BIORESOURCE TECHNOLOGY
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2017
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IF 5.651
Cai Hui,Xiaoxiao Guo,Pengfei Sun,Rashid Azim Khan,Qichun Zhang,Yongchao Liang,Yu-Hua Zhao
A newly verified adsorbent biofilm produced by Bacillus amyloliquefaciens DT was investigated for nitrite removal from aqueous solutions. The biofilm’s characteristics and adsorption mechanism were determined, with results indicating that nitrite ions were adsorbed onto the protonated amine sites of biofilm under acidic conditions. Analysis of various factors showed that higher nitrite adsorption capacities occurred at pH < 3.0 and higher temperatures as well as higher initial nitrite concentrations, with a maximum nitrite removal capacity of 116.84 mg/g. Furthermore, nitrite adsorption was well fitted to the pseudo second-order and Weber–Morris kinetic models, and the Freundlich and Sips isotherm models. Simultaneously, thermodynamic analysis demonstrated that nitrite adsorption is a spontaneous endothermic process. In summary, the adsorption of nitrite was complex, and mainly resulted from electrostatic attraction and intraparticle diffusion. Consequently, the B. amyloliquefaciens biofilm can be considered as a promising adsorbent for nitrite removal from wastewater.
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ENZYME AND MICROBIAL TECHNOLOGY
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2020
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IF 3.448
Zelong Li,Runtao Zhu,Yongqi Liu,Jiaqi Li,Haofeng Gao,Nan Hu
L-theanine, a unique amino acid in green tea with health benefits, can be enzymatically synthesized by γ-glutamyltranspeptidase (γ-GT; EC 2.3.2.2). Here, a salt-tolerant γ-glutamyltranspeptidase from a marine bacterium Bacillus amyloliquefaciens was expressed in Escherichia. coli BL21 (DE3) and was shown to be optimally active at 55 °C, pH 8.5 and alkali stable. A mutant, with higher transpeptidation activity, was obtained following two rounds of directed evolution using error-prone PCR and site-saturation mutagenesis. The mutation increased the ratio of transpeptidation to hydrolysis from 1.6 to 35.6. Additionally, Kinetic analysis exhibited 17.5% decrease of K m , 13.0-fold increase of K cat , and 16.3-fold increase of K cat / K m in mutant V319A/S437 G versus the wild-type. The 3-D modelling analysis revealed a tighter binding pocket in mutant V319A/S437 G. The frequency of hydrogen bond between donor substrate and two residues in the catalytic pocket (Gly437 and Thr375) was enhanced, which stabilized the ligand binding and thus improved the catalytic efficiency. The optimal conditions for the biocatalytic synthesis were determined as pH 10.0, 20 μg mL -1 Ba GT, 200 mM L-glutamine, 2 M ethylamine, and a reaction time of 5 h. The V319A/S437 G mutant was shown to increase the percentage yield of L-theanine from 58% to 83%. These results indicate the great potential of V319A/S437 G in L-theanine production after further study.
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Food Chemistry-X
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2023
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IF 6.1
Jialin Wu,Guangqun Lan,Na He,Laping He,Cuiqin Li,Xiao Wang,Xuefeng Zeng
A producing-fibrinolytic enzyme strain was isolated with high yield. The strain was identified as Bacillus amyloliquefaciens . B. amyloliquefaciens GUTU06 fibrinolytic enzyme was purified by acetone precipitation and reverse micelle. Acetone precipitation condition and reverse micelle condition were examined. Results showed that the total reverse micelle extraction efficiency was 64.49 % ± 1.6 %. The purification fold of the entire process reached 13.38. The optimum pH of purified enzyme is 5, and the optimum temperature is 45 °C. Fe 3+ and K + can enhance the fibrinolytic activity of the enzyme. Compared to commercial fibrinolytic enzymes such as urokinase and lumbrukinase, GUTU06 fibrinolytic enzymes have a lower pH optimal range and higher temperature stability. The molecular weight of the enzyme was approximately 28 kDa. Reverse micelle extraction with cetyl trimethylammonium bromide as a surfactant combined with acetone precipitation is suitable for separating and purifying fibrinolytic enzymes and a promising technique for obtaining active proteins.
