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Niu K, Qi YX, Cai HW, Ye YX, Zhou HY, Liu XT, Liu ZQ, Zheng YG. Investigation of the enhancement for Echinocandin B fermentation with methyl oleate from transcription level. Bioprocess Biosyst Eng 2023:10.1007/s00449-023-02883-4. [PMID: 37253987 DOI: 10.1007/s00449-023-02883-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2023] [Accepted: 05/12/2023] [Indexed: 06/01/2023]
Abstract
Echinocandin B (ECB) is the key precursor compound of the antifungal drug Anidulafungin. The effects of the five precursor amino acids on ECB biosynthesis were firstly investigated. It showed that although L-threonine was a main compound of the hexapeptide scaffold of ECB, exogenous addition of L-threonine had no significant effect on the increase of ECB fermentation titer. Meanwhile, the ECB fermentation titer with methyl oleate showed two times higher than that of the other carbon sources. Transcription level analysis of the key genes for ECB biosynthesis indicated that the gene an655543 related to L-threonine biosynthesis showed higher value during the fermentation process, therefore, the exogenous addition of L-threonine had no obvious affection. Furthermore, it indicated that the transcription level of gene ecdA might be the main restriction factor for the ECB biosynthesis. The study provided the research foundation for the modification of the ECB producing strains in the following work.
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Affiliation(s)
- Kun Niu
- The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China
| | - Yu-Xin Qi
- The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China
| | - Hong-Wei Cai
- The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China
| | - Yi-Xin Ye
- The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China
| | - Hai-Yan Zhou
- The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China
| | - Xiao-Tian Liu
- The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China
- School of Chemical and Environmental Engineering, Shanghai Institute of Technology, Shanghai, 200235, People's Republic of China
| | - Zhi-Qiang Liu
- The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China.
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China.
| | - Yu-Guo Zheng
- The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China
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Niu K, Wu XP, Fu Q, Lang KP, Zou SP, Hu ZC, Liu ZQ, Zheng YG. Effects of lipids and surfactants on the fermentation production of echinocandin B by Aspergillus nidulans. J Appl Microbiol 2021; 131:2849-2860. [PMID: 33987908 DOI: 10.1111/jam.15136] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 04/03/2021] [Accepted: 04/28/2021] [Indexed: 11/30/2022]
Abstract
AIMS Echinocandin B (ECB) is a kind of lipopeptide antifungal antibiotic, as well as the key precursor of antifungal drug Anidulafungin. Its efficient bioproduction plays an important role in promoting the industrial production of Anidulafungin. METHODS AND RESULTS In this study, methyl oleate and Tween 80 were firstly used to enhance the ECB fermentation by Aspergillus nidulans, the results showed that the ECB titre was significantly enhanced with the addition of methyl oleate and Tween 80. Among the lipids, methyl oleate was found to play a pivotal role in increasing the ECB titre to 2123 mg l-1 , which was more than five times higher than that of the control. The addition of Tween 80 in the medium resulted in ECB titre increased to 2584 mg l-1 . The scanning electron microscope (SEM) and N-phenyl-1-naphthylamine (NPN) assay indicated that Tween 80 could influence the cell membrane permeability of A. nidulans, and enhance the intracellular and extracellular substance exchange, therefore lead to the increasing of ECB titre. CONCLUSIONS Methyl oleate and Tween 80 are optimal carbon sources and surfactants for efficient ECB biosynthesis respectively. SIGNIFICANCE AND IMPACT OF THE STUDY Surfactant was used in ECB fermentation for the first time, which provided feasible ideas for optimizing the fermentation process of other fungi.
