PROCESS BIOCHEMISTRY
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2022
·
IF 4.885
Chengchen Cai,Ming Zhang,Haiming Chen,Wenxue Chen,Weijun Chen,Qiuping Zhong
Mango juice (MJ) has high nutritional value and decent flavor. However, its aroma could be easily changed by heat treatment during processing, which affects its acceptability and quality. In this study, Bacillus subtilis -HNU-B3 that could transfer carotenoid, was obtained from orchard soil to improve the aroma of fermented mango juice (FMJ). Compared with MJ, the organic acid content of FMJ by B. subtilis -HNU-B3 was significantly changed, and the contents of succinic acid and malic acid were increased to 3.68 mg/mL and 2.04 mg/mL, respectively. Moreover, volatile compounds identified by headspace solid-phase micro-extraction gas-phase mass spectrometry in FMJ were norisoprenoid and acetoin, accounting for 51.52 % of the total volatile substances. In addition, B. subtilis -HNU-B3 fermentation significantly increased the antioxidant capacity and total phenol contents of MJ, and the activity of carotenoid cleavage dioxygenase was 188 U/L. In conclusion, the aroma of FMJ could be improved by B. subtilis -HNU-B3 through increasing the content of norisoprenoid and acetoin. Our results provide theatrical support for Bacillus subtilis to improve the aroma quality of FMJ.
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APPLIED BIOCHEMISTRY AND BIOTECHNOLOGY
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2023
·
IF 3
Ma Lingling,Wang Ying,Wang Xin,Lü Xin
The process of tobacco aging plays a significant role in enhancing the smoking experience by improving the flavor and quality of tobacco leaves. During natural aging, the metabolic activity of the microbes on the surface of tobacco leaves will be greatly changed. Besides, starch and protein are two of the main macromolecular compounds causing the poor smoking quality of tobacco leaves which to be degraded for better tobacco quality. In this study, a bacterium with the simultaneously degrading ability of starch (degradation rate of 33.87%) and protein (degradation rate of 20%) has been screened out from high-class tobacco leaf and then inoculated into low-class tobacco leaf by solid-state fermentation for quality improvement. The changes in components related to carbon and nitrogen showed that the strain had an obvious effect on the quality improvement of tobacco leaves. After that, GC-MS analyses displayed the volatile flavor compounds which become rich and the flavor has been improved. It has been proved that inoculation solid-state fermentation by dominant strain could improve tobacco quality, as well as instead of the traditional natural aging process which greatly shortens the aging process. The work also offers a helpful strategy for solid-state products for deep fermentation.
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BIOCATALYSIS AND BIOTRANSFORMATION
·
2023
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IF 1.8
Zhi Chen,Zhaohe Dong,Xin Ju,Lishi Yan,Liangzhi Li,Donzhi Wei
6-Hydroxynicotinic acid emerged as a pivotal intermediate for fine chemicals. The current study aims to screen novel nicotinate dehydrogenase-producing strains. Based on the high-throughput UV coloration method, a novel nicotinate dehydrogenase-producing strain named Bacillus paramycoides was first and successfully screened from soil and gram staining as 16S rRNA gene sequencing was conducted to further confirm its accuracy. The fermentation medium formula is determined as seignette salt (5 g/L), tryptone (10 g/L), K2HPO4 (2 g/L), and nicotinic acid (4 g/L) after a single factor and orthogonal test. The activity of nicotinate dehydrogenase produced by B. paramycoides after optimization reached 1.23 U/mL, which was the highest ever reported. In addition, the enzyme characterization results revealed that the optimum reaction temperature and pH were 40 °C and 7.0, respectively. Furthermore, B. paramycoides nicotinate dehydrogenase exhibited good thermostability with more than 50% of the highest enzyme activity retained at 50 °C after 8 h incubation, which was better than ever reported. The pH stability results suggested that nicotinate dehydrogenase possessed a narrow pH ranging from 6.0 to 8.0. In addition, shaker speed demonstrated a positive relation with enzyme activity since shaker speed could affect mass transfer and dissolved oxygen concentration. Finally, it could completely transform nicotinic acid to 6-HNA within 3 h when the substrate loading is 15 g/L. In conclusion, these results indicated that B. paramycoides nicotinate dehydrogenase could serve as a potential candidate for bioproduction of 6-HNA.
