JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
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2022
·
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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Journal of Cleaner Production
·
2022
·
IF 11.072
Yuan Chen,Yuancai Chen,Boxi Wang,Chenchen Mao,Chao Liu,Rongrong Liu,Bing Yan
Microbial reduction is a sustainable approach for both environmental remediation and recycling of precious metals from waste. Bacteria-mediated reduction of palladium ions (Pd 2+ ) in wastewater under mild conditions is such a strategy. However, external electron donors are usually required for palladium bioreduction. Herein, a novel gram-positive bacterium, Bacillus thuringiensis Y9 ( B. thuringiensis Y9), was found to reduce Pd 2+ to palladium nanoparticles (Pd-NPs) with endogenous electron donors. Transcriptomic analyses revealed 443 and 439 differentially expressed genes response to palladium treatment under anaerobic and aerobic conditions , respectively. It was found the genes encoding NADH-quinone oxidoreductase, dehydrogenases , cytochrome c reductase, cytochrome c oxidase , quinone cycle and ribE in B. thuringiensis Y9 have strong positive relationship to palladium reduction. The removal efficiencies of palladium by B. thuringiensis Y9 are as high as 93 mg g −1 under anaerobic conditions and 60 mg g −1 under aerobic conditions. Hydrogenase also plays vital role in the bioreduction process. The maximum Pd removal ratio of 99.18% was obtained with the primary influencing factors using response surface methodology (RSM). Our study provides a novel and sustainable strategy for Pd recovery from wastewater. The transcriptome data are valuable for understanding the global bioreduction mechanism of the microbial conversion of palladium.
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SCIENCE OF THE TOTAL ENVIRONMENT
·
2022
·
IF 10.753
Limei Cai,Xiaoming Liu,Zhiqiang Tian,J.P. Michaud,Zhongjian Shen,Zhen Li,Songdou Zhang,Xiaoxia Liu
The widespread adoption of Bt crops expressing insecticidal proteins derived from Bacillus thuringiensis has created a need to assess the potential effects of these toxins on non-target organisms, especially species such as Arma custos , a generalist predator that provides important biological control services in many field crops in Asia. Direct dietary exposure of A. custos to Cry1Ah and Vip3Aa proteins produced no adverse effects on life history traits, despite continuous exposure throughout development and early adult life to concentrations significantly higher than the Bt protein concentration likely encountered by A.custos in the field, even when feeding directly on Bt plants. Enzyme-linked immunosorbent assay confirmed the presence of Bt proteins in A. custos midguts, but quantitative real-time PCR analysis of 12 genes associated with detoxification, antioxidative responses, immune responses, and metabolism revealed no significant changes in expression in adult bugs. Indirect exposure to these toxins via consumption of intoxicated prey, larvae of Helicoverpa armigera (Hübner), likewise produced no negative impacts on survival, development, adult weight, or female fecundity in either the F0 (exposed) or F1 (unexposed) generation, but female fresh weight was reduced in the F0 generation by the Cry1Ah (50 μg/g) treatment. Finally, a competitive binding assay with labelled protein and a ligand blotting assay both demonstrated that the Cry1Ah protein could not bind to receptors on the midgut brush border membrane vesicles (BBMVs) of A. custos adults. Therefore, we conclude that Cry1Ah and Vip3Aa proteins are unlikely to have significant negative effects on A. custos populations if employed as plant-incorporated protectants in field crops.