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JOURNAL OF BIOSCIENCE AND BIOENGINEERING
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2017
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IF 2.24
Jie Sun,Liang Chen,Bo Lou,Yanbing Bai,Xinjun Yu,Man Zhao,Zhao Wang
Sucralose is a non-nutritive artificial sweetener used in a broad range of foods and beverages. In the present study, Bacillus amyloliquefaciens WZS01 was isolated, identified, and used as a catalyst both in regioselective acylation and deacetylation for sucralose preparation. Bacterial cells were immobilized on polyurethane foam and utilized to synthesize sucrose-6-acetate regioselectively. The yield of sucrose-6-acetate was >95% with 60 mM sucrose after 22 h of reaction. Free cells could hydrolyze 75 mM sucralose-6-acetate to produce sucralose with >99% yield after 24 h of reaction. B. amyloliquefaciens WZS01 could be considered a potential biocatalyst for sucralose preparation.
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LWT-FOOD SCIENCE AND TECHNOLOGY
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2019
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IF 3.714
Yali Jiang,Yu Lu,Youyi Huang,Shouwen Chen,Zhixia Ji
Caffeine is a major component of tea and coffee. Apart from the stimulatory effects, cumulative intake of caffeine has caused several diseases. In addition, the presence of caffeine brings out the deterioration of environmental pollution. Therefore, the demand for decaffeinated products, especially decaffeinated coffee and tea, is increasing. However, Pseudomonas putida as the most widely studied bacteria isn't suitable for producing decaffeinated tea and coffee due to the production of an unpleasant odor and endotoxins at the same time. A more appropriate system ( Bacillus amyloliquefaciens HZ-12: ndmABCDE ) is needed to produce decaffeinated products; and HZ-12: ndmABCDE was constructed by orderly integrating N -demethylase genes ( ndmABCDE ) in a safer strain HZ-12. Demethylases (NdmABCDE) in P. putida can degrade caffeine to xanthine, which was further degraded to CO 2 and NH 4 + by the purine metabolic pathway. Finally, HZ-12: ndmABCDE could degrade 52.6% of caffeine in the optimized medium, 31.5% higher than HZ-12; caffeine was demethylated in sequence to form theobromine, paraxanthine, 7-methylxanthine and xanthine; and there are no endotoxins and unpleasant odor. This study provides a safer strain (HZ-12: ndmABCDE ) for producing decaffeinated tea and coffee and a new idea that B. amyloliquefaciens HZ-12 can heterologously express the demethylase genes in P. putida .
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APPLIED MICROBIOLOGY AND BIOTECHNOLOGY
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2019
·Vol. 103
·期 13
·5367-5377
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IF 3.67
Ding Lianshuai,Guo Wenbin,Chen Xinhua
The bacterium, Bacillus amyloliquefaciens Pc3, was previously isolated from Antarctic seawater and has been found to show antagonistic activity against the fungus, Rhizoctonia solani ACCC 36316, which causes a severe disease known as Sclerotinia sclerotiorum in rapeseed plants. Bacillus lipopeptides had been widely used as biocontrol agents for plant diseases. In this study, we isolated 11 lipopeptide compounds from B. amyloliquefaciens Pc3 culture broth via reversed-phase high-performance liquid chromatography (RP-HPLC) and used matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) to identify these as iturin A (C 14 , C 15 , C 16 , C 17 ), fengycin B (C 14 , C 15 , C 16 , C 17 ), and surfactin (C 14 , C 15 , C 16 ). We further found that the addition of exogenous alkanoic acids, including myristic acid, pentadecanoic acid, palmitic acid, heptadecanoic acid, octadecanoic acid, and nonadecanoic acid, to the bacterial growth media could promote lipopeptide production and enhance the antifungal activities of crude lipopeptide extracts from B. amyloliquefaciens Pc3. In addition, the transcriptional levels of three lipopeptide synthesis genes, ituD , fenA , and srfA-A , and two fatty acid metabolism–related genes, FabI , which encodes enoyl-ACP reductase, and FadB , which encodes enoyl-CoA hydratase, were found to be upregulated in cells grown with exogenous alkanoic acids. Among the six alkanoic acids tested, those with odd carbon chain lengths had a greater effect on lipopeptide production, antifungal activity, and target gene upregulation than those with even carbon chain lengths. These results provide a practical approach for the efficient production of lipopeptides in Bacillus amyloliquefaciens Pc3.