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Microorganisms
·
2023
·Vol. 11
·期 10
·2397
·
IF 4.5
Wensheng Shen,Xiangrong Liu,Chen Shi,Jie Yang,Shunsheng Zhao,Zaiwen Yang,Dan Wang
The biodegradation of tar-rich coal in the Ordos Basin was carried out byBacillus licheniformis(B. licheniformis) under actions of four kinds of surfactants, namely, a biological surfactant (Rh), a nonionic surfactant (Triton X-100), an anionic surfactant (LAS), and a cationic surfactant (DTAB). The biodegradation rates under the actions of Triton X-100, LAS, Rh, DTAB, and the control group (without surfactant) were 59.8%, 54.3%, 51.6%, 17.3%, and 43.5%, respectively. The biodegradation mechanism was studied by examining the influences of surfactants on coal samples, bacteria, and degradation products in the degradation process. The results demonstrated that Rh, Triton X-100, and LAS could promote bacterial growth, while DTAB had the opposite effect. Four surfactants all increased the cell surface hydrophobicity (CSH) ofB. licheniformis, and Triton X-100 demonstrated the most significant promotion of CSH. The order of improvement in microbial cell permeability by surfactants was DTAB > TritonX-100 > LAS > Rh > control group. In the presence of four surfactants, Triton X-100 exhibited the best hydrophilicity improvement for oxidized coal. Overall, among the four surfactants, Triton X-100 ranked first in enhancing the CSH of bacteria and the hydrophilicity of oxidized coal and second in improving microbial cell permeability; thus, Triton X-100 was the most suitable surfactant for promotingB. licheniformis’s biodegradation of tar-rich coal. The GC-MS showed that, after the action of Triton X-100, the amount of the identified degradation compounds in the toluene extract of the liquid product decreased by 16 compared to the control group, the amount of dichloromethane extract decreased by 6, and the amount of ethyl acetate extract increased by 6. Simultaneously, the contents of alkanes in the extracts of toluene and dichloromethane decreased, lipids increased, and ethyl acetate extract exhibited little change. The FTIR analysis of the coal sample suggested that, under the action of Triton X-100, compared to oxidized coal, theHar/HandA(CH2)/A(CH3) of the remaining coal decreased by 0.07 and 1.38, respectively, indicating that Triton X-100 enhanced the degradation of aromatic and aliphatic structures of oxidized coal. Therefore, adding a suitable surfactant can promote the biodegradation of tar-rich coal and enrich its degradation product.Keywords:tar-rich coal;Bacillus licheniformis;biodegradation;surfactant;enrichment
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NUCLEIC ACIDS RESEARCH
·
2023
·Vol. 51
·期 21
·11952-11966
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IF 14.9
He Hehe,Li Youran,Ma Xufan,Xu Sha,Zhang Liang,Ding Zhongyang,Shi Guiyang
Synthetic regulation of metabolic fluxes has emerged as a common strategy to improve the performance of microbial cell factories. The present regulatory toolboxes predominantly rely on the control and manipulation of carbon pathways. Nitrogen is an essential nutrient that plays a vital role in growth and metabolism. However, the availability of broadly applicable tools based on nitrogen pathways for metabolic regulation remains limited. In this work, we present a novel regulatory system that harnesses signals associated with nitrogen metabolism to redirect excess carbon flux in Bacillus licheniformis. By engineering the native transcription factor GlnR and incorporating a sorbitol-responsive element, we achieved a remarkable 99% inhibition of the expression of the green fluorescent protein reporter gene. Leveraging this system, we identified the optimal redirection point for the overflow carbon flux, resulting in a substantial 79.5% reduction in acetoin accumulation and a 2.6-fold increase in acetate production. This work highlight the significance of nitrogen metabolism in synthetic biology and its valuable contribution to metabolic engineering. Furthermore, our work paves the way for multidimensional metabolic regulation in future synthetic biology endeavors.
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APPLIED BIOCHEMISTRY AND BIOTECHNOLOGY
·
2020
·Vol. 192
·期 3
·935-951
·
IF 2.277
Guo Zongren,Long Liangkun,Ding Shaojun
L-Ribulose and L-ribose are two high-value unnatural sugars that can be biosynthesized by sugar isomerases. In this paper, an L-arabinose isomerase (BvAI) from Bacillus velezensis CICC 24777 was cloned and overexpressed in Escherichia coli BL21 (DE3) strain. The maximum activity of recombinant BvAI was observed at 45 °C and pH 8.0, in the presence of 1.0 mM Mn 2+ . Approximately 207.2 g/L L-ribulose was obtained from 300 g/L L-arabinose in 1.5 h by E. coli harboring BvAI. In addition, approximately 74.25 g/L L-ribose was produced from 300 g/L L-arabinose in 7 h by E. coli co-expressing BvAI and L-RI from Actinotalea fermentans ATCC 43279 (AfRI). This study provides a feasible approach for producing L-ribose from L-arabinose using a co-expression system harboring L-Al and L-RI.
