JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE
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2021
·Vol. 101
·期 13
·5645-5651
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IF 3.639
Linzi Yang,Xueli Li,Yunhao Lu,Yuanping Lv,Yuanlong Chi,Qiang He
BACKGROUND Esters are indispensable aroma compounds and contribute significantly to the fruity aromas in fermented condiments. The ester synthesis activity and pathways of Bacillus licheniformis , Candida etchellsii, and Zygosaccharomyces rouxii, isolated from Chinese horse bean chili-paste (CHCP), were investigated. Chemical buffer models containing esterification and alcoholysis systems inoculated with extracellular extracts of these three strains were established. RESULTS The ester synthesis activity of C. etchellsii was stronger than that of the other two strains. Zygosaccharomyces rouxii could synthesize acetate esters via esterification, whereas the biosynthesis pathways of B. licheniformis and C. etchellsii were esterification and alcoholysis. Esterification exhibited relatively high activity at pH 4, whereas alcoholysis activity improved with an increase in the pH from 4 to 8. Candida etchellsii could synthesize C 6 –C 8 of acetate esters, and its activity improved with the number of alcohol carbon atoms. These three strains could synthesize C 10 –C 18 of ethyl esters. Their ethyl ester synthesis activity decreased with the aliphatic acid carbon number. CONCLUSION Candida etchellsii has the potential to be used in CHCP fermentation to accumulate esters and improve flavor compared with the other two strains. This research is helpful in explaining the mechanism of ester synthesis in fermented condiments. © 2021 Society of Chemical Industry.
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BIOTECHNOLOGY LETTERS
·
2021
·Vol. 43
·期 3
·677-690
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IF 2.461
Zhang Chaolei,Wang Chao,Zhao Shan,Xiu Zhilong
Objectives Probiotics ( Bacillus subtilis 04178) were entrapped in alginate-chitosan microcapsules by high-voltage electrostatic process. The encapsulation pattern was established as entrapped low density cells with culture (ELDC wc ). The performance of ELDC wc cells was investigated against stress environments of simulated digestive fluids. Results After incubation in simulated gastric (pH 2.5) and intestinal fluids (4% bile salt) for 2 h, the survival rate of ELDC wc cells (18.19% and 27.54%) was significantly higher than that of the free cells (0.0000009% and 0.0005%). The reason why B. subtilis embedded in microcapsules can resist the stress environments was that the mass production of extracellular proteins and polysaccharides prompted B. subtilis to form cell aggregates. The production of extracellular proteins and polysaccharides were regulated by the concentration of c-di-GMP and the expression of ydaJKLMN operon, abbA , sinI , slrA , slrB , abrR and sinR . Conclusions c-di-GMP is important for the production of extracellular polymer substance to enhance probiotic viability in stress environments.
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ANALYST
·
2020
·Vol. 145
·期 9
·3257-3265
·
IF 3.978
Yue Li,Xinxin Xu,Liqiang Liu,Hua Kuang,Liguang Xu,Chuanlai Xu
In this study, a gold immunochromatographic assay (GICA) based on a penicillin receptor protein (PBP) is proposed to simultaneously detect penicillin, cephalosporin, and carbapenem antibiotics in milk and chicken. A mutant PBP, carboxy-terminal of the β-lactam sensor-transducer protein (BlaR-CTD, I188KS19CG24C) from Bacillus licheniformis ATCC14580 was expressed in E. coli as a soluble His-tag fusion protein. The purified BlaR-CTD mutant was labeled with colloidal gold (CG-BlaR-CTD-M) and applied to develop GICA. The GICA method was performed based on a competitive form, where the binding of the ampicillin-bovine serum albumin conjugate (Amp-BSA) to CG-BlaR-CTD-M was inhibited by free β-lactams in samples. The performance of the assay was confirmed by analysis of milk and chicken samples. The limits of detection of 21 β-lactam antibiotics met the maximum residue limits set by the European Union and China. The GICA gave results within 10 min, thus providing a rapid and reliable method for the on-site detection of multiple β-lactams in milk and chicken samples.