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Affiliation(s)
- K Niu
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, P. R. China
| | - X P Wu
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, P. R. China
| | - Q Fu
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, P. R. China
| | - K P Lang
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, P. R. China
| | - S P Zou
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, P. R. China
| | - Z C Hu
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, P. R. China
| | - Z Q Liu
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, P. R. China
| | - Y G Zheng
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, P. R. China
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Niu K, Wu XP, Hu XL, Zou SP, Hu ZC, Liu ZQ, Zheng YG. Effects of methyl oleate and microparticle-enhanced cultivation on echinocandin B fermentation titer. Bioprocess Biosyst Eng 2020; 43:2009-2015. [PMID: 32557175 DOI: 10.1007/s00449-020-02389-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 06/10/2020] [Indexed: 02/01/2023]
Abstract
Echinocandin B (ECB) is a key precursor of antifungal agent Anidulafungin, which has demonstrated clinical efficacy in patients with invasive candidiasis. In this study, the effects of microparticle-enhanced cultivation and methyl oleate on echinocandin B fermentation titer were investigated. The results showed that the titer was significantly influenced by the morphological type of mycelium, and mycelium pellet was beneficial to improve the titer of this secondary metabolism. First, different carbon sources were chosen for the fermentation, and methyl oleate achieved the highest echinocandin B titer of 2133 ± 50 mg/L, which was two times higher than that of the mannitol. The study further investigated the metabolic process of the fermentation, and the results showed that L-threonine concentration inside the cell could reach 275 mg/L at 168 h with methyl oleate, about 2.5 times higher than that of the mannitol. Therefore, L-threonine may be a key precursor of echinocandin B. In the end, a new method of adding microparticles for improving the mycelial morphology was used, and the addition of talcum powder (20 g/L, diameter of 45 µm) could make the maximum titer of echinocandin B reach 3148 ± 100 mg/L.
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Affiliation(s)
- Kun Niu
- The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China.,Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China
| | - Xu-Ping Wu
- The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China.,Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China
| | - Xiao-Long Hu
- The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China.,Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China
| | - Shu-Ping Zou
- The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China.,Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China
| | - Zhong-Ce Hu
- The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China.,Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China
| | - Zhi-Qiang Liu
- The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China. .,Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China.
| | - Yu-Guo Zheng
- The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China.,Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China
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Hu ZC, Li WJ, Zou SP, Niu K, Zheng YG. Mutagenesis of echinocandin B overproducing Aspergillus nidulans capable of using starch as main carbon source. Prep Biochem Biotechnol 2020; 50:745-752. [PMID: 32125248 DOI: 10.1080/10826068.2020.1734940] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Echinocandin B, a kind of antimycotic with cyclic lipo-hexapeptides, was produced by fermentation with Aspergillus nidulans using fructose as main carbon source. The objective of this study was to screen a high-yield mutant capable of using cheap starch as main carbon source by atmospheric and room temperature plasma (ARTP) treatment in order to decrease the production cost of echinocandin B. A stable mutant A. nidulans ZJB19033, which can use starch as optimal carbon source instead of expensive fructose, was selected from two thousands isolates after several cycles of ARTP mutagenesis. To further increase the production of echinocandin B, the optimization of fermentation medium was performed by response surface methodology (RSM), employing Plackett-Burman design (PBD) followed by Box-Behnken design (BBD). The optimized fermentation medium provided the optimal yield of echinocandin B, 2425.9 ± 43.8 mg/L, 1.3-fold compared to unoptimized medium. The results indicated that the mutant could achieve high echinocandin B production using cheap starch as main carbon source, and the cost of carbon sources in fermentation medium reduced dramatically by about 45%.
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Affiliation(s)
- Zhong-Ce Hu
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, P. R. China
| | - Wen-Jun Li
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, P. R. China
| | - Shu-Ping Zou
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, P. R. China
| | - Kun Niu
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, P. R. China
| | - Yu-Guo Zheng
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, P. R. China
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Shivakumar MC, Manohar S, Ishwar B, Raghu P, Savitha J. Deacylation of Echinocandin B by Streptomyces species: a novel method for the production of Echinocandin B nucleus. 3 Biotech 2019; 9:412. [PMID: 31696017 DOI: 10.1007/s13205-019-1946-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Accepted: 10/10/2019] [Indexed: 10/25/2022] Open
Abstract
Anidulafungin, a new class of antifungal agent used for the treatment of chronic fungal infections, is derived from Echinocandin B nucleus, an intermediate metabolite of Echinocandin B produced by Aspergillus nidulans. The enzyme acylase plays a key role in the bioconversion of Echinocandin B to Echinocandin B nucleus. In the present study, a rapid screening method was used to select an actinomycete capable of producing Echinocandin B acylase. Out of 140 actinomycetes screened for the production of acylase by preliminary qualitative plate assay, 53 were selected. The selected isolates were subjected to quantitative assay under submerged fermentation for the bioconversion of Echinocandin B to Echinocandin B nucleus. Among 53 strains of actinomycetes, two strains (BICC-8848 and BICC-8547) exhibited higher degree of acylase activity. Various physico-chemical parameters were optimised for maximum bioconversion of ECB to ECB nucleus. It was found that the conditions viz. pH 7.0, temperature 26 °C and substrate concentration of about 4 g/L supported higher degree of bioconversion. It was also observed that, as the medium volume increased to 500 mL, the conversion rate was also increased by more than two-folds.
