BIOCHEMICAL ENGINEERING JOURNAL
·
2020
·
IF 3.475
Guohui Li,Dixuan Huang,Li Wang,Yu Deng
Putrescine is an amine with high industrial value. At present, the chemical production method used in industry has shortcomings of using unsustainable petroleum raw material and expensive reaction catalyst, unsafe reaction process with inflammables and explosives. Therefore, researchers turn their attention to the biosynthesis of putrescine. Escherichia coli , with the natural pathway for the synthesis of putrescine, is a good choice for producing putrescine as the host strain. In this study, an effective putrescine bio-production platform was built via overexpressing two key pathway enzymes in engineered Escherichia coli PUT2, combining with a well-controlled fermentation strategy. Escherichia coli PUT2 converted arginine to putrescine within 48 h on a 3 L scale, reaching a titer of 26.21 g L −1 , and the specific production of putrescine was 1.99 g per unit biomass, with a productivity of 0.54 g L -1 h -1 , which obtained the high production efficiency of cell. Compared with the original strain Escherichia coli BL21(DE3), the putrescine titer increased to 79 times. This research offered a promising strategy for putrescine bio-synthesis, laying a foundation for large-scale putrescine bio-production.
研究领域:
生物技术
·
微生物学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
CATALYSIS LETTERS
·
2021
·Vol. 152
·期 9
·2625-2636
·
IF 3.186
Li Qi,Chai Changsheng,Zhao Linguo
In this paper, five recombinant strains: GS115-LacA, GS115-LacB, GS115-LacC, KM71H-Lcc1 and GS115-Lcc2 were selected to produce laccase isozymes with high activities, which reached 13,001 U/L, 10,254 U/L, 11,495 U/L, 9924 U/L and 10,031 U/L on 15th, respectively. Then, we investigated the specificity of several recombinant laccase isozymes for the degradation of endocrine disrupting chemicals (phenolic compounds). The results showed that LacB had the most efficient in degradation of bisphenol A and octyl phenol, while Lcc1 degraded 4- n -octylphenol, gossypol and hydroquinone better. Finally, the effects of degradation conditions were optimized, which shown that the degradation rates of phenolic compounds increased with the optimum temperature and pH by different laccases were different, which were closely related to their enzymatic properties. Under the optimum reaction conditions, the degradation rate of bisphenol A, gossypol, 4- n -octylphenol, octyl phenol and hydroquinone were 95.4%, 93.2%, 89.6%, 71.0% and 91.9% at 8 h, 8 h, 12 h, 24 h and 1 h, respectively. Furthermore, the recombinant laccases were used to degrade phenolic compounds in several laccase/mediator systems, which ABTS and vanillin showed most enhancement on degradation rates and reduction of degradation times. In LacB-ABTS and Lcc1-guaiacol/vanillin systems, the degradation rates of five phenolic compounds reached the maximum with totally 100% within 4 h. All of the results open up promising perspectives for the degradation and oxidative biotransformation of typical phenolic pollutants in the environment. Graphical Abstract
研究领域:
环境科学
·
生物技术
·
酶学
✓ 已验证
DOI
高影响因子
CHEMOSPHERE
·
2016
·
IF 3.698
Chunyan Li,Zhenlei Yue,Fengzhao Feng,Chuanwu Xi,Hailian Zang,Xuejiao An,Keran Liu
There is a great need for efficient acetonitrile removal technology in wastewater treatment to reduce the discharge of this pollutant in untreated wastewater. In this study, a nitrilase gene ( nit ) isolated from a nitrile-degrading bacterium ( Rhodococcus rhodochrous BX2) was cloned and transformed into a biofilm-forming bacterium ( Bacillus subtilis N4) that expressed the recombinant protein upon isopropylthio-β-galactoside (IPTG) induction. The recombinant bacterium ( B. subtilis N4-pHT01- nit ) formed strong biofilms and had nitrile-degrading capability. Further testing demonstrated that biofilms formed by B. subtilis N4-pHT01- nit were highly resistant to loading shock from acetonitrile and almost completely degraded the initial concentration of acetonitrile (800 mg L −1 ) within 24 h in a moving bed biofilm reactor (MBBR) after operation for 35 d. The bacterial composition of the biofilm, identified by high-throughput sequencing, in a reactor in which the B. subtilis N4-pHT01- nit bacterium was introduced indicated that the engineered bacterium was successfully immobilized in the reactor and became dominant genus. This work demonstrates that an engineered bacterium with nitrile-degrading and biofilm-forming capacity can improve the degradation of contaminants in wastewater. This approach offers a novel strategy for enhancing the biological oxidation of toxic pollutants in wastewater.
研究领域:
环境工程
·
微生物学
·
生物技术
·
污水处理
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2018
·
IF 6.434
Chunyan Li,Yueling Sun,Zhenlei Yue,Mingyan Huang,Jinming Wang,Xi Chen,Xuejiao An,Hailian Zang,Dapeng Li,Ning Hou
The immobilization of organonitrile-degrading bacteria via the addition of biofilm-forming bacteria represents a promising technology for the treatment of organonitrile-containing wastewater, but biofilm-forming bacteria simply mixed with degrading bacteria may reduce the biodegradation efficiency. Nitrile hydratase and amidase genes, which play critical roles in organonitriles degradation, were cloned and transformed into the biofilm-forming bacterium Bacillus subtilis N4 to construct a recombinant bacterium B. subtilis N4/pHT nha - ami . Modified polyethylene carriers with positive charge was applied to promote bacterial adherence and biofilm formation. The immobilized B. subtilis N4/pHT nha - ami was resistant to organonitriles loading shocks and could remove organic cyanide ion with a initial concentration of 392.6 mg/L for 24 h in a moving bed biofilm reactor. The imputed quorum-sensing signal and the high-throughput sequencing analysis of the biofilm indicated that B. subtilis N4/pHT nha-ami was successfully immobilized and became dominant. The successful application of the immobilized recombinant bacterium offers a novel strategy for the biodegradation of recalcitrant compounds.
研究领域:
环境工程
·
生物技术
·
微生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）