JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
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2024
·
IF 5.7
Jiawei Zhou,Yumin Sang,Zhuang Wang,Jiacheng Feng,Linjiang Zhu,Xiaolong Chen
Enzymatic kinetic resolution is a promising way to produce l-menthol. However, the properties of the reported biocatalysts are still unsatisfactory and far from being ready for industrial application. Herein, a para-nitrobenzylesterase (pnbA) gene from Bacillus subtilis was cloned and expressed to produce l-menthol from d,l-menthyl acetate. The highest enantiomeric excess (ee) value of the product generated by pnbA was only approximately 80%, with a high conversion rate (47.8%) of d,l-menthyl acetate with the help of a cosolvent, indicating high catalytic activity but low enantioselectivity (E = 19.95). To enhance the enantioselectivity and catalytic efficiency of pnbA to d,l-menthyl acetate in an organic solvent-free system, site-directed mutagenesis was performed based on the results of molecular docking. The F314E/F315T mutant showed the best catalytic properties (E = 36.25) for d,l-menthyl acetate, with 92.11% ee and 30.58% conversion of d,l-menthyl acetate. To further improve the properties of pnbA, additional mutants were constructed based on the structure-guided triple-code saturation mutagenesis strategy. Finally, four mutants were screened for the best enantioselectivity (ee > 99%, E > 300) and catalytic efficiency at a high substrate concentration (200 g/L) without a cosolvent. This work provides several generally applicable biocatalysts for the industrial production of l-menthol.
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FOOD MICROBIOLOGY
·
2024
·
IF 4.5
Yali Li,Tianqi Wangjiang,Zhida Sun,Liu Shi,Sheng Chen,Lang Chen,Xiaojia Guo,Wenjin Wu,Guangquan Xiong,Lan Wang
Aeromonas veronii is associated with food spoilage and some human diseases, such as diarrhea, gastroenteritis, hemorrhagic septicemia or asymptomatic and even death. This research investigated the mechanism of the growth, biofilm formation, virulence, stress resistance, and spoilage potential of Bacillus subtilis lipopeptide against Aeromonas veronii . Lipopeptides suppressed the transmembrane transport of Aeromonas veronii by changing the cell membrane's permeability, the structure of membrane proteins, and Na + /K + -ATPase. Lipopeptide significantly reduced the activities of succinate dehydrogenase (SDH) and malate dehydrogenase (MDH) by 86.03% and 56.12%, respectively, ultimately slowing Aeromonas veronii growth. Lipopeptides also restrained biofilm formation by inhibiting Aeromonas veronii motivation and extracellular polysaccharide secretion. Lipopeptides downregulated gene transcriptional levels related to the virulence and stress tolerance of Aeromonas veronii . Furthermore, lipopeptides treatment resulted in a considerable decrease in the extracellular protease activity of Aeromonas veronii , which restrained the decomposing of channel catfish flesh. This research provides new insights into lipopeptides for controlling Aeromonas veronii and improving food safety.
