CHEMOSPHERE
·
2021
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IF 7.086
Xiaoning Li,Hailong Liu,Weiben Yang,Hongjie Sheng,Fang Wang,Jean Damascene Harindintwali,H.M.S.K. Herath,Yinping Zhang
The search for nature-based tools to enhance bioremediation is essential for the sustainable restoration of contaminated ecosystems. Humic acid (HA) is an important component of organic matter in soil and water, but its effect on the microbial degradation of organic pollutants remains unclear. In this study, the biodegradation of pyrene by Mycobacterium sp. NJS-1 with and without HA was investigated. Only around 10.5% of pyrene was biodegraded in the pyrene treatment alone, whereas the addition of HA significantly enhanced biodegradation to the point where over 90% of pyrene was biodegraded. The production of 4,5-dihydropyrene-4,5-diol and phenanthrene-3,4-diol indicated the metabolic pathway via attacking of 4,5-positions of pyrene. Interestingly, 1,2-dimethoxypyrene was detected with the addition of HA, suggesting that HA induced a new ring-opening pathway involving the attack on the 1,2-positions of pyrene. The addition of HA first induced protein self-cleavage behavior with a significant increase in phenylalanine , tyrosine, and tryptophan containing large numbers of COO − groups. Furthermore, it altered the intracellular and extracellular ultrastructure of bacterial cells, promoting their growth in size and number as well as reducing the space between them. Overall, HA increased the ring-opening positions of pyrene and facilitated its interaction with bacterial cells, thus improving its biodegradability . Building upon the findings of this study to further research is conducive to the sustainable solution of environmental pollution .
研究领域:
环境科学
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微生物学
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DOI
PubMed
高影响因子
APPLIED BIOCHEMISTRY AND BIOTECHNOLOGY
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2018
·Vol. 186
·期 2
·496-506
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IF 1.797
Zhou Pei,Fang Ya-kun,Yao Hao-ke,Li Hua,Wang Gang,Liu Yu-peng
In this study, a method for the efficient production of dehydroepiandrosterone (DHEA) from phytosterols in a vegetable oil/aqueous two-phase system by Mycobacterium sp . was developed. After the 3-hydroxyl group of phytosterols was protected, they could be converted into DHEA with high yield and productivity by Mycobacterium sp . NRRL B-3683. In a shake flask biotransformation, 15.05 g l −1 of DHEA and a DHEA yield of 85.39% (mol mol −1 ) were attained after 7 days with an initial substrate concentration of 25 g l −1 . When biotransformation was carried out in a 30-l stirred bioreactor with 25 g l −1 substrate, the DHEA concentration and yield was 16.33 g l −1 and 92.65% (mol mol −1 ) after 7 days, respectively. The results of this study suggest that inexpensive phytosterols could be utilized for the efficient production of DHEA.
