APPLIED MICROBIOLOGY AND BIOTECHNOLOGY
·
2013
·Vol. 97
·期 17
·7597-7605
·
IF 3.689
Xia Jun,Xu Hong,Feng Xiaohai,Xu Zhaoxian,Chi Bo
Poly(ε- l -lysine) (ε-PL) producer strain Streptomyces albulus PD-1 secreted a novel polymeric substance into its culture broth along with ε-PL. The polymeric substance was purified to homogeneity and identified. Matrix-assisted laser desorption ionization-time of flight mass spectrometry and nuclear magnetic resonance spectroscopy as well as other analytical techniques revealed that the substance was poly( l -diaminopropionic acid) (PDAP). PDAP is an l -α,β-diaminopropionic acid oligomer linking between amino and carboxylic acid functional groups. The molecular weight of PDAP ranged from 500 to 1500 Da, and no co-polymers composed of l -diaminopropionic acid and l -lysine were present in the culture broth. Compared with ε-PL, PDAP exhibited stronger inhibitory activities against yeasts but weaker activities against bacteria. ε-PL and PDAP co-production was also investigated. Both ε-PL and PDAP were synthesized during the stationary phase of growth, and the final ε-PL and PDAP concentration reached 21.7 and 4.8 g L -1 , respectively, in fed-batch fermentation. Citric acid feeding resulted in a maximum ε-PL concentration of 26.1 g L -1 and a decrease in the final concentration of PDAP to 3.8 g L -1 . No studies on ε-PL and PDAP co-production in Streptomyces albulus have been reported previously, and inhibition of by-products such as PDAP is potentially useful in ε-PL production.
研究领域:
微生物学
·
生物化学
·
分子生物学
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2025
·
IF 13.2
Chenghao Fu,Wenjuan Dai,Aoxiang Liu,Yongxuan Liu,Qingshou Yao,Linghui Kong,Bo Yu,Xiuwen Wang,Jiayang Qin
ε-Poly- l -lysine (ε-PL), typically comprising 25–35 l -lysine residues, is a natural homopolymer with potent antibacterial properties. Its wider use is limited by two key challenges: precise control over peptide chain length and low production yields of low-molecular-weight (low-MW) ε-PL variants. In this study, we addressed these constraints by combining genetic engineering, carbon source modulation, and fermentation optimisation, enabling the targeted production of four well-characterised ε-PL variants. Multiple genetically engineered strains of Streptomyces albulus were developed and evaluated for ε-PL chain distribution. Particularly, S. albulus CICC-Pls880-LysP— co -overexpression of a mutated polylysine synthetase (Pls S880I) and a lysine importer (LysP)—produced ε-PL with chain lengths between 23 and 31 residues when grown in glucose-enriched fermentation broth and between 19 and 30 residues in glycerol-enriched broth. By contrast, the parental strain CICC-Pls-LysP yielded longer polymers (28–34 residues in glucose and 25–32 in glycerol), confirming the effectiveness of enzyme engineering in modulating chain length. Subsequent statistical optimisation of the fermentation medium, coupled with fed-batch cultivation strategies, enabled all four ε-PL variants (28–34, 25–32, 23–31, and 19–30 mer) to achieve production titres exceeding 50 g/L. Notably, supplementing l -lysine during fermentation significantly enhanced the yield of the low-MW variant (23–31 mer), reaching to 75.35 g/L. Antibacterial activity assays revealed a distinct correlation between chain length and efficacy, providing valuable insights into the structure–function relationships of ε-PL. This method, established for selectively synthesising ε-PL variants, overcomes historical yield bottlenecks for low-MW ε-PL, thereby broadening the applications of ε-PL.