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Zou SP, Xiong Y, Niu K, Hu ZC, Zheng YG. Integrated strategy of temperature shift and mannitol feeding for enhanced production of echinocandin B by Aspergillus nidulans CCTCC M2012300. 3 Biotech 2019; 9:140. [PMID: 30944787 PMCID: PMC6419687 DOI: 10.1007/s13205-019-1668-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Accepted: 03/05/2019] [Indexed: 12/12/2022] Open
Abstract
The production of echinocandin B (ECB) by Aspergillus nidulans CCTCC M2012300 was improved by integrating the temperature-shift and fed-batch control strategies. The kinetic characteristics of batch cultures were analyzed at different culture temperatures, and then a two-stage temperature control strategy was established. In the first 6 days, the temperature was maintained at 30 °C to obtain the maximal cell growth rate; subsequently, 25 °C was used to gain a high ECB formation rate. On the basis of temperature control, the ECB productivity was increased to 143.3 mg/(L day), which was a 1.3-fold improvement compared with the optimal constant-temperature cultivations. The influences of fed-batch cultures were further investigated. A maximal ECB productivity of 170.8 mg/(L day) was obtained through a three-stage mannitol pulse-feeding strategy, which was another 1.2-fold improvement than that of the batch fermentation. This is the first report of the use of a two-stage temperature control fed-batch strategy in ECB fermentation. This strategy was simple and economical to operate and may provide new guidance for the industrial-scale production of ECB.
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Affiliation(s)
- Shu-Ping Zou
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014 China
- Engineering Research Center of Bioconversion and Biopurification of Ministry of Education, Zhejiang University of Technology, Hangzhou, 310014 China
| | - Yan Xiong
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014 China
- Engineering Research Center of Bioconversion and Biopurification of Ministry of Education, Zhejiang University of Technology, Hangzhou, 310014 China
| | - Kun Niu
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014 China
- Engineering Research Center of Bioconversion and Biopurification of Ministry of Education, Zhejiang University of Technology, Hangzhou, 310014 China
| | - Zhong-Ce Hu
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014 China
- Engineering Research Center of Bioconversion and Biopurification of Ministry of Education, Zhejiang University of Technology, Hangzhou, 310014 China
| | - Yu-Guo Zheng
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014 China
- Engineering Research Center of Bioconversion and Biopurification of Ministry of Education, Zhejiang University of Technology, Hangzhou, 310014 China
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Kumar A, Jaiswal V, Kumar V, Dey A, Kumar A. Functional redundancy in Echinocandin B in-cluster transcription factor ecdB of Emericella rugulosa NRRL 11440. Biotechnol Rep (Amst) 2018; 19:e00264. [PMID: 29992098 PMCID: PMC6036647 DOI: 10.1016/j.btre.2018.e00264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 05/15/2018] [Accepted: 06/07/2018] [Indexed: 10/30/2022]
Abstract
Echinocandin B is a potent antifungal against the majority of fungal pathogens and its biosynthesis occurred by ecd and hty gene clusters in Emericella rugulosa NRRL 11440. We elucidated the functional necessity of in-clustered transcription factor; ecdB in the production of echinocandin B. We deleted the ecdB gene and found that ΔecdB mutant has no significant effect on echinocandin B production. The expression level of most of the ecd and hty cluster genes was not significantly altered except few of them up-regulated in knockout strain. The complete abrogation in ecdB gene expression was observed in ΔecdB strain. However, the interactions of purified EcdB protein with DNA sequence of ecdA, ecdH, ecdK and ecdI promoter was confirmed in-vitro. Our results conclude that EcdB protein in-vitro binds to the ecdA, ecdH, ecdK and ecdI promoter but in-vivo, it could not significantly affect the gene expression and echinocandin B production in Emericella rugulosa.
