln F, Budarin VL, Clark JH, Chuck CJ. Scaled-Up Microwave-Assisted Pretreatment and Continuous Fermentation to Produce Yeast Lipids from Brewery Wastes. Ind Eng Chem Res 2020. [DOI: 10.1021/acs.iecr.0c03463] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Luca Longanesi
- Department of Chemical Engineering, University of Bath, Bath BA2 7AY, U.K
| | - Florent P. Bouxin
- Green Chemistry Centre of Excellence, Department of Chemistry, University of York, Heslington, York YO10 5DD, U.K
| | - Jiajun Fan
- Green Chemistry Centre of Excellence, Department of Chemistry, University of York, Heslington, York YO10 5DD, U.K
| | - Hadiza Auta
- Department of Chemical Engineering, University of Bath, Bath BA2 7AY, U.K
| | - Richard Gammons
- Green Chemistry Centre of Excellence, Department of Chemistry, University of York, Heslington, York YO10 5DD, U.K
| | - Felix Abeln
- Department of Chemical Engineering, University of Bath, Bath BA2 7AY, U.K
| | - Vitaliy L. Budarin
- Green Chemistry Centre of Excellence, Department of Chemistry, University of York, Heslington, York YO10 5DD, U.K
| | - James H. Clark
- Green Chemistry Centre of Excellence, Department of Chemistry, University of York, Heslington, York YO10 5DD, U.K
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Abeln F, Hicks RH, Auta H, Moreno-Beltrán M, Longanesi L, Henk DA, Chuck CJ. Semi-continuous pilot-scale microbial oil production with Metschnikowia pulcherrima on starch hydrolysate. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:127. [PMID: 32695223 PMCID: PMC7367368 DOI: 10.1186/s13068-020-01756-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 06/23/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND Heterotrophic microbial oils are potentially a more sustainable alternative to vegetable or fossil oils for food and fuel applications. However, as almost all work in the area is conducted on the laboratory scale, such studies carry limited industrial relevance and do not give a clear indication of what is required to produce an actual industrial process. Metschnikowia pulcherrima is a non-pathogenic industrially promising oleaginous yeast which exhibits numerous advantages for cost-effective lipid production, including a wide substrate uptake, antimicrobial activity and fermentation inhibitor tolerance. In this study, M. pulcherrima was fermented in stirred tank reactors of up to 350 L with 250-L working volume in both batch and semi-continuous operation to highlight the potential industrial relevance. Due to being food-grade, suitable for handling at scale and to demonstrate the oligosaccharide uptake capacity of M. pulcherrima, enzyme-hydrolysed starch in the form of glucose syrup was selected as fermentation feedstock. RESULTS In batch fermentations on the 2-L scale, a lipid concentration of 14.6 g L-1 and productivity of 0.11 g L-1 h-1 were achieved, which was confirmed at 50 L (15.8 g L-1; 0.10 g L-1 h-1). The maximum lipid production rate was 0.33 g L-1 h-1 (daily average), but the substrate uptake rate decreased with oligosaccharide chain length. To produce 1 kg of dry yeast biomass containing up to 43% (w/w) lipids, 5.2 kg of the glucose syrup was required, with a lipid yield of up to 0.21 g g-1 consumed saccharides. In semi-continuous operation, for the first time, an oleaginous yeast was cultured for over 2 months with a relatively stable lipid production rate (around 0.08 g L-1 h-1) and fatty acid profile (degree of fatty acid saturation around 27.6% w/w), and without contamination. On the 250-L scale, comparable results were observed, culminating in the generation of nearly 10 kg lipids with a lipid productivity of 0.10 g L-1 h-1. CONCLUSIONS The results establish the importance of M. pulcherrima for industrial biotechnology and its suitability to commercially produce a food-grade oil. Further improvements in the productivity are required to make M. pulcherrima lipid production industrial reality, particularly when longer-chain saccharides are involved.