研究领域:
微生物学
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生物化学
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制药工程
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PubMed
高影响因子
WORLD JOURNAL OF MICROBIOLOGY & BIOTECHNOLOGY
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2025
·Vol. 41
·期 5
·1-10
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IF 4.2
Bi Yingjing,Han Yun,Bi Yanlan,Zhang Linshang,Sun Shangde
Sterol esters are naturally present in the by-product of edible oil processing, which is generally converted to sterols through saponification. Steroid intermediates play a crucial role in the production of pharmaceuticals, and these intermediates are predominantly synthesized via fermentation of sterol. This research explored the direct conversion of sterol esters into steroid intermediates using Mycobacterium sp. as a fermentation agent. The results demonstrated the successful identification of four steroid intermediates: androstenedione, 1,4-androstadienedione, 22-hydroxy-23,24-bisnorchol-4-ene-3-one, and 22-hydroxy-23,24-bisnorchol-1,4-dien-3-one, their individual intermediate concentrations were as follows: 144.2, 176.2, 30.8, 53.6 mg/L, with a total yield of 404.8 mg/L and a conversion rate of 29.5%. The optimized fermentation conditions included soybean oil at 3%, an initial pH of 7.0, a nitrogen source of 4.5 g/L, and hydroxypropyl-β-cyclodextrin of 15.0 g/L. Proteomic analysis revealed that sterol esters conversion pathway mirrors that of sterol, with an additional hydrolysis process. This work significantly expands our understanding of steroid intermediates production and offers valuable insights for the bioproduction industry. Graphical
研究领域:
生物化学
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制药工程
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微生物学
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DOI
PubMed
高影响因子
Microorganisms
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2025
·Vol. 13
·期 5
·1171
·
IF 4.2
Shuyun Li,Jiazhen Liu,Ping Fang
The development of efficient bioremediation technologies for polycyclic aromatic hydrocarbons contamination is a hot research topic in the environmental field. In this study, we found that theMycobacteriumsp., TJFP1, has the function of degrading low molecular weight PAHs, and further investigated its degradation characteristics using the PAH model compound phenanthrene as a target pollutant. The optimal growth and degradation conditions were determined by single-factor experiments to be 37 °C, pH 9.0, and an initial concentration of 100 mg/L phenanthrene. Under this condition, the degradation efficiency of phenanthrene reached 100% after 106 h of incubation, and the average degradation rate could reach 24.48 mg/L/day. Combined with whole genome sequencing analysis, it was revealed that its genome carries a more complete phenanthrene degradation pathway, including functional gene clusters related to the metabolism of PAHs, such as phd and nid. Meanwhile, intermediates such as phthalic acid were detected; it was determined that TJFP1 metabolizes phenanthrene via the phthalic acid pathway. Simulated contaminated soil experiments were also conducted, and the results showed that the removal rate of phenanthrene from the soil after 20 days of inoculation with the bacterial strain was about 3.7 times higher than that of the control group (natural remediation). At the same time from the soil physical and chemical properties and soil microbial community structure of two levels to explore the changes in different means of remediation, indicating that it can be successfully colonized in the soil, and as a dominant group of bacteria to play the function of remediation, verifying the environmental remediation function of the strains, for the actual inter-soil remediation to provide theoretical evidence. This study provides efficient strain resources for the bioremediation of PAH contamination.
研究领域:
环境科学
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微生物学
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基因组学
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DOI
PubMed
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
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2018
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IF 6.434
Shanshan Sun,Haizhen Wang,Yuanzhi Chen,Jun Lou,Laosheng Wu,Jianming Xu
Mycobacterium sp. WY10 was a highly effective PAHs-degrading bacterium that can degrade phenanthrene (PHE, 100 mg L −1 ) completely within 60 h and 83% of pyrene (PYR, 50 mg L -1 ) in 72 h. In this study, ten and eleven metabolites, respectively, were identified in PHE and PYR degradation cultures, and a detailed PHE and PYR metabolism maps were constructed based on the metabolic results. The strain WY10 degraded PHE and PYR with initial dioxygenation mainly on 3,4- and 4,5-carbon positions, respectively. Thereafter, PYR degradation entered the PHE degradation pathway via the ortho -cleavage. It was observed that the “lower pathway” of PHE and PYR degradations were different. Based on the kinetics of residual metabolites, PHE was degraded in a dominant phthalate pathway and a minor salicylate pathway. However, both phthalate and salicylate pathways played important roles on PYR degradation. The WY10 genome revealed there were fifty-three genes related to PAHs degradations, including a complete gene set for PHE and PYR degradation via the phthalate pathway. The candidate gene/ORF, BOH72_19755, encoding salicylate synthase might contribute in the salicylate pathway.