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Microbial Cell Factories
·
2019
·Vol. 18
·期 1
·1-10
·
IF 4.402
Tao Weiyi,Lin Junzhang,Wang Weidong,Huang He,Li Shuang
Background Bioemulsifiers are surface-active compounds, which exhibit advantages including low toxicity, higher biodegradability and biocompatibility over synthetic chemical surfactants. Despite their potential benefits, some obstacles impede the practical applications of bioemulsifiers, including low yields and high purification costs. Here, we aimed to exploit a novel protein bioemulsifier with efficient emulsifying activity and low-production cost, as well as proposed a design-bioemulsifier system that meets different requirements of industrial emulsification in the most economical way. Results The esterase AXE was first reported for its efficient emulsifying activity and had been studied for possible application as a protein bioemulsifier. AXE showed an excellent emulsification effect with different hydrophobic substrates, especially short-chain aliphatic and benzene derivatives, as well as excellent stability under extreme conditions such as high temperature (85 °C) and acidic conditions. AXE also exhibited good stability over a range of NaCl, MgSO 4 , and CaCl 2 concentrations from 0 to 1000 mM, and the emulsifying activity even showed a slight increase at salt concentrations over 500 mM. A design-bioemulsifier system was proposed that uses AXE in combination with a variety of polysaccharides to form efficient bioemulsifier, which enhanced the emulsifying activity and further lowered the concentration of AXE needed in the complex. Conclusions AXE showed a great application potential as a novel bioemulsifier with excellent emulsifying ability. The AXE-based-designer bioemulsifier could be obtained in the most economical way and open broad new fields for low-cost, environmentally friendly bioemulsifiers.
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JOURNAL OF DAIRY SCIENCE
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2019
·
IF 3.082
Kejin Zhuang,Hongfu Li,Ziwei Zhang,Shuang Wu,Yashuo Zhang,Edward M. Fox,Chaoxin Man,Yujun Jiang
ABSTRACT Bacillus cereus sensu lato is one of the most harmful bacterial groups affecting the quality and safety of powdered infant formula (PIF). In this study, samples were collected from the raw materials and processing environments of PIF. A total of 84 isolates were identified as Bacillus cereus sensu stricto ( B. cereus s. s. ) by 16S rRNA analysis, molecular typing technology, and physiological and biochemical tests. The 84 B. cereus s. s. strains were assigned to panC group II, group III, and group IV. Then, the 7 housekeeping genes glpF , gmk , ilvD , pta , pur , pycA , and tpi were selected for multilocus sequence typing. Results showed that the 84 isolates were clustered into 24 sequence types (ST), and 14 novel ST were detected. Among the 24 ST, ST999 (19/84, 22.62%) and ST1343 (13/84, 15.48%) predominated. The correlation between processing areas and ST showed that the processing environments of the production and packing areas were the most susceptible to contamination by B. cereus s. s . Spores of these ST showed different heat resistance phenotypes evaluated by the analysis of D T (time in minutes of spore decimal reduction at each temperature) and Z values (temperature increase required to reduce the D T value to one-tenth of the original). Spores from group III according to panC gene analysis were the most heat resistant. These findings will help us to better understand B. cereus s. s. contamination and control in PIF processing environments.
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CHEMICAL RESEARCH IN CHINESE UNIVERSITIES
·
2019
·Vol. 35
·期 5
·792-798
·
IF 1.071
Dong Lu,Xu Yongkai,Zhang Yun,Sun Aijun,Hu Yunfeng
Bacillus sp. DL-2 was isolated from the deep sea of the Western Pacific and further utilized as novel biocatalysts to efficiently asymmetrically hydrolyze (±)-1-phenylethyl acetate. After the optimization of hydrolytic reactions, chiral chemicals ( R )-1-phenylethanol and ( S )-1-phenylethyl acetate were obtained with high optical purities (96% and 99.8%, respectively). Our research is about the asymmeric hydrolysis of (±)-1-phenylethyl acetate using whole-cell biocatalysts. In addition, the optical purity of ( S )-1-phenylethyl acetate generated through the kinetic resolution of (±)-1-phenylethyl acetate using the whole-cells of Bacillus sp. DL-2 was the highest report so far. Using the whole cells of deep sea bacterium Bacillus sp. DL-2 as the biocatalysts is an environmentally friendly method and will play critical roles in industrial asymmetric synthesis.
