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1. Improving natamycin production of <i>Streptomyces gilvosporeus</i> by ARTP mutagenesis combined with 2-deoxyglucose | |||
Wen Xiao,Liang Wang,Hongjian Zhang,Xunsheng Chen,Jianhua Zhang | |||
Biology 01 March 2024 | |||
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Abstract:Natamycin is a polyene macrocyclic antibiotic extensively used in food, medical, and agricultural industries. However, due to high cost and low production efficiency, the current production level fails to meet the growing market demand. Therefore, it is necessary to establish a suitable strain breeding method to improve the production efficiency of natamycin-producing strains. Here, we first assessed the breeding efficiency of 16 different mutagenesis methods and found that the combination of Atmospheric and Room Temperature Plasma (ARTP) with 2-deoxyglucose tolerance exhibited the highest breeding efficiency. After two rounds of screening with the optimal strategy, a high-producing mutant, <i>Streptomyces gilvosporeus</i> AG-2, was obtained. This strain exhibited an enhanced natamycin production of 1.53 g/L, 80% higher than the parent strain <i>S. gilvosporeus</i> ATCC 13326. Further research reveals that the high production of AG-2 may be due to the changes in the transcription levels of the natamycin biosynthetic gene clusters and key enzyme genes related to precursor synthesis, including glucose-6-phosphate dehydrogenase, citrate synthase, and acetyl-CoA carboxylase. The obtained <i>S. gilvosporeus</i> mutant in this study can be used to develop advanced cell factories for the production of natamycin and other value-added bioproducts. | |||
TO cite this article:Wen Xiao,Liang Wang,Hongjian Zhang, et al. Improving natamycin production of <i>Streptomyces gilvosporeus</i> by ARTP mutagenesis combined with 2-deoxyglucose[OL].[ 1 March 2024] http://en.paper.edu.cn/en_releasepaper/content/4762375 |
2. High Throughput Screening of High Nisin-Producing <i>Lactococcus lactis</i> Through Heavy Ion Irradiation And EMS Compound Mutagenesis | |||
Chen Zulian,Wang Liang,Zhang Shijie,Zhang Hongjian,Chen Xusheng,Zhang Jianhua | |||
Biology 29 February 2024 | |||
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Abstract:Nisin is a natural cationic antimicrobial peptide that has been widely used in the fields of food additives, cosmetics, and medicine. Low screening efficiency is the main limiting factor for obtaining high nisin-producing <i>Lactococcus lactis</i>. Here, a high-throughput screening method was established and optimized for the rapid identification of high nisin-producing strains, based on microplate culture and microbial turbidity detection. Using this method, the nisin titer of <i>L. lactis</i> CGMCC1.2829 was rapidly improved through EMS and heavy ion irradiation compound mutagenesis. Among the 3901 mutants obtained during the two rounds of mutagenesis, <i>L. lactis</i> EZ1703 was obtained with the highest nisin titer (4035.91 IU/mL), 3.81 fold compared to the original strain. In a 1 L fermenter, the nisin titer of EZ1703 was 5726.52 IU/mL, which is 6.37 times higher than that of the original strain. Further study showed that changes in cell morphology as well as the transcriptional levels of <i>nisZ</i>, <i>nisC</i>, <i>nisI</i>, <i>nisF</i>, and <i>nisG</i> in EZ1703 are important factors for the improved nisin titer. The present study was the first to improve the nisin titer using high-throughput screening method and heavy ion irradiation technology, and the obtained L. lactis mutant can be used to develop advanced cell factories for the production of nisin. | |||
TO cite this article:Chen Zulian,Wang Liang,Zhang Shijie, et al. High Throughput Screening of High Nisin-Producing <i>Lactococcus lactis</i> Through Heavy Ion Irradiation And EMS Compound Mutagenesis[OL].[29 February 2024] http://en.paper.edu.cn/en_releasepaper/content/4762366 |
3. Production of 1,4-butanediol from succinic acid using Escherichia coli whole-cell catalysis | |||
Ping Ni,Cong Gao,Jing Wu,Wei Song,Xiaomin Li,Wanqing Wei,Xiulai Chen,Liming Liu | |||
Biology 27 February 2024 | |||
