SEPARATION AND PURIFICATION TECHNOLOGY
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2020