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PLANT DISEASE
·
2022
·Vol. 106
·期 9
·
IF 4.614
Chunwei Wang,Tiankun Duan,Luxin Shi,Xiqian Zhang,Weixin Fan,Meiqin Wang,Jianming Wang,Lu Ren,Xiaojun Zhao,Yan Wang
To develop an effective and environmentally safe strategy to control postharvest gray mold caused by Botrytis cinerea , Bacillus siamensis strain YJ15 isolated from blueberry was used to test the biocontrol potential. It is interesting to find that the volatile organic compounds (VOCs) emitted from strain YJ15 exhibited significant antifungal activity against Botrytis cinerea as well as 11 other plant-pathogenic fungi, with a percentage of mycelial growth inhibition from 74.96 to 92.81%. Additionally, VOCs from strain YJ15 could reduce significantly the disease incidence and lesion diameter with the increasing of fermentation time, indicating great biocontrol potential for controlling blueberry postharvest gray mold. Furthermore, the VOCs were collected by using headspace solid-phase microextraction fiber, and the composition of VOCs was further revealed by using gas chromatography coupled with quadruple mass spectrometry. In total, 24 kinds of VOCs, including 5 alkanes, 2 aldehydes, 3 ketones, 5 alcohols, 1 alkene, 5 acids and esters, 2 aromatic compounds, and 1 sulfur compound, were emitted at 1, 3, 5, and 7 days after inoculation. Among these VOCs, eight antifungal VOCs could inhibit mycelial growth of B. cinerea . It is important to highlight that, although 1-butanol and 3-methyl-1-butanol were the most abundant compounds, 2-ethylhexanol, 1-heptanol, and 1,3-xylene have proved to be more toxic to B. cinerea than 3-methyl-1-butanol, propanethioic acid, 2,2-dimethyl-, ethyl 2-methylbutyrate, 2-heptanone, and 1-butanol, which provide new, promising biofumigants for the control of postharvest gray mold caused by B. cinerea .
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APPLIED AND ENVIRONMENTAL MICROBIOLOGY
·
2022
·Vol. 88
·期 19
·
IF 5.005
Shuai Liu,Yuwei Gao,Lin Quan,Mei Yang,Yong-Zhong Wang,Changjun Hou
An increase in exoenzyme production can be enhanced by environmental stresses such as graphene oxide (GO) stress, but the link between the two events is still unclear. In this work, the effect of GO as an environmental stress factor on exoenzyme (lignocellulolytic enzyme, amylase, peptidase, and protease) biosynthesis was investigated in Bacillus subtilis Z2, and a plausible mechanism by which cytosolic Ca2+ regulates lignocellulolytic enzyme production in B. subtilis Z2 subjected to GO stress was proposed. The filter paper-hydrolyzing (FPase [representing total cellulase]), carboxymethylcellulase (CMCase [representing endoglucanase]), and β-glucosidase activities and extracellular protein concentration of the wild-type strain under 10 μg/mL GO stress were 1.37-, 1.64-, 1.24-, and 1.16-fold those of the control (without GO stress), respectively. Correspondingly, the transcription levels of lignocellulolytic enzyme genes, cytosolic Ca2+ level, and biomass concentration of B. subtilis were all increased. With lignocellulolytic enzyme from B. subtilis used to hydrolyze alkali-pretreated rice straw, the released reducing sugar concentration reached 265.53 mg/g, and the removal rates of cellulose, hemicellulose, and lignin were 52.4%, 30.1%, and 7.5%, respectively. Furthermore, transcriptome data revealed that intracellular Ca2+ homeostasis played a key role in regulating the levels of gene transcription related to the synthesis of lignocellulolytic enzymes and exoenzymes. Finally, the use of Ca2+ inhibitors (LaCl3 and EDTA) and deletion of spcF (a calmodulin-like protein gene) further demonstrated that the overexpression of those genes was regulated via calcium signaling in B. subtilis subjected to GO stress.IMPORTANCE To effectively convert lignocellulose into fermentable sugars, high lignocellulolytic enzyme loading is needed. Graphene oxide (GO) has been shown to promote exoenzyme (lignocellulolytic enzyme, amylase, peptidase, and protease) production in some microorganisms; however, the regulatory mechanism of the biosynthesis of lignocellulolytic enzymes under GO stress remains unclear. In this work, the lignocellulolytic enzyme production of B. subtilis under GO stress was investigated, and the potential mechanism by which B. subtilis enhanced lignocellulolytic enzyme production through the calcium signaling pathway under GO stress was proposed. This work revealed the role of calcium signaling in the production of enzymes under external environmental stress and provided a direction to facilitate lignocellulolytic enzyme production by B. subtilis.