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ACS Synthetic Biology
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2026
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IF 4.5
Qian Zhong,Zhen Li,Waibin Duan,Peng Lei,Xiaoqi Xu,Hong Xu,Sha Li,Yibin Qiu
Dynamic metabolic regulation facilitates real-time sensing of pathway states and precise redirection of metabolic flux, thereby enhancing the biosynthesis of diverse value-added compounds. Here, we designed an autoinducible molecular switch in Bacillus amyloliquefaciens by integrating a Pantoea alhagi-derived PaSspB-ssrA* proteolytic system with the DegU-RapG-PhrG quorum-sensing (QS) module. The OFF module employs the novel PaSspB-ssrA* system for targeted degradation of ssrA*-tagged proteins with 86% efficiency, and the ON module utilizes a DegU-activated PispA promoter for cell density-dependent gene expression. To improve hyaluronic acid (HA) production and reduce byproduct accumulation, this system was applied by fusing ssrA* tags into the glycolysis-critical genes pfkA and fruA to attenuate glycolytic flux, together with QS-regulated coexpression of PaSspB and SthHL in engineered Δldh/ΔwbpA/ΔnagB strains, achieving 13.5 ± 0.19 g/L of low-molecular-weight HA (2.89 × 104 Da). The autonomous, inducer-free platform enables cost-effective HA biosynthesis in B. amyloliquefaciens, with broad applicability for synthesizing high-value bioproducts.
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LWT-FOOD SCIENCE AND TECHNOLOGY
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2018
·
IF 3.129
Zhen Qin,Sa Luo,Yun Li,Qiming Chen,Yongjun Qiu,Liming Zhao,Lihua Jiang,Jiachun Zhou
Chitooligosaccharides are widely used in functional food, medicaments and agriculture. Controllable conversion of chitosan to chitooligosaccharides with desired degree of polymerization (DP) is of great value. Herein, a novel glycoside hydrolase family 46 chitosanase (BaCsn46A) was cloned and expressed from Bacillus amyloliquefaciens. BaCsn46A exhibited good enzymatic properties with high specific activity (1031.2 U/mg) under optimal hydrolysis conditions of pH 6.0 and 50 °C. BaCsn46A is an endo-type chitosanase, which could be utilized to yield abundant chitooligosaccharides. Furthermore, the preparation of high degree of polymerization chitooligosaccharides (DP 5–10) was investigated by BaCsn46A in an enzymatic reactor with a subsequent series of membranes. The maximum concentration of total chitooligosaccharides (DP 2–10) was 28.11 g/L (93.70% yield). The proportion of high degree of polymerization chitooligosaccharides (DP 5–10) occupied 56.17% (w/w) of total chitooligosaccharides. This study provided a cleaner production process for the controllable preparation of chitooligosaccharides with specific degree of polymerization.
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CATALYSIS COMMUNICATIONS
·
2014
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IF 3.32
Jian-yong Zheng,Yu-qiang Wang,Wei-feng Luo,Sha-sha Zhou,Qing Zhu,Xiang-xian Ying,Zhao Wang
A new esterase-producing strain ( Bacillus amyloliquefaciens WZZ002) that exhibits high hydrolytic activity, excellent enantioselectivity, and high substrate tolerance on Boc- dl -Alanine methyl ester was isolated from soil samples. The reaction temperature, pH, and neutralizer optima of the cell-mediated biocatalysis were 35 °C, pH 8.0, and NH 3 ·H 2 O, respectively. The optimal substrate concentration was 2 M, with a biocatalyst loading of 50 g/L. Results showed that the enantiomeric excess values of substrate and product were both greater than 99%. Thus, bioprocessing with the use of the isolated strain is a promising route for the commercial production of Boc- d -Ala-OMe.