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TALANTA
·
2023
·
IF 6.1
Jiaqi Dang,Min Li,Wenhui Fang,Ying Wu,Shixian Xin,Yutao Cao,Hong Zhao
The abnormal concentration of anthrax spore biomarker 2,6-pyridinedicarboxylic acid (2,6-DPA) will seriously affect public health. Therefore, a sensitive and rapid assay for 2,6-DPA monitoring is of vital importance. In this work, novel nano-sized amorphous Eu-NH 2 BDC (amEu-NH 2 BDC) and amorphous Tb-NH 2 BDC (amTb-NH 2 BDC) metal organic frameworks are prepared by adjusting the ratio of metal and ligand, respectively. Both of them exhibit highly sensitive and selective ratiometric fluorescence detection for 2,6-DPA with wider linear range and lower detection limit in aqueous solutions and human serum. Attributed to the coordination effect of 2,6-DPA in triggering the characteristic fluorescence emissions of Eu 3+ or Tb 3+ by replacing coordinated solvent molecules, as evidenced by ultraviolet–visible spectroscopy, the fluorescence lifetimes analysis, thermal gravimetric analysis , Fourier-transform infrared spectroscopy, density functional theory (DFT) simulations and X-ray photoelectron spectroscopy. In addition, the amEu-NH 2 BDC or amTb-NH 2 BDC loaded paper-based microsensors are constructed for real-time and sensitive detection of 2,6-DPA and coupled with a smartphone-assisted visual portable device.
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Food Bioscience
·
2023
·
IF 5.2
Kaiyong Yao,Qile Xia,Yan Cao,Bindan Chen,Jie Cai,Chenxing Liu
Yellow wine lees (YWL) are the main byproduct in the yellow wine brewing and can be used as animal feed. The deficiencies in fiber digestibility and amino acid equilibrium of YWL limited its utility value in animal feeding. The nutritional profile of YWL could be moderated after fermentation treatment. We fermented YWL with Candida utilis KF01 and Bacillus subtilis KF02, whose genomes were sequenced. We set three groups in the animal test with 15 Holstein cows : control, YWL, and fermented yellow wine lees (FYWL) group. 206 and 5 amino acid metabolism-related KEGG pathways, as well as 5257 (639 GO and 4618 eggNOG annotations) and 1579 (372 GO and 1207 eggNOG annotations) amino acid metabolism-related gene annotations were found in C. utilis KF01 and B. subtilis KF02. The collected milk samples were analyzed for composition. The contents of mono-unsaturated fatty acid (MUFA, 36.90% relative content), poly-unsaturated fatty acid (PUFA, 5.63% relative content), and essential amino acid (EAA, 2.01%) in the FYWL group milk were significantly (P < 0.05) higher. The content of flavor substances in the FYWL group (146.33 ng/mL) was the highest, followed by the control (89.19 ng/mL) and the YWL group (41.36 ng/mL). The principal component analysis (PCA) result presented the intra-group variations in flavor substances and differences in single substance among all groups. Feeding FYWL had significant effects (P < 0.05) in the Holstein cows on the milk composition.
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PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY
·
2023
·
IF 4.7
Jinsheng Xu,Lin Zheng,Mingtao Tan,Hongfei Wu,Shanchun Yan,Dun Jiang
Heavy metal pollution is an abiotic factor that can affect the efficiency of pest control. In this study, two microbial pesticides , Bacillus thuringiensis and Mamestra brassicae nuclear polyhedrosis virus (MbNPV), were used to treat Hyphantria cunea larvae with Cd pre-exposure, and the humoral and cellular immunity of H. cunea larvae with Cd exposure were evaluated. The results showed that Cd exposure increased the susceptibility of H. cunea larvae to microbial pesticides B. thuringiensis and MbNPV, and the lethal effect of Cd exposure and microbial pesticides on H. cunea larvae was synergistic. Cd exposure significantly decreased the expression of pathogen recognition genes (GNBP1 and GNBP3), signal transduction genes (Relish, Myd88, Tube, and Imd), and antimicrobial peptide gene (Lebocin) in the humoral immunity of H. cunea larvae compared with the untreated larvae. Parameters of cellular immunity, including the number of hemocytes , phagocytic activity , melanization activity, encapsulation activity, and the expression of three phagocytic regulatory genes (HEM1, GALE1, GALE2), were also found to decrease significantly in Cd-treated larvae. TOPSIS analysis showed that humoral immunity, cellular immunity, and total immunity levels of H. cunea larvae with Cd exposure were weaker than those in untreated larvae. Correlation analysis showed that the mortality of two microbial pesticides investigated in H. cunea larvae was negatively correlated with the humoral and cellular immunity of larvae. Taken togther, Cd exposure results in immunotoxic effects on H. cunea larvae and the use of microbial pesticides are an effective strategy for pest control in heavy metal-polluted areas.