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Foods
·
2024
·Vol. 13
·期 17
·2731
·
IF 4.7
Qibo Tan,Yongjun Wu,Cen Li,Jing Jin,Lincheng Zhang,Shuoqiu Tong,Zhaofeng Chen,Li Ran,Lu Huang,Zeyan Zuo
Fermented soybeans are popular among many for their rich soy sauce-like aroma. However, the precise composition of this aroma remains elusive, with key aroma compounds unidentified. In this study, we screened the candidate genesilvAandserAin BJ3-2 based on previous multi-omics data, and we constructed three mutant strains, BJ3-2-ΔserA, BJ3-2-ΔilvA, and BJ3-2-ΔserAΔilvA, using homologous recombination to fermented soybeans with varying intensities of soy sauce-like aroma. Our objective was to analyze samples that exhibited different aroma intensities resulting from the fermented soybeans of BJ3-2 and its mutant strains, thereby exploring the key flavor compounds influencing soy sauce-like aroma as well analyzing the effects ofilvAandserAon soy sauce-like aroma. We employed quantitative descriptive sensory analysis (QDA), gas chromatography–olfactometry–mass spectrometry (GC-O-MS), relative odor activity value analysis (rOAV), principal component analysis (PCA), orthogonal partial least squares-discriminant analysis (OPLS-DA), and partial least squares regression analysis (PLSR). QDA revealed the predominant soy sauce-like aroma profile of roasted and smoky aromas. GC-MS detected 99 volatile components, predominantly pyrazines and ketones, across the four samples, each showing varying concentrations. Based on rOAV (>1) and GC-O, 12 compounds emerged as primary contributors to soy sauce-like aroma. PCA and OPLS-DA were instrumental in discerning aroma differences among the samples, identifying five compounds with VIP > 1 as key marker compounds influencing soy sauce-like aroma intensity levels. Differential analyses of key aroma compounds indicated that the mutant strains ofilvAandserAaffected soy sauce-like aroma mainly by affecting pyrazines. PLSR analysis indicated that roasted and smoky aromas were the two most important sensory attributes of soy sauce-like aroma, with pyrazines associated with roasted aroma and guaiacol associated with smoky aroma. In addition, substances positively correlated with the intensity of soy sauce-like aroma were verified by additional experiments. This study enhances our understanding of the characteristic flavor compounds in soy sauce-like aroma ferments, provides new perspectives for analyzing the molecular mechanisms of soy sauce-like aroma formation, and provides a theoretical framework for the targeted enhancement of soy sauce-like aroma in various foods.
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Chemical and Biological Technologies in Agriculture
·
2024
·Vol. 11
·期 1
·1-15
·
IF 5.2
You Yuxin,Wang Chen,Abdallah Yasmine,Liu Quanhong,Liu Chentao,Luo Jinyan,Dai Dejiang,Al-Rejaie Salim S.,Mohany Mohamed,Li Bin,Ogunyemi Solabomi Olaitan,An Qianli
One-pot synthesis of metal nanoparticles under ambient temperature and pressure using reducing and stabilizing materials from microbes is energy-effective and ecofriendly, but upstream extraction of biological raw materials and downstream purification of nanoparticles from bioreactors are laborious and expensive. To simplify the productive process for using metal nanoparticles as microbicides to control plant pathogens, we use an endospore-forming Bacillus biocontrol agent to produce the nano-microbicide and use the bacterial raw materials as bio-microbicides together with the nano-microbicide.Bacillus cells at the stationary phase form endospores and tolerate Ag+ and Ag nanoparticles (AgNPs), while the cell-free culture supernatant (CFCS) mediates the synthesis of AgNPs. AgNPs produced from the Bacillus culture and CFCS show similar physical, chemical, and electrical characteristics, and bactericidal and anti-biofilm activities. Moreover, the diluted products effectively protect the kiwifruit leaves from the infection of the pathogen Pseudomonas syringae pv. actinidiae.This coproduction of bio-microbicide and nano-microbicide is a totally green one-pot synthesis process without extraction and purification and without production of waste and can be easily scaled up using the existing fermentation processing of Bacillus biocontrol agents. The application of the synergistic bio-microbicide and nano-microbicide can effectively control the bacterial canker disease of kiwifruit plants.