研究领域:
环境微生物学
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分子生物学
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DOI
PubMed
高影响因子
JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
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2024
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IF 5.7
Qi Han,Youwen Xing,Lulu Yan,Lulu Cao,Zehao Li,Jiandong Jiang,Xihui Xu,Chen Chen
Cyromazine, a triazine insecticide, raises food safety concerns due to residues in vegetables like cowpeas. Microbial metabolism is key for pesticide elimination, but bacteria efficient in cyromazine degradation are limited, with uncharacterized enzymes. This study isolated a highly efficient cyromazine-degrading bacterium, Mycobacterium sp. M15, from a cowpea field. M15 utilized cyromazine as the sole carbon source for its growth and completely degraded 0.5 mM cyromazine within 24 h. The degradation pathway involved hydrolyzing cyromazine to N-cyclopropylammeline and further to N-cyclopropylammelide, with amino groups removed sequentially. The cyclopropylamine group in N-cyclopropionamide continued to hydrolyze to cyanuric acid. A protein, CriA, identified as an aminohydrolase in M15, degraded cyromazine to N-cyclopropylammeline. Using CriA reduced cyromazine residues on cowpea surfaces and completely degraded them in immersion solutions. These findings offer insights into cyromazine’s microbial degradation mechanism and highlight the potential of cyromazine-degrading enzymes in enhancing food safety.
研究领域:
环境科学
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微生物学
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生物技术
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农药化学
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DOI
PubMed
高影响因子
APPLIED MICROBIOLOGY AND BIOTECHNOLOGY
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2023
·Vol. 107
·期 7
·2321-2333
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IF 5
Chi Huibing,Zhu Xiaoyu,Shen Juan,Lu Zhaoxin,Lu Fengxia,Lyu Yunbin,Zhu Ping
Abstract Acrylamide alleviation in food has represented as a critical issue due to its neurotoxic effect on human health. L-Asparaginase (ASNase, EC 3.5.1.1) is considered a potential additive for acrylamide alleviation in food. However, low thermal stability hinders the application of ASNase in thermal food processing. To obtain highly thermal stable ASNase for its industrial application, a consensus-guided approach combined with site-directed saturation mutation (SSM) was firstly reported to engineer the thermostability of Mycobacterium gordonae L-asparaginase (GmASNase). The key residues Gly97, Asn159, and Glu249 were identified for improving thermostability. The combinatorial triple mutant G97T/N159Y/E249Q (TYQ) displayed significantly superior thermostability with half-life values of 61.65 ± 8.69 min at 50 °C and 5.12 ± 1.66 min at 55 °C, whereas the wild-type was completely inactive at these conditions. Moreover, its T m value increased by 8.59 °C from parent wild-type. Interestingly, TYQ still maintained excellent catalytic efficiency and specific activity. Further molecular dynamics and structure analysis revealed that the additional hydrogen bonds, increased hydrophobic interactions, and favorable electrostatic potential were essential for TYQ being in a more rigid state for thermostability enhancement. These results suggested that our strategy was an efficient engineering approach for improving fundamental properties of GmASNase and offering GmASNase as a potential agent for efficient acrylamide mitigation in food industry. Key points
• The thermostability of GmASNase was firstly improved by consensus-guided engineering.
• The half-life and T
m
value of triple mutant TYQ were significantly increased.
• Insight on improved thermostability of TYQ was revealed by MD and structure analysis.
研究领域:
生物化学
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食品科学
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蛋白质工程
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产品关联
DOI
PubMed
高影响因子
Bioresource Technology Reports
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2026
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IF 5
Pengju Li,Yu Liu,Fei Li,Xianliang Yi,Yang Liu,Hao Zhou
Straw is an abundant renewable biomass resource, yet its microbial valorization remains constrained by lignocellulose recalcitrance and the limited characterization of cellulolytic bacteria from coastal and marine environments. Here, we isolated a novel cellulolytic strain, Mycobacterium sp. CBM1, from nearshore sediment in Liaodong Bay (China) using sodium carboxymethyl cellulose (CMC Na) as the sole carbon source. Congo red staining and 16S rRNA sequencing confirmed its cellulolytic phenotype and taxonomic identity. Enzyme assays demonstrated endoglucanase, exoglucanase, and β-glucosidase activities, with optimal production at pH 7, 2% salinity, NH 4 Cl as the nitrogen source, and CMC-Na (300–600 mPa·s) at 0.5 g/L. When cultivated with straw as the sole carbon source (5 g/L), CBM1 converted ∼20% of the substrate within 30 days, accompanied by a decrease in crystallinity index from 46.63% to 37.12%. Whole-genome sequencing revealed a CAZyme repertoire of 230 genes, including 76 glycoside hydrolases, supporting reconstruction of a putative cellulose degradation route. Structural modeling and molecular docking provided supportive hypotheses for substrate recognition by key cellulases. Collectively, these results provide a phenotype-genome-structure basis for developing bacterial candidates for sustainable straw bioconversion.