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Abstract:The microbial production of 1,4-butanediol (1,4-BDO), a crucial bulk chemical used in the organic chemical and food industries, has attracted increasing attention due to environmental concerns. However, its biosynthetic efficiency via current biotransformation routes is limited. In this study, a dual-pathway approach for 1,4-BDO production from succinic acid was developed. Specifically, a double-enzyme catalytic pathway involving carboxylic acid reductase and ethanol dehydrogenase was proposed. Optimization of the expression levels of the pathway enzymes led to a significant 318% increase in 1,4-BDO titer. Additionally, the rate-limiting enzyme MmCar was engineered to enhance substrate affinity by 50% and increase 1,4-BDO titer by 46.7%. To address cofactor supply limitations, an NADPH and ATP cycling system was established, resulting in a 48.9% increase in 1,4-BDO production. Ultimately, after 48 hours, 1,4-BDO titers reached 201 mg/L and 1555 mg/L in shake flask and 5 L fermenter, respectively. This work represents a significant advancement in 1,4-BDO synthesis from succinic acid, with potential applications in the organic chemical and food industries. | |||
TO cite this article:Ping Ni,Cong Gao,Jing Wu, et al. Production of 1,4-butanediol from succinic acid using Escherichia coli whole-cell catalysis[OL].[27 February 2024] http://en.paper.edu.cn/en_releasepaper/content/4762275 |
4. Optimization of ultrasound-mediated DNA transfer for bacteria and preservation of frozen competent cells | |||
ZHANG Meng,TANG Rongkang,LI Fangxia,JIN Wenyu,Guo Jiaxin,TENG Linzuo,MENG Guangxun,Philippe Joseph Sansonetti,GAO Yizhou | |||
Biology 27 January 2024 | |||
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Abstract:The transformation of DNA into cells is the basis of molecular biology. Common techniques include heat shock transformation, electro-transformation, conjugation, transduction, and protoplast fusion. Ultrasonic transformation technology has recently been developed to transfer DNA into competent cells. The transformation conditions, such as temperature and ultrasonic power, were studied preliminarily. However, this technique has not been widely applied because competent cells must be prepared de novo. In this study, various factors, such as ultrasonic frequency and power, were optimized for the ultrasonic transformation of Escherichia coli. The study found that the optimal conditions for ultrasonic transformation with a defined ultrasonic transformation (UT) vial were a frequency of 28 kHz and a power of 80 W. Meanwhile, this research discovered that combining the 42 C heat shock conditions with ultrasonic transformation is the most efficient method compared to using only heat shock. Additionally, the cryoprotective agents (CPAs) ratio for ultrasonic competent cells was researched and optimized. These findings provide new ideas for improving transformation efficiency and lay a foundation for expanding the application of ultrasonic transformation. | |||
TO cite this article:ZHANG Meng,TANG Rongkang,LI Fangxia, et al. Optimization of ultrasound-mediated DNA transfer for bacteria and preservation of frozen competent cells[OL].[27 January 2024] http://en.paper.edu.cn/en_releasepaper/content/4762038 |
5. Screening of strains from reconstituted tobacco sheet making high-yield enzymes and aroma | |||
Yang Chunxue,Deng Zhang,Liao xiang ru,Guan Zhengbing | |||
Biology 01 March 2023 | |||
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Abstract:Reconstituted tobacco sheet (RTS) is critical to reduce the harm of cigarettes and considered as a comprehensive utilization approach for tobacco wastes in the tobacco industries. The aim of this study was to screen out bacteria from RTS materials capable of producing a high total amount of enzymes and aroma. A total of 21 strains with unique morphologies were obtained. Based on the results of enzymes and aroma producing capacities of the strains, one strain was screened. This strain, which was named B-NS-7, was capable of producing a total amount of 696.3 U/mL protease activity, 238.4 U/mL amylase activity, 64.3 U/mL pectinase activity and 100.0 μg/mL aroma. Combined with the results of the 16S rDNA