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JOURNAL OF HAZARDOUS MATERIALS
·
2020
·
IF 9.038
Ning Hou,Qiaoruo Wang,Yang Sun,Xianyue Li,Qiuying Song,Xinxin Jiang,Baoxin Li,Xinyue Zhao,Hailian Zang,Dapeng Li,Chunyan Li
In recent years, special attention has been devoted to biodemulsifiers as a new type of environment-friendly demulsifiers. A novel biodemulsifying oxalate decarboxylase (OxdC) secreted by Bacillus mojavensis XH1 is reported in the present study. A genome-wide comparison showed that strains with high demulsification efficiencies all possess alkane degradation genes. An analysis of the differentially expressed genes and proteins induced by different substrates showed that OxdC secreted by XH1 was an effective demulsifier. Moreover, the demulsification ability was verified by prokaryotic gene expression, knockout and complementation analyses. OxdC from XH1 exhibited a strong demulsification capacity and significantly outperformed the model protein Bacillus subtilis 168 OxdC (Yvrk), which shared a high amino acid similarity but showed limited demulsification ability. Based on a comparison of the structural characteristics, the hydrophobic amino acids on the surface of OxdC were identified as a key factor driving the favorable demulsification activity of XH1. The metabolic pathways of XH1 used liquid paraffin and glucose as substrates, illustrating that hydrocarbons are necessary for biodemulsifier secretion. The present study provides new insight into the application of OxdC as an additional genetic resource in biodemulsification.
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JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
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2020
·
IF 4.192
Lei Wang,Yongmei Xia,Lingqia Su,Jing Wu
γ-Cyclodextrin (γ-CD), a cyclic oligosaccharide containing eight glucose units linked by α-1,4-glycosidic bonds, can be produced from starch using cyclodextrin glycosyltransferase (CGTase). Unfortunately, this enzymatic process produces mixtures of α-, β-, and γ-CD. In this study, amino acid residues in the subsite −3 (T47 and F91) and the central subsite (Y186) of Bacillus clarkii γ-CGTase were modified to improve the γ-CD production. The cyclization activities and product specificities of mutants T47H and F91W were similar to those of the wild-type. The cyclization activities of mutants F91N and F91L were significantly greater than those of the wild-type but their γ-CD product specificities were lower. Finally, the central subsite mutant Y186W displayed a γ-CD specificity (94.6%) significantly greater than that of the wild-type (77.1%). To maximize the γ-CD yield, the effects of added complexing agents were investigated. Among the cyclic complexing agents tested, low-boiling cyclododecanone was the smallest that precipitated with γ-CD. When cyclododecanone was used with Y186W, the total CD yield reached 72.6%, and 96.6% of the product was γ-CD. These results, which represent the highest γ-CD yield ever reported, may provide a way to improve large-scale γ-CD preparation and expand the uses of γ-CD in the future.
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BIOPROCESS AND BIOSYSTEMS ENGINEERING
·
2020
·Vol. 44
·期 4
·727-735
·
IF 2.419
Wang Hongrao,Han Shuran,Wang Jiayi,Yu Shuyu,Li Xiaoyan,Lu Lei
Laccases are versatile oxidases that are capable of decolorizing various synthetic dyes. Recombinant Bacillus amyloliquefaciens laccase was immobilized as magnetic cross-linked enzyme aggregates (M-CLEAs) for application in dye decolorization. Several parameters influencing the activity recovery were evaluated during the synthesis of M-CLEAs. With ammonium sulfate as precipitant, maximum activity was recovered by cross-linking with 0.16% glutaraldehyde for 1 h. The prepared M-CLEAs exhibited improved activity under alkaline conditions. It remained 74% activity after incubation at 60 °C for 5 h. Enhanced tolerance towards NaCl was also observed for the M-CLEAs, with 68% activity remaining in the presence of 1 M NaCl. The immobilized laccase could rapidly decolorize more than 93% of reactive black 5 and indigo carmine in 1 h, while its catalytic efficiency towards reactive blue 19 was relatively low. After four cycles of consecutive reuse, the M-CLEAs could decolorize 92% of indigo carmine. The easy recovery and reusability of M-CLEAs facilitate the potential application of bacterial laccase in dye decolorization.