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DOI
高影响因子
ACS Sustainable Chemistry & Engineering
·
2020
·
IF 7.632
Xia Xiao,Jing-Kai He,Yi-Xin Guan,Shan-Jing Yao
Androst-4-ene-3,17-dione (AD) is an important intermediate of steroid drugs, and the microbial side-chain cleavage of sterols to produce AD by Mycobacterium sp. has attracted much attention. Unfortunately, a low yield of this reaction due to the extremely poor solubility of sterols in aqueous medium is a critical problem. Ionic liquid (IL) as a promising alternative to organic solvents is deemed to increase the solubility of hydrophobic substrates; however, the tolerance of microorganisms to ILs is limited and biocompatible ILs are desperately needed. In this work, cholinium amino acids ([Ch][AA]) ILs were first introduced as cosolvents for the whole-cell bioconversion of phytosterols to produce AD. The physicochemical properties of these novel ILs were investigated on the basis of their structures, and the solubility of phytosterols and AD in [Ch][AA] ILs aqueous solution was determined. The results indicated that moderate cell membrane permeability was obtained by [Ch][AA] ILs, and [Ch][Asp], [Ch][Glu], and [Ch][Gln] showed proper biocompatibility to Mycobacterium sp. MB 3683 cells among 18 kinds of [Ch][AA] ILs. The highest production of AD was achieved in 1% (v/v) [Ch][Asp], which was about twice as high as that in the buffer. Therefore, [Ch][AA] ILs are potential cosolvents in steroid biotransformation to promote medium engineering for a sustainable environment.
研究领域:
生物化学
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环境科学
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微生物学
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DOI
高影响因子
PROCESS BIOCHEMISTRY
·
2026
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IF 4.4
Liyang Xu,Yujia Wang,Feiyu Yan,Wenjing Pan,Yingjia Tong,Jinsong Gong,Xiaomei Zhang,Jinsong Shi,Zhenghong Xu,Hui Li
Mycolicibacterium is a crucial industrial host for steroid biotransformation, yet its genetic engineering has long been limited by inefficient homologous recombination (HR) and strong non-homologous end joining (NHEJ) activity. Here, we established and optimized a suicide plasmid-based genome editing system for Mycobacterium sp. LY-1. The constructed vector p2NILB, combining kanamycin selection with sacB-mediated counter-selection, enabled precise and markerless allelic exchange. Suppression of NHEJ through deletion of ku or ligD , together with optimization of homology arm length, increased gene knockout efficiency to over 70%. This optimized platform was subsequently applied to metabolic engineering of sterol degradation to enhance 9α-hydroxyandrostenedione (9α-OH-AD) biosynthesis. Sequential deletion of five kstD isoenzymes blocked downstream steroid degradation, with kstD1 identified as the major contributor to product loss. Functional analysis revealed KshA2 as the key 9α-hydroxylase, and its overexpression increased the 9α-OH-AD titer to 3.41 g/L. In addition, deletion of the branched-chain acid transporter gene mmpL3 further enhanced 9α-OH-AD production to 4.19 g/L. To overcome substrate utilization limitations under high phytosterol loading conditions, a soybean oil‑Tween 80 solvent system overcame substrate limitation, enabling 15.71 g/L 9α‑OH‑AD from 30 g/L phytosterols. This study provides a robust genome editing framework and an effective strategy for engineering steroid-producing actinobacteria.
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高影响因子
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