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FOOD AND CHEMICAL TOXICOLOGY
·
2024
·
IF 3.9
Junxia Liu,Peng Li,Xiao Li,Yanli Xie,Fred Mwabulili,Shumin Sun,Yuhui Yang,Weibin Ma,Qian Li,Hang Jia
Deoxynivalenol (DON) contamination in cereals and their products poses a potential threat to animal and human health, however, physical and chemical detoxification methods deplete nutrients and cannot specifically remove DON. This study aims to identify novel and efficient DON-degrading enzymes, providing practical support for their application in biodegradation. A novel DON-degrading aldo-keto reductase named AKR11A2 was identified from Bacillus velezensis Vel-HNGD-F2 through BlastP comparison. AKR11A2, an enzyme with a molecular mass of 34.8 kDa encoded by a 933 bp gene, exhibited optimal activity at pH 9 and 40°C, while demonstrating remarkable thermal and alkaline stability by retaining over 90% of its activity. UPLC-MS/MS analysis revealed that the m/z of the DON degradation product was 295.1, identified as 3- epi -DON, formed through the direct isomerization of DON. Notably, zebrafish experiments demonstrated that the liver toxicity of the degradation product was significantly lower than that of DON. AKR11A2 effectively degraded 50.69% of the DON in contaminated corn, highlighting its practical application in food safety. These findings indicate that the study achieved the biodegradation of DON and provide a promising theoretical and technological support for the application of DON detoxifying enzymes in food and feed products.
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Nanomaterials
·
2024
·Vol. 14
·期 4
·340
·
IF 4.4
Xiaozhou Li,Jie Chen,Bin Wu,Zhen Gao,Bingfang He
Exploring an appropriate immobilization approach to enhance catalytic activity and reusability of cellulase is of great importance to reduce the price of enzymes and promote the industrialization of cellulose-derived biochemicals. In this study, Fe3O4magnetic nanoparticles (MNPs) were functionalized with meso-2,3-dimercaptosuccinic acid to introduce carboxyl groups on the surface (DMNPs). Then, melamine–glutaraldehyde dendrimer-like polymers were grafted on DMNPs to increase protein binding sites for the immobilization of processive endoglucanase EG5C-1. Moreover, this dendrimer-like structure was beneficial to protect the conformation of EG5C-1 and facilitate the interaction between substrate and active center. The loading capacity of the functionalized copolymers (MG-DMNPs) for EG5C-1 was about 195 mg/g, where more than 90% of the activity was recovered. Immobilized EG5C-1 exhibited improved thermal stability and increased tolerability over a broad pH range compared with the free one. Additionally, MG-DMNP/EG5C-1 biocomposite maintained approximately 80% of its initial hydrolysis productivity after five cycles of usage using filter paper as the substrate. Our results provided a promising approach for the functionalization of MNPs, enabling the immobilization of cellulases with a high loading capacity and excellent activity recovery.
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Journal of Environmental Sciences
·
2025
·
IF 6.3
Wei Zhang,Xu Zeng,Jiayi Dong,Yibin Su,Erik Jeppesen,Liqing Wang,Sicheng Yin
Microorganism-based biocontrol strategies for harmful cyanobacterial blooms have gained increasing attention due to their ecological compatibility and species-specific targeting. Despite this, research on algicidal bacteria effectiveness against the invasive cyanobacterium Raphidiopsis raciborskii remains limited. Research has been conducted on the Bacillus subtilis strain CH21, which was isolated from Chaohu Lake in China. exhibiting potent indirect anticyanobacterial activity against R. raciborskii . Within 48 h of exposure, the cell-free filtrate of strain CH21 achieved 96.2 % removal efficiency of R. raciborskii cells. Physiological and morphological analyses revealed severe disruption of the photosynthetic apparatus (Fv/Fm and Yield values reduced to zero within 16 h), oxidative stress (elevation in malondialdehyde content and reactive oxygen species, reduction in superoxide dismutase and catalase activity), and cellular damage, including pseudovacuole collapse, the degradation of polyphosphate granules and cytoplasmic leakage. Metabolomic profiling identified surfactin-class lipopeptides as putative bioactive agents, which demonstrated exceptional stability across a wide thermal (25–121 °C) and pH (3–13) range. These findings highlight B. subtilis CH21 as a promising candidate for targeted biocontrol of R. raciborskii blooms, supporting the development of environmentally mitigation technologies to be used in cases where it is difficult to control R. raciborskii by external nutrient loading reduction or if the response to such loading reductions are slow.
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危险品化学品经营许可证（带存储）