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Key Words
- Arg, Arginine
- Biosynthetic regulation
- CTAB, cetyl trimethylammonium bromide
- ECB, echinocandin B
- Echinocandin B
- Emericella rugulosa
- Functional redundancy
- GMM, glucose minimal medium
- HPLC, high performance liquid chromatography
- ICU, intensive care unit
- In-clustered transcription factor
- MEGA, molecular evolutionary genetics analysis
- MP, maximum parsimony
- ORF, open reading frame
- PCR, polymerase chain reaction
- RT-PCR, reverse transcription polymerase chain reaction
- SPR, subtree-pruning-regrafting
- TF, transcription factor
- UTR, un-translated region
- WT, wild type
- YG, yeast glucose medium
- bp, base pair
- d, day
- h, hour
- kb, kilo base pair
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Affiliation(s)
- Arvind Kumar
- Centre for Biological Science (Biotechnology), Central University of South Bihar, BIT Campus, P.O. B. V. College, Patna, 800014, India
| | - Varun Jaiswal
- School of Electrical and Computer Science Engineering, Shoolini University, Oachghat-Kumarhatti Highway, Bajol, Solan, 173229, India
| | - Vinay Kumar
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Amitava Dey
- Division of Livestock and Fisheries Management, ICAR-Research Complex for Eastern Region, Phulwari Road, Patna, 800014, India
| | - Antresh Kumar
- Centre for Biological Science (Biotechnology), Central University of South Bihar, BIT Campus, P.O. B. V. College, Patna, 800014, India
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Zou SP, Zhong W, Xia CJ, Gu YN, Niu K, Zheng YG, Shen YC. Mutagenesis breeding of high echinocandin B producing strain and further titer improvement with culture medium optimization. Bioprocess Biosyst Eng 2015; 38:1845-54. [PMID: 26091897 DOI: 10.1007/s00449-015-1425-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2014] [Accepted: 06/09/2015] [Indexed: 10/23/2022]
Abstract
A combination of microbial strain improvement and statistical optimization is investigated to maximize echinocandin B (ECB) production from Aspergillus nidulans ZJB-0817. A classical sequential mutagenesis was studied first by using physical (ultraviolet irradiation at 254 nm) and chemical mutagens (lithium chloride and sodium nitrite). Mutant strain ULN-59 exhibited 2.1-fold increase in ECB production to 1583.1 ± 40.9 mg/L when compared with the parent strain (750.8 ± 32.0 mg/L). This is the first report where mutagenesis is applied in Aspergillus to improve ECB production. Further, fractional factorial design and central composite design were adopted to optimize the culture medium for increasing ECB production by the mutant ULN-59. Results indicated that four culture media including peptone, K2HPO4, mannitol and L-ornithine had significant effects on ECB production. The optimized medium provided another 1.4-fold increase in final ECB concentration to 2285.6 ± 35.6 mg/L compared to the original medium. The results of this study indicated the combined application of a classical mutation and medium optimization can improve effectively ECB production from A. nidulans and could be a promising tool to improve other secondary metabolites production by fungal strains.
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Abstract
Pairwise interactions between four antifungal compounds were studied. The β-1,3-glucan synthase inhibitor echinocandin B (ECB) showed synergistic effect with the cell wall hydrolase ChiB chitinase and EngA β-1,3-glucanase on Saccharomyces cerevisiae, Candida albicans, Aspergillus rugulosus and A. fumigatus. The antifungal protein of Penicillium chrysogenum (PAF) did not influence the antifungal activity of ChiB or EngA, but showed antagonistic effect with ECB on A. nidulans, A. rugulosus and A. fumigatus. PAF had no significant effect on the growth of the tested yeasts as it was expected and did not influence significantly the antifungal activity of ECB, ChiB or EngA against yeasts.
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Affiliation(s)
- Viktória Tóth
- University of Debrecen Department of Microbial Biotechnology and Cell Biology Debrecen Hungary
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