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CHINESE CHEMICAL LETTERS
·
2018
·
IF 2.631
Rongqiao Chen,Chune Guo,Wubo Chu,Nan Jiang,He Li
Marine microorganism accumulated on the surface of ships or pipelines would accelerate fouling organisms, such as mussels and barnacles, adhered on the surface. It was significant to understand the bio-interaction between the microorganisms and the surface. Attenuated total reflection (ATR) Fourier transform infrared (FTIR) spectroscopy was used to study the initial stages of marine microorganism adhering to surfaces, because it could probe the microorganism interaction to the surface regardless of the water interference. Bacillus sp. and Escherichia coli were selected to study the initial attachment on different surfaces, because they were typical fouling microorganisms and showed opposite Gram stain results. The assays were conducted respectively in dried and settled bacteria on two different surfaces (ZnSe, Al 2 O 3 coated on ZnSe). IR spectra of settled bacteria showed amide I band red shift and amide II band blue shift in aqueous environment on both surfaces compared with the dry bacteria. The reasons of amide bands shift were investigated and it was discovered that the hydrogen bond between the water and the protein of the bacteria led to the protein secondary structure change. ATR-FTIR provided an approach to study the attachment process and showed dynamic changing process on the surface, and it could be an appropriate approach to study the interaction between proteins and chemicals.
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CHIRALITY
·
2018
·Vol. 30
·期 7
·907-912
·
IF 1.833
Jianyong Zheng,Xing Lan,Lijuan Huang,Yinjun Zhang,Zhao Wang
D-alanine is widely used in medicine, food, additives, cosmetics, and other consumer items. Esterase derived from Bacillus cereus WZZ001 exhibits high hydrolytic activity and stereoselectivity. In this study, we expressed the esterase gene in Escherichia coli BL21 (DE3). We analyzed the biocatalytic resolution of N-acetyl-DL-alanine methyl ester by immobilized whole E . coli BL21 (DE3) cells, which were prepared through embedding and cross-linking. We analyzed biocatalytic resolution under the optimal conditions of pH of 7.0, temperature of 40°C and substrate concentration of at 700 mM with an enantiomeric excess of 99.99% and e.e. p of 99.50%. The immobilized recombinant B . cereus esterase E . coli BL21 (DE3) cells exhibited excellent reusability and retained 86.04% of their initial activity after 15 cycles of repeated reactions. The immobilized cells are efficient and stable biocatalysts for the preparation of N-acetyl-D-alanine methyl esters.