研究领域:
生物技术
·
微生物发酵
·
合成生物学
·
高分子科学
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应用微生物学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF BASIC MICROBIOLOGY
·
2015
·Vol. 55
·期 9
·1104-1117
·
IF 1.823
Yuncheng Wu,Jun Yuan,Yaoyao E,Waseem Raza,Qirong Shen,Qiwei Huang
A Streptomyces albulus strain NJZJSA2 was isolated from the forest soil sample of Tzu-chin Mountain (Nanjing China) and identified based on its morphological and physiological properties and 16S rDNA gene sequence analysis. The strain S. albulus NJZJSA2 was evaluated for the production of antifungal volatile organic compounds (VOCs) against two fungal pathogens. Results showed that the VOCs generated by S. albulus NJZJSA2 inhibited mycelial growth of Sclerotinia sclerotiorum (SS) and Fusarium oxysporum (FO) by 100 and 56.3%, respectively. The germination of SS sclerotia and FO conidia was completely inhibited in the presence of VOCs produced by S. albulus NJZJSA2 in vitro . In soil, the VOCs delayed the germination of SS sclerotia and inhibited the germination of FO conidia for 45 days. The strain S. albulus NJZJSA2 was able to produce 13 VOCs based on GC/MS analyses. Among those, six compounds were purchased and used for the antifungal activity assay. Three relatively abundant VOCs, 4-methoxystyrene, 2-pentylfuran, and anisole were proved to have antifungal activity. Microscopy analysis showed that the pathogen hyphae were shriveled and damaged after treatment with 4-methoxystyrene. These results suggest that the S. albulus strain NJZJSA2 produce VOCs that not only reduce the growth of SS and FO, but also significantly inhibit the SS sclerotia and FO conidia. The results are useful for the better understanding of biocontrol mechanisms by S. albulus strains and will help to improve the biological control efficiency of lethal plant diseases.
研究领域:
微生物学
·
植物病理学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
PREPARATIVE BIOCHEMISTRY & BIOTECHNOLOGY
·
2022
·
IF 3.141
Yi Zhang,Jing Bai,Chenqi Wu,Yue Wang,Xin Ju,Xin Qi,Liangzhi Li,Lilian Ji,Jiaolong Fu
ε-Poly-l-lysine (ε-PL) is used as a natural food preservative which consists of l-lysine units connected. However, due to the expensive culture medium, the production cost of ε-PL remains high. In this study, cheap raw materials cassava starch (CS) and fish meal (FM) were employed by S. albulus FQC-24 for ε-PL production. In the single factor experiment, the maximum ε-PL production reached 0.97 g/L at 60 g/L CS and 15 g/L FM. The results of screening experiments by Plackett–Burman design showed that three main components affecting ε-PL production were CS, FM, and (NH4)2SO4. And the standardized effects of CS, FM, and (NH4)2SO4 were 0.13, −0.22, and −0.2, respectively. The optimum fermentation medium developed by response surface methodology for ε-PL production contained (g/L) CS, 67.56; FM, 14.70 and (NH4)2SO4, 5.41. Under the optimum conditions, the ε-PL production was achieved 1.30 g/L, with 34.02% higher than that before optimization. Moreover, ε-PL productions of batch and fed-batch fermentation in a 7-L fermentor were improved to 2.13 and 17.17 g/L respectively, which increased by 0.64 and 12.2 times compared with the shake flask culture. The results indicated that FM and CS are promising substrates for the efficient production of ε-PL.
研究领域:
生物技术
·
微生物学
·
食品科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
BIORESOURCE TECHNOLOGY
·
2021
·
IF 9.642
Cheng Wang,Xi Chen,Yingying Jiang,Na Li,Ping Zhu,Hong Xu
Facile and green fabrication of reduced graphene oxide on loofah sponge (rGOLS) carrier was applied for cell immobilization of ε-Poly- l -lysine (ε-PL) production. Due to surface properties including large specific surface area, high polarity, and low interaction energy, rGOLS-1 was employed as the optimum rGOLS to enhance immobilization of Streptomyces albulus . Compared with raw LS, batch experiments showed rGOLS-1 facilitated superior cell vitality for ε-PL production due to the presence of reduced graphene oxide. In the sequential fed-batch cultivation of Streptomyces albulus using rGOLS-1 with an aerobic plant fibrous-bed bioreactor (rGOLS-1-AFPB), the maximum ε-PL concentration and productivity reached to 39.2 ± 0.63 g/L and 0.48 g/L/h. The cells immobilized in rGOLS-1 with high vitality and ε-PL production efficiency were reused six times over a period of 624 h. This research afforded an effective approach to enhance the fermentation performance of immobilized cells with the design of an advanced immobilization carrier.
研究领域:
生物工程
·
微生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
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