sequencing, physiological and biochemical characteristics B-NS-7 was identified as Bacillus subtilis. Through a series of single factor experiences, the results showed that under the conditions of inoculation concentration of 1%, fermentation temperature of 37 C and time of 24 h, the highest aroma content of concentrated solutions were 116.3 μg/mL. Neophytadiene was responsible for the majority of the fragrance enhancement, and B-NS-7 was identified as an aldehydic and alkene-flavoured strain. The sensory quality of tobacco concentration solutions was superior under optimal conditions. This strain has been deposited at the China General Microbiological Culture Collection Center (CGMCC No. 23716). By way of this study, B. subtilis B-NS-7 was intended to be used in the manufacturing of RTS through microbial fermentation to improve the quality and providing suggestions for the microbial development of the RTS industry. | |||
TO cite this article:Yang Chunxue,Deng Zhang,Liao xiang ru, et al. Screening of strains from reconstituted tobacco sheet making high-yield enzymes and aroma[OL].[ 1 March 2023] http://en.paper.edu.cn/en_releasepaper/content/4759360 |
6. Recombinant expression, fermentation and characterization of a type Ⅲ human like collagen | |||
XIANG Zhixiang,GONG Jingsong,XU Zhenghong,SHI Jingsong | |||
Biology 12 May 2022 | |||
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Abstract:Collagen, the highest content protein in the body, as irreplaceable biological functions, and it is widespread concerned in food, beauty, and medicine with great market demand. The gene encoding hlCOLⅢ α1 chain fragment was integrated into Pichia pastoris genome after partial amino acids were substituted. Combined with promoter engineering and high-density fermentation technology, soluble secretory expression with the highest yield of 1.05 g L-1 was achieved using two-stage feeding method, and the purity could reach 96% after affinity purification. The determination of N/C-terminal protein sequence were consistent with the theoretical expectation, glycine shared 27.02% and proline 23.92% in amino acid analysis, which were in accordance with the characteristics of collagen. Mass spectrometry combined with Fourier transform infrared spectroscopy and circular dichroism revealed that the target product existed as homologous dimer and trimer in the broth , which laid a foundation for exploring the self-assembly of collagen. | |||
TO cite this article:XIANG Zhixiang,GONG Jingsong,XU Zhenghong, et al. Recombinant expression, fermentation and characterization of a type Ⅲ human like collagen[OL].[12 May 2022] http://en.paper.edu.cn/en_releasepaper/content/4757718 |
7. Comparative transcriptome analysis reveals the mechanism of enhanced microbial hyaluronan biosynthesis | |||
Yao Zhiyuan,Gong Jinsong,Su Chang,Li Heng,Xu Zhenghong,Shi Jinsong | |||
Biology 11 May 2022 | |||
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Abstract:This study reveals the genetic and biochemical changes underlying the enhanced hyaluronan (HA) biosynthesis in Streptococcus zooepidemicus. The selected mutants performed a steady improvement of HA yield after multiple rounds of atmospheric and room temperature plasma (ARTP) mutagenesis combining with novel bovine serum albumin / cetyltrimethylammonium bromide coupled high-throughput screening assay. Compared to the corresponding wild type strains, the HA yield of the obtained mutant (mutant-A17) greatly increased by 42.9% with concomitant accelerated growth. Transcriptome sequencing exhibits that distinct mutants have similar genetic changes. Regulation in direction of metabolic flow into the HA biosynthesis, by enhancing genes responsible for the biosynthesis of HA including hasB, glmU and glmM, weaking downstream gene (nagA and nagB) of UDP-GlcNAc and significantly down-regulating transcription of wall-synthesizing genes, which could cause accumulation of precursors. These associated regulatory genes may provide control point for the efficient synthesis of HA and engineering of the HA-producing cell factory. | |||
TO cite this article:Yao Zhiyuan,Gong Jinsong,Su Chang, et al. Comparative transcriptome analysis reveals the mechanism of enhanced microbial hyaluronan biosynthesis[OL].[11 May 2022] http://en.paper.edu.cn/en_releasepaper/content/4757714 |