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FOOD CONTROL
·
2024
·
IF 5.6
Yanmei Li,Lun Luo,Wenhai Wang,Bin Hong,Yi Ma,Jufang Wang
Synergistic antibacterial effect as a promising strategy against foodborne pathogens is compelling since the development of novel antibacterial agents is not so easy. Here we investigated the synergistic effect of cell wall hydrolase Lys14579 and cinnamaldehyde (CAL) against emetic Bacillus cereus . The MICs of Lys14579 and CAL against emetic B. cereus were 25 and 200 μg/mL, respectively. The combination of Lys14579 and CAL displayed a synergistic antimicrobial effect with a Fractional Inhibitory Concentration Index (FICI) of 0.375. Bactericidal assays revealed that this combination had better bactericidal performance than either substance alone. Furthermore, the combination of Lys14579 and CAL effectively inhibited the biofilm formation of emetic B. cereus at the concentrations of 6.25 and 50 μg/mL, respectively. Additionally, it down-regulated the cereulide synthetase gene ( cesB ) expression at the transcription level and reduced swarming motility by 55%. Scanning electron microscope and PI uptake assays further demonstrated that the combination accelerated the disruption of emetic B. cereus cells. Finally, the synergistic preservative effect of this combinational was observed in boiled rice and fresh lean beef. Thus, the combination of Lys14579 and CAL represents a potential synergistic strategy for controlling emetic B. cereus contamination in the food industry.
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Plants-Basel
·
2025
·Vol. 14
·期 18
·2918
·
IF 4.1
Guannan Kong,Da Song,Chao Zhang,Xinyao Jia,Yingying Ren,Shuhe Wei,Huiping Dai
Cadmium contamination in soil threatens ecological safety and human health. Phytoremediation has gained attention due to its cost-effectiveness and environmental sustainability. Studies show that plant growth-promoting rhizobacteria can enhance the ability of hyperaccumulator plants to remove heavy metals. This research aimed to isolate and identify plant-growth-promoting rhizobacteria under Cd stress and assess their impact on the growth and Cd accumulation ofSolanum nigrumL. Six bacterial strains were isolated from the rhizosphere ofS. nigrum, all showing high Cd tolerance. Among them, LKT25 exhibited multiple growth-promoting traits, including indole-3-acetic acid production, nitrogen fixation, 1-aminocyclopropane-1-carboxylate deaminase, and siderophore synthesis. Under varying Cd concentrations (5, 25, and 50 mg/kg), theBacillus thuringiensisstrain LKT25 significantly improved Cd removal byS. nigrum. At 5 mg/kg Cd, the removal efficiency reached 45.13%. LKT25 also enhanced plant growth, photosynthesis, and antioxidant activity, contributing to improved Cd remediation. This study provides new microbial resources and technical support for using rhizobacteria in remediating heavy metal-contaminated soils.
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BIODEGRADATION
·
2025
·Vol. 36
·期 3
·1-18
·
IF 3.2
Rajasekar Adharsh,Zhao Cailin,Wu Suowei,Murava Raphinos Tackmore,Norgbey Eyram,Omoregie Armstrong Ighodalo,Moy Charles K. S.
Heavy metal pollution in urban freshwater, driven by anthropogenic activities, poses significant risks to aquatic ecosystems and human health due to its toxicity and persistence. Recently, urease-producing bacteria have gained attention for their ability to remove heavy metals through microbial-induced carbonate precipitation (MICP). In this study, eight urease-producing bacteria were exposed to individual solutions of zinc (Zn 2+ ), cadmium (Cd 2+ ), and nickel (Ni 2+ ) at concentrations ranging from 0 to 6 mM to assess their resistance. Three strains— Bacillus subtilis HMZC1 (B2), Bacillus sp. HMZCSW (B6), and Comamonas sp. HMZC (B11)—survived at 4 mM and 6 mM, while most others could not tolerate 4 mM. Their urea-degrading ability was tested at different pH levels, identifying an optimal pH of 7 for MICP. Heavy metal carbonate precipitation experiments at 4 mM and 6 mM revealed that all three strains achieved > 93% removal of Zn 2+ , Ni 2+ , and Cd 2+ within 72 h. Comamonas sp. HMZC exhibited the highest efficiency, achieving > 95% removal of certain heavy metals at 6 mM. Statistical analysis using one-way ANOVA revealed significant differences (p < 0.05) in heavy metal removal efficiencies among the strains for certain treatment conditions (Cd 2+ and Zn 2+ at 4 mM), although not all comparisons reached statistical significance. Scanning Electron Microscopy and X-ray Diffraction confirmed the morphology and composition of the precipitated heavy metal carbonates. Our findings demonstrate that urease-producing bacteria can effectively immobilize multiple heavy metals, highlighting the MICP process as a practical and sustainable biological approach for ecological restoration and wastewater treatment.