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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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PLoS One
·
2014
·Vol. 9
·期 4
·e93815
·
IF 3.534
Haishan Qi,Shanshan Li,Sumin Zhao,Di Huang,Menglei Xia,Jianping Wen
To rationally guide the improvement of isobutanol production, metabolic network and metabolic profiling analysis were performed to provide global and profound insights into cell metabolism of isobutanol-producing Bacillus subtilis . The metabolic flux distribution of strains with different isobutanol production capacity (BSUL03, BSUL04 and BSUL05) drops a hint of the importance of NADPH on isobutanol biosynthesis. Therefore, the redox pathways were redesigned in this study. To increase NADPH concentration, glucose-6-phosphate isomerase was inactivated (BSUL06) and glucose-6-phosphate dehydrogenase was overexpressed (BSUL07) successively. As expected, NADPH pool size in BSUL07 was 4.4-fold higher than that in parental strain BSUL05. However, cell growth, isobutanol yield and production were decreased by 46%, 22%, and 80%, respectively. Metabolic profiling analysis suggested that the severely imbalanced redox status might be the primary reason. To solve this problem, gene udhA of Escherichia coli encoding transhydrogenase was further overexpressed (BSUL08), which not only well balanced the cellular ratio of NAD(P)H/NAD(P) + , but also increased NADH and ATP concentration. In addition, a straightforward engineering approach for improving NADPH concentrations was employed in BSUL05 by overexpressing exogenous gene pntAB and obtained BSUL09. The performance for isobutanol production by BSUL09 was poorer than BSUL08 but better than other engineered strains. Furthermore, in fed-batch fermentation the isobutanol production and yield of BSUL08 increased by 11% and 19%, up to the value of 6.12 g/L and 0.37 C-mol isobutanol/C-mol glucose (63% of the theoretical value), respectively, compared with parental strain BSUL05. These results demonstrated that model-driven complemented with metabolic profiling analysis could serve as a useful approach in the strain improvement for higher bio-productivity in further application.
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APPLIED BIOCHEMISTRY AND BIOTECHNOLOGY
·
2014
·Vol. 175
·期 5
·2647-2658
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IF 1.687
He Yu-Cai,Liu Feng,Zhang Dan-Ping,Gao Shan,Li Zhi-Qing,Tao Zhi-Cheng,Ma Cui-Luan
In this study, it was the first report that Bacillus sp. CCZU11-1 was used for the biotransformation of 1,3-propanediol cyclic sulfate (1,3-PDS) and its derivatives. The catalytic performance of Bacillus sp. sulfatase in the biotransformation of 1,3-PDS was significantly improved by biocatalyst permeabilization and immobilization. Using cell permeabilization, the hydrolytic activity of the whole-cell biocatalyst was increased by 3.5-fold after 1.5 h of pretreatment with 10 % ( v / v ) toluene at 30 °C and pH 7.0. Biotransformation of 20 mM 1,3-PDS for 24 h, 1,3-propanediol (1,3-PD) could be obtained in the yield of 97.4 % under the optimized reaction condition. Additionally, the immobilized biocatalysts, permeabilized cells entrapped in calcium alginate, and cross-linked enzyme aggregates were further employed to biotansform 1,3-PDS. Moreover, the total operational time of the immobilized biocatalysts could reach above 240 h with high conversion rate (>90 %).
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APPLIED MICROBIOLOGY AND BIOTECHNOLOGY
·
2013
·Vol. 97
·期 21
·9525-9534
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IF 3.689
Zhang Xiaoyun,Li Baoqing,Wang Ye,Guo Qinggang,Lu Xiuyun,Li Shezeng,Ma Ping
Bacillus atrophaeus CAB-1 displays a high inhibitory activity against various fungal pathogens and suppresses cucumber powdery mildew and tomato gray mold. We extracted and identified lipopeptides and secreted proteins and volatile compounds produced by strain CAB-1 to investigate the mechanisms involved in its biocontrol performance. In vitro assays indicated all three types of products contributed to the antagonistic activity against the fungal pathogen Botrytis cinerea . Each of these components also effectively prevented the occurrence of the cucumber powdery mildew caused by Sphaerotheca fuliginea under greenhouse conditions. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry revealed that the major bioactive lipopeptide was fengycin A (C15–C17). We isolated the crude-secreted proteins of CAB-1 and purified a fraction with antifungal activity. This protein sequence shared a high identity with a putative phage-related pre-neck appendage protein, which has not been reported as an antifungal factor. The volatile compounds produced by CAB-1 were complex, including a range of alcohols, phenols, amines, and alkane amides. O -anisaldehyde represented one of the most abundant volatiles with the highest inhibition on the mycelial growth of B. cinerea . To our knowledge, this is the first report on profiling three types of antifungal substances in Bacilli and demonstrating their contributions to plant disease control.
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危险品化学品经营许可证（带存储）