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BIOCHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 3.978
Yaru Zhang,Jing Ren,Quan Wang,Shuxiang Wang,Shuna Li,Hongya Li
In the current work, studies were conducted for understanding oxidation characteristics and biodegradation potential of a dye-decolorizing peroxidases from Bacillus amyloliquefaciens (BaDyP) for triphenylmethane dye crystal violet (CV). Recombinant BaDyP from Bacillus amyloliquefaciens MN-13 exhibits a broad substrates profile. It can oxidize ABTS, veratryl alcohol, Mn 2+ , azo dye reactive black 5, anthraquinone dye reactive blue 19, but cannot oxidize guaiacol. The maximum BaDyP activity against ABTS was obtained at 30 ℃ and pH 4.0. When CV was treated by BaDyP for 72 h, the degradation percentage of 63.0 % was observed. UV–vis spectra and HPLC/MS analysis indicated that CV degradation occurred via N -demethylation and cleavage of conjugated chromophore structure. The identified degradation products included stepwise N -demethylated intermediates during the N -demethylation of CV and, 4-( N -methylamino)-4′-( N ’-methylamino) benzophenone and 4-( N -methylamino)-4′-amino benzophenone after cleavage of conjugated chromophore structure. Based on these data, a hypothetic mechanism of CV degradation mediated by BaDyP was proposed in this study. Finally, it is worth to be noted that BaDyP possessed high decolorization efficiency (72.3 % removal ADMI) for actual dye effluent. These results demonstrated that BaDyP might be used as an efficient biocatalyst for the enzymatic pretreatment of dyes in wastewater.
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ANTONIE VAN LEEUWENHOEK INTERNATIONAL JOURNAL OF GENERAL AND MOLECULAR MICROBIOLOGY
·
2020
·Vol. 113
·期 10
·1467-1477
·
IF 2.674
Yin Yi-Rui,Sang Peng,Yang Feng-Li,Li Tao,Yang Run-Feng,Liu Hong-Yan,Luo Zong-Long,Li Wen-Jun,Yang Li-Quan
A β-glucosidase gene ( bsbgl1a ) from Bacillus sp. CGMCC 1.16541 was expressed in Escherichia coli BL21 and subsequently characterized. The amino acid sequence shared 83.64% identity with β-glucosidase (WP_066390903.1) from Fictibacillus phosphorivorans . The recombinant β-glucosidase (BsBgl1A) had a molecular weight of 52.2 kDa and could hydrolyze cellobiose, cellotriose, cellotetrose, p-nitrophenyl-β- d -glucopyranoside ( p NPG), and p-nitrophenyl-β- d -xylopyranoside ( p NPX). Optimal activity for BsBgl1A was recorded at 45 °C with a pH between 5.6 and 7.6, and 100% of its activity was maintained after a 24 h incubation between pH 4 and 9. Kinetic characterization revealed an enzymatic turnover (Kcat) of 616 ± 2 s −1 (with cellobiose) and 3.5 ± 0.1 s −1 (with p-nitrophenyl-β- d -glucopyranoside). Interestingly, the recombinant enzyme showed cupric ion (Cu 2+ ), sodium dodecyl sulfate (SDS) and alcohol tolerance at 10 mM for Cu 2+ and 10% for both SDS and alcohol. Additionally, BsBgl1A had high tolerance for glucose (Ki = 2095 mM), which is an extremely desirable feature for industrial applications. Following the addition of BsBgl1A (0.05 mg/ml) to a commercial cellulase reaction system, glucose yields from sugarcane bagasse increased 100% after 1 day at 45 °C. This work identifies a Cu 2+ , SDS, alcohol, and glucose tolerant GH1 β-glucosidase with potential applications in the hydrolysis of cellulose for the bioenergy industry.