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Affiliation(s)
- Felix Abeln
- Centre for Sustainable and Circular Technologies, University of Bath, Bath, UK
- Department of Chemical Engineering, University of Bath, Bath, UK
| | - Robert H. Hicks
- Department of Biology & Biochemistry, University of Bath, Bath, UK
| | - Hadiza Auta
- Department of Chemical Engineering, University of Bath, Bath, UK
| | | | - Luca Longanesi
- Department of Chemical Engineering, University of Bath, Bath, UK
| | - Daniel A. Henk
- Department of Biology & Biochemistry, University of Bath, Bath, UK
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Sipiczki M. Metschnikowia pulcherrima and Related Pulcherrimin-Producing Yeasts: Fuzzy Species Boundaries and Complex Antimicrobial Antagonism. Microorganisms 2020; 8:E1029. [PMID: 32664630 PMCID: PMC7409158 DOI: 10.3390/microorganisms8071029] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 07/08/2020] [Accepted: 07/10/2020] [Indexed: 12/30/2022] Open
Abstract
Yeasts affiliated with the Metschnikowia pulcherrima clade (subclade) of the large ascomycetous genus Metschnikowia frequently turn out to produce the characteristic maroon-red pulcherrimin when tested for pigment production and prove to exert antagonistic effects on many types of microorganisms. The determination of the exact taxonomic position of the strains is hampered by the shortage of distinctive morphological and physiological properties of the species of the clade and the lack of rDNA barcode gaps. The rDNA repeats of the type strains of the species are not homogenized and are assumed to evolve by a birth-and-death mechanism combined with reticulation. The taxonomic division is further hampered by the incomplete biological (reproductive) isolation of the species: certain type strains can be hybridized and genome sequencing revealed chimeric genome structures in certain strains that might have evolved from interspecies hybrids (alloploid genome duplication). Various mechanisms have been proposed for the antimicrobial antagonism. One is related to pulcherrimin production. The diffusible precursor of pulcherrimin, the pulcherriminic acid is secreted by the cells into the environment where it forms the insoluble pulcherrimin with the ferric ions. The lack of free iron caused by the immobilization of ferric ions inhibits the growth of many microorganisms. Recent results of research into the complexity of the taxonomic division of the pulcherrimin-producing Metschnikowia yeasts and the mechanism(s) underlying their antimicrobial antagonism are discussed in this review.
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Affiliation(s)
- Matthias Sipiczki
- Department of Genetics and Applied Microbiology, University of Debrecen, 4032 Debrecen, Hungary
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13
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Wang F, Zhang G, Peng J, Ji X, Hai J, Deng X, Lin L. High cell-density fermentation, expression and purification of bacteriophage lysin TSPphg, a thermostable antimicrobial protein from extremophilic Thermus bacteriophage TSP4. Protein Expr Purif 2020; 174:105676. [PMID: 32442498 DOI: 10.1016/j.pep.2020.105676] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 05/13/2020] [Accepted: 05/17/2020] [Indexed: 12/28/2022]
Abstract
Recently, high cell-density (HCD) cultivation has become an important tool for production of many microbial products. However, to the best of our knowledge, no study regarding HCD fermentation, overproduction and purification of thermostable bacteriophage lysin has been reported. Here, by employing a glucose-limited fed-batch strategy, we performed high density fermentation of the host Escherichia coli BL21(DE3) cells, compared the efficiency of high pressure homogenization, ultrasonication and thermolysis in bacterial cell disruption after HCD cultivation, and purified TSPphg, a thermostable lysin derived from extremophilic bacteriophage TSP4. On the 20-L scale, the overproduction level of TSPphg was up to 67.8 ± 0.7%. In total, we obtained a broth titer of 3322.8 ± 26 mg/L TSPphg with a purity of 95.5 ± 0.7% from a bacterial cell mass of 86.3 ± 4.9 g/L after 26 h of fermentation. The overall productivity of TSPphg was 127.8 ± 1 mg/L/h. Additionally, the antimicrobial activity of purified TSPphg against both Gram-negative (Escherichia coli O157) and Gram-positive (Staphylococcus aureus) pathogenic bacteria was further confirmed by scanning electron microscope analysis. Summarily, for the first time, we have established a relatively stable and efficient HCD cultivation and purification process for recovery of thermostable lysins from extremophilic Thermus bacteriophages. Our results provide insights into the strategies for time-saving and cost-effective production of antimicrobial proteins to replace or supplement antibiotics in the current age of mounting antibiotic resistance.
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Affiliation(s)
- Feng Wang
- Faculty of Life Science and Technology, Kunming University of Science and Technology, 727 South Jingming Road, Chenggong District, Kunming, Yunnan Province, 650500, China
| | - Guanling Zhang
- Faculty of Life Science and Technology, Kunming University of Science and Technology, 727 South Jingming Road, Chenggong District, Kunming, Yunnan Province, 650500, China
| | - Jiani Peng
- Faculty of Life Science and Technology, Kunming University of Science and Technology, 727 South Jingming Road, Chenggong District, Kunming, Yunnan Province, 650500, China
| | - Xinyu Ji
- Faculty of Life Science and Technology, Kunming University of Science and Technology, 727 South Jingming Road, Chenggong District, Kunming, Yunnan Province, 650500, China
| | - Jun Hai
- Faculty of Life Science and Technology, Kunming University of Science and Technology, 727 South Jingming Road, Chenggong District, Kunming, Yunnan Province, 650500, China
| | - Xianyu Deng
- Faculty of Life Science and Technology, Kunming University of Science and Technology, 727 South Jingming Road, Chenggong District, Kunming, Yunnan Province, 650500, China
| | - Lianbing Lin
- Faculty of Life Science and Technology, Kunming University of Science and Technology, 727 South Jingming Road, Chenggong District, Kunming, Yunnan Province, 650500, China; Engineering Research Center for Replacement Technology of Feed Antibiotics of Yunnan College, 727 South Jingming Road, Chenggong District, Kunming, Yunnan Province, 650500, China.
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