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Microorganisms
·
2025
·Vol. 13
·期 7
·1698
·
IF 4.2
Yue Cheng,Qian Fu,Junjia Xu,Xinhua Niu,Lin Liu,Jiaqi Wang,Jingwen Quan,Qingyue Yu,Baoyan Chi,Haitao Li,Rongmei Liu
Prometryn and acetochlor are herbicides used to control weeds in farmlands and other areas. They enter the soil through direct application, residual accumulation in crops, and atmospheric deposition. The pollution of their residues in the environment has attracted people’s attention. Bioremediation is one of the main methods to solve such problems. In this study, the effects of prometryn and acetochlor-degrading strain NM-1 on soil enzymes, soil microbial communities, and physiological indexes of soybean seedlings during soil remediation were studied, and the relationship between them was discussed. The results showed that 81.54% of prometryn (50 mg·L−1) and 89.47% of acetochlor (50 mg·L−1) were degraded within 15 days after NM-1 inoculation in soil. NM-1 positively affected soil enzyme activities and soil microbial communities, and the abundance of beneficial bacteria in soil increased. More importantly, the inoculation of strain NM-1 under prometryn and acetochlor stress significantly increased plant height, root length, root volume, water content, chlorophyll concentration, and root activity of soybean. The results of these studies showed that the NM-1 strain showed significant potential in bioremediation in order to provide technical support for solving the problem of prometryn and acetochlor pollution.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2019
·
IF 4.784
Zhanghui Gu,Jiangli Lai,Jiahao Hang,Chunguang Zhang,Shujun Wang,Yuliang Jiao,Shu Liu,Yaowei Fang
If natural proteases are used in organic synthesis, they are often inactivated or give a low rate of reaction in non-aqueous or aqueous-organic media. Therefore, to reveal the molecular mechanism governing the stability of proteases in organic solvents and increase protease stability in those systems is of intriguing interest. In the present study, the activity and conformational changes of an organic solvent-stable protease (OSP) from Bacillus sphaericus DS11 in different concentrations of methanol were investigated by measuring fluorescence, UV–Vis spectra, circular dichroism (CD), and conducting molecular dynamics (MD) simulations. The OSP expanded with increasing methanol concentration. The methanol molecules were able to enter into the OSP, leading to microenvironmental changes around the aromatic amino acids . More hydrophobic groups were exposed to the solvents at high methanol concentrations, and the original hydrophobic interaction in the protein decreased, thus resulting in the secondary and tertiary structure change in the OSP. Our results provide helpful insight into the molecular mechanism of the OSP tolerance to organic solvent and indicate directions for future work to design and engineer proteases that are stable at high organic solvent concentrations.
研究领域:
生物化学
·
蛋白质工程
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Scientific Reports
·
2017
·Vol. 7
·期 1
·1-15
·
IF 4.259
Tahir Hafiz Abdul Samad,Gu Qin,Wu Huijun,Niu Yuedi,Huo Rong,Gao Xuewen
Volatile organic compounds (VOCs) produced by various bacteria have significant potential to enhance plant growth and to control phytopathogens. Six of the most effective antagonistic Bacillus spp. were used in this study against Ralstonia solanacearum (Rsc) TBBS1, the causal agent of bacterial wilt disease in tobacco. Bacillus amyloliquefaciens FZB42 and Bacillus artrophaeus LSSC22 had the strongest inhibitory effect against Rsc . Thirteen VOCs produced by FZB42 and 10 by LSSC22 were identified using gas chromatography-mass spectrometry analysis. Benzaldehyde, 1,2-benzisothiazol-3(2 H)-one and 1,3-butadiene significantly inhibited the colony size, cell viability, and motility of pathogens and negatively influenced chemotaxis. Transmission and scanning electron microscopy revealed severe morphological and ultra-structural changes in cells of Rsc. Furthermore, VOCs altered the transcriptional expression level of PhcA (a global virulence regulator), type III secretion system (T3SS), type IV secretion system (T4SS), extracellular polysaccharides and chemotaxis-related genes, which are major contributors to pathogenicity, resulting in decreased wilt disease. The VOCs significantly up-regulated the expression of genes related to wilt resistance and pathogen defense. Over-expression of EDS1 and NPR1 suggest the involvement of SA pathway in induction of systemic resistance. Our findings provide new insights regarding the potential of antibacterial VOCs as a biocontrol tool against bacterial wilt diseases.