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FOOD CONTROL
·
2023
·
IF 6
Suping Li,Jingyu Hu,Shiqi Ning,Wei Li,Ru Jiang,Jianguo Huang,Yong Li
Citrus fruit post-harvest decay has caused economic loss for fruit-dependent industries worldwide in recent decades. However, bio-preservatives offer a promising and sustainable solution. In this study, culture experiments were carried out to assess the ability of Bacillus velezensis HY19, which we previously identified, to inhibit common pathogenic fungi in postharvest citrus fruit. HY19 was capable of producing extracellular siderophores and hydrolases (protease, phosphatase, and cellulase). The cells and metabolites (fermentation broth and volatiles) of the bacterium exhibited strong suppression against Penicillium italicum , P. digitatum , and Colletotrichum gloeosporioides . LC-MS analysis of B. velezensis HY19 fermentation broth (BFB) revealed 13 antimicrobial substances (simvastatin, cinnamic acid, cyclopentanone, etc.), 3 antifungal pesticide intermediates (M-cresol, 4-hydroxybenzaldehyde, and L-menthyl acetoacetate), and P-salicylic acid. GC-MS detected 18 antimicrobial substances (2-nonanol, 2-nonanone, benzoic acid, etc.) in HY19's volatile organic compounds (VOCs). Transcriptome analysis of P. digitatum exposed to BFB stress revealed that numerous genes involved in diverse biological processes, such as DNA replication and cell wall biosynthesis, were differentially expressed. Moreover, BFB inhibited the expression of multiple genes responsible for the biosynthesis of N-glycan and proteins in P. digitatum . BFB enhanced antioxidant enzyme activities in citrus peels, reduced electrolyte leakage and reactive oxygen species (ROS) accumulation, and induced the disease resistance in citrus fruit, leading to the decrease in the infection of pathogenic fungi on citrus fruit. During storage at low-temperature (4–8 °C), BFB inhibited the disease incidence in citrus fruit for up to 90 days and achieved over 60% control efficacy. Additionally, BFB had no impact on fruit quality, making it a lower risk option. Considering the benefits of sustainability and environmentally friendly options, it could be concluded that BFB was an effective alternative for controlling citrus diseases and had the potential to be used as a fruit preservative.
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ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2023
·Vol. 30
·期 31
·76867-76880
·
IF 5.8
Huang Jiaqing,Liu Cenwei,Price Gordon W.,Wang Yixiang
Bacillus cellulasensis Zn-B isolated from vegetable soil was highly adaptable to Zinc (Zn) and Cadmium (Cd). Cd, but not Zn, adversely affected the total protein spectrum and functional groups of Bacillus cellulasensis Zn-B. Up to 31 metabolic pathways and 216 metabolites of Bacillus cellulasensis Zn-B were significantly changed by Zn and Cd (Zn&Cd). Some metabolic pathways and metabolites related to functional groups of sulfhydryl (-SH) and amine (-NH-) metabolism were enhanced by Zn&Cd addition. The cellulase activity of Bacillus cellulasensis Zn-B was up to 8.58 U mL −1 , increased to 10.77 U mL −1 in Bacillus cellulasensis Zn-B + 300 mg L −1 Zn, and maintained at 6.13 U mL −1 in Bacillus cellulasensis Zn-B + 50 mg L −1 Cd. The vegetables’ cellulose content was decreased by 25.05–52.37% and 40.28–70.70% under the action of Bacillus cellulasensis Zn-B and Bacillus cellulasensis Zn-B + 300 mg L −1 Zn. Those results demonstrated that Zn could significantly enhance cellulase activity and biodegradability of Bacillus cellulasensis Zn-B to vegetable cellulose. Bacillus cellulasensis Zn-B can survive in vegetable soil accumulated with Zn&Cd. The tolerance concentration and adsorption capacity of Bacillus cellulasensis Zn-B to Zn were up to 300 mg L −1 and 56.85%, indicating that Bacillus cellulasensis Zn-B acting as a thermostability biological agent had an essential advantage in accelerating the degradation of discarded vegetables by Zn and were beneficial to maintain organic matter content of vegetable soil. Graphical Abstract
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危险品化学品经营许可证（带存储）