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Journal of Functional Foods
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2020
·
IF 3.701
Jia-hua Kuang,Yan-yan Huang,Jin-shuang Hu,Jia-jia Yu,Qin-yu Zhou,Dong-mei Liu
Accumulating evidences have reported that polysaccharide could alleviate colitis through the maintenance of intestinal homeostasis. In this study, an exopolysaccharide (EPS-K4) from Bacillus amyloliquefaciens was obtained via anionic-exchange chromatography which was with an average molecular weight of 10,067 Da and consisted of mannose, rhamnose, glucuronic acid, and glucose with a molar ratio of 40.09:23.65:11.42:17.68. Furthermore, administration of EPS-K4 relieved symptoms in colitis mice via gut microbiota modulation. The levels of pathogenic bacteria, such as Enterococcus and Escherichia - Shigella , were significantly suppressed. In contrast, the levels of Lactobacillus and intestinal microbiota diversity were increased. EPS-K4 could stimulate mucin secretion to maintain the integrity of the gut barrier and decrease the levels of virulent substances (endotoxin, diamine oxidase, and D-lactic acid) in serum. The pro-inflammatory cytokines (TNF-α) in serum were reduced, conversely, anti-inflammatory cytokines (IL-10) were increased. These findings indicated the possibility of EPS-K4 as a chemotherapy candidate for the prevention of colitis.
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Microbial Cell Factories
·
2022
·Vol. 21
·期 1
·1-13
·
IF 6.352
Xin Qinglong,Chen Yudan,Chen Qianlin,Wang Bin,Pan Li
Background Bacillus amyloliquefaciens is generally recognized as food safe (GRAS) microbial host and important enzyme-producing strain in the industry. B.amyloliquefaciens LB1ba02 is a production strain suitable for secreting mesophilic α-amylase in the industry. Nevertheless, due to the low transformation efficiency and restriction-modification system, the development of its CRISPR tool lags far behind other species and strains from the genus Bacillus . This work was undertaken to develop a fast and efficient gene-editing tool in B.amyloliquefaciens LB1ba02. Results In this study, we fused the nuclease-deficient mutant Cas9n (D10A) of Cas9 with activation-induced cytidine deaminase (AID) and developed a fast and efficient base editing system for the first time in B. amyloliquefaciens LB1ba02. The system was verified by inactivating the pyrF gene coding orotidine 5'-phosphate decarboxylase and the mutant could grow normally on M9 medium supplemented with 5-fluoroorotic acid (5-FOA) and uridine (U). Our base editing system has a 6nt editing window consisting of an all-in-one temperature-sensitive plasmid that facilitates multiple rounds of genome engineering in B. amyloliquefaciens LB1ba02. The total editing efficiency of this method reached 100% and it achieved simultaneous editing of three loci with an efficiency of 53.3%. In addition, based on the base editing CRISPR/Cas9n-AID system, we also developed a single plasmid CRISPR/Cas9n system suitable for rapid gene knockout and integration. The knockout efficiency for a single gene reached 93%. Finally, we generated 4 genes ( aprE , nprE , wprA , and bamHIR ) mutant strain, LB1ba02△4. The mutant strain secreted 1.25-fold more α-amylase into the medium than the wild-type strain. Conclusions The CRISPR/Cas9n-AID and CRISPR/Cas9n systems developed in this work proved to be a fast and efficient genetic manipulation tool in a restriction-modification system and poorly transformable strain.
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JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
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2022
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IF 5.895
Jinfang Zhang,Baoyue Zhu,Xiaojian Xu,Yihan Liu,Qinggang Li,Yu Li,Fuping Lu
Bacillus amyloliquefaciens has great potential as a host for heterologous protein production, but its severe autolytic behavior has precluded its industrial application to date. Because d,l-endopeptidase activity-guided cell wall rigidity is considered essential for autolysis resistance, we investigated the effects of d,l-endopeptidase genes lytE, lytF, cwlO, and cwlS play on the growth, lysis, and morphology remodeling of B. amyloliquefaciens strain TCCC11018. Individual and combinatorial deletion of lytE, lytF, and cwlS enhanced the cell growth and delayed cell lysis. For the best mutant with the lytF and cwlS double deletion, the viable cell number at 24 h increased by 11.90% and the cell wall thickness at 6 h increased by 25.87%. Transcriptomic and proteomic analyses indicated that the improvement was caused by enhanced peptidoglycan synthesis. With the lytF and cwlS double deletion, the extracellular green fluorescent protein and phospholipase D expression levels increased by 113 and 55.89%, respectively. This work broadens our understanding of the relationship between d,l-endopeptidases and B. amyloliquefaciens cell characteristics, which provides an effective strategy to improve the heterologous protein expression in B. amyloliquefaciens-based cell factories.
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