8. Characterization and isolation of estradiol degrading bacteria Acinetobacter sp. (7-1) Isolated from Changchun, China. | |||
YU Jian,ZHAO yanyang,HOU yue | |||
Biology 15 December 2020 | |||
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Abstract:17β- Estradiol, as a major environmental estrogen, is a serious threat to human health and ecological security. The MS medium containing 0.5 mM estradiol as the sole carbon source was used to isolate a new Gram-negative bacteria from the fishing pond. This screening strain can use as the sole carbon source and energy source such as estradiol and testosterone. After 16S rRNA analysis, the bacteria belong to Acinetobacter sp with 99.71% identity. The strain was Gram-negative bacilli, Spherical, Blunt round ends, Scattered or arranged in pairs, No bud, No flagella. Size 2.126μm×0.753μm; Conditions for optimum degradation of estradiol were 27℃, 150 rpm, and substrate concentration was 1 mM/L, pH7.5 and 1% inoculum. The highest degradation rate, the degradation rate can reach 85%. The strain could grow normally in 5 μg/mL auromycin, but not in 100 μg/mL ampicillin,50 μg/mL kanamycin,10 μg/mL streptomycin. The degradation rate of 17β- estradiol was 81.4%, that of testosterone was 64.6%, that of progesterone was 44.6%, and that of 17α- ethinyl estradiol was 62.3% by high performance liquid chromatography. | |||
TO cite this article:YU Jian,ZHAO yanyang,HOU yue. Characterization and isolation of estradiol degrading bacteria Acinetobacter sp. (7-1) Isolated from Changchun, China.[OL].[15 December 2020] http://en.paper.edu.cn/en_releasepaper/content/4753226 |
9. Pestalotiopsis castanicola sp. nov., a new endophytic fungus from Yunnan in China | |||
ZHOU Yingke,HOU Chenglin | |||
Biology 16 April 2018 | |||
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Abstract:A new endophytic fungus, Pestalotiopsis castanicola (Amphisphaeriaceae, Ascomycota) on host of Castanopsis carlesii var. spinulosa, was described. Most lateral appendages in Pestalotiopsis lie on the apical cells. While P. castanicola has 2?4 lateral appendages on which lie the septum separating the apical cell and upper median cell. The placement of the lateral appendages in P. castanicola is similar to that in P. montellica and P. jesteri, but the conidial morphology among P. castanicola, P. montellica and P. jesteri has apparent differences. A phylogenetic analysis of the combined sequence data of internal transcribed spacer (ITS), partial ?-tublin (TUB) and partial translation elongation factor1-alpha (TEF) indicated that P. castanicola formed an independent branch in genus of Pestalotiopsis. | |||
TO cite this article:ZHOU Yingke,HOU Chenglin. Pestalotiopsis castanicola sp. nov., a new endophytic fungus from Yunnan in China[OL].[16 April 2018] http://en.paper.edu.cn/en_releasepaper/content/4744533 |
10. Two new Hypohelion species from Southwest China | |||
Lv Tu,HOU Chenglin | |||
Biology 16 April 2018 | |||
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Abstract:Only four species of Hypohelion (Rhytismataceae) have been reported worldwide. In the present study, two new species of Hypohelion, Hypohelion bifusiforme and Hypohelion ventricosum, are described on living twigs of Ericaceae from Southwest China. Bifusiform ascospores and intraepidermal ascoma development are two conspicuous characteristics of the two new species, by which they can be distinguished from other species of Hypohelion. By its apically strongly swollen paraphyses, H. ventricosum differs from H. bifusiforme. The phylogenetic position of the two species within Rhytismataceae was analyzed based on the combined sequences of LSU rDNA, ITS rDNA and mtSSU rDNA. Although the other species of Hypohelion and some species of other genera of Rhytismataceae formed a strongly supported evolutionary clade, a resolution on the genus level was not yet possible. | |||
TO cite this article:Lv Tu,HOU Chenglin. Two new Hypohelion species from Southwest China[OL].[16 April 2018] http://en.paper.edu.cn/en_releasepaper/content/4744532 |
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