研究领域:
植物病理学
·
微生物学
·
分子生物学
·
农业科学
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Advanced Science
·
2026
·
IF 14.1
Baocai Zhang,Chunxiao Qiao,Huichun Liu,Yiyun Wang,Yan Liu,Huan Yu,Junqi Zhang,Chao Li,Deguang Wu,Qulai Tang,Zhiwen Wang,Danni Zhang,Dake Xu,Feng Li,Hao Song
The rapid proliferation of lithium-ion batteries (LIBs) underscores the need for recycling, yet existing methods are costly, inefficient, and environmentally challenging. This work developed a spent LIBs recycling approach using brewing wastewater and designed a microbial consortium as a biocatalyst for facilitating metal oxide leaching. The Shewanella oneidensis reduces spent LIBs cathode LiNi x Co y Mn 1-x-y O 2 (NCM) via extracellular electron transfer (EET) by feeding with brewing wastewater's organics, and the Bacillus subtilis removes residual ethanol to eliminate inhibition on EET. The catalytic performance is further enhanced via boosting EET, increasing metal oxide leaching, which, however, impairs cell viability. To bolster resistance, the global transcriptional factor IrrE is introduced, achieving a leached metal ion concentration of 102.4 mg L −1 , 30.12 times higher than in brewing wastewater. Cellular electrophysiology analyses reveal that S. oneidensis utilizes c -type cytochromes MtrC and OmcA, and riboflavin to transfer electrons to NCM. This study proposes a sustainable “treating waste with waste” technology for recycling spent LIBs.
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Food Bioscience
·
2026
·
IF 6.2
Wei Tao,Xinyu Shan,Said Nawab,Zhangchenyu Ni,Elvis Kwame Adinkra,Mingyu Guo,Yifeng Jiang,Yu Chen,Chuanchao Wu,Yan Liu
Menaquinone-7 (MK-7), a subtype of Vitamin K 2 , is in high demand within the healthcare sector due to its health benefits. This study proposes a two-stage fermentation strategy combining submerged fermentation with leakage fermentation to enhance MK-7 production in a Bacillus subtilis mutant strain and preliminarily reveal its potential metabolic mechanisms. The Results showed that this strategy achieved a total MK-7 yield of 163.56 mg/L, representing an 85.48% increase over conventional biofilm fermentation, among which extracellular MK-7 production was significantly increased by 269.65%. Results from scanning electron microscopy, fluorescence microscopy, and flow cytometry confirmed that the enhanced MK-7 production was closely associated with increased membrane permeability induced by Brij-58. Furthermore, integrating gas chromatography–ion mobility spectrometry (GC-IMS) and untargeted metabolomics analyses revealed that the highly active central carbon metabolism in the first stage promoted cell growth and MK-7 precursor accumulation, while the possible diversion of carbon flux to secondary metabolic pathways in the second stage facilitated efficient MK-7 biosynthesis. Meanwhile, it was found that the increase in membrane permeability might be attributed to oxidative stress induced by Brij-58, thereby facilitating the efflux of intracellular metabolites and effectively alleviating excessive intracellular MK-7 accumulation. These findings could serve as a potential industrial reference for future process optimization and scale-up validation of MK-7 fermentation, while also offering useful insights for addressing yield bottlenecks in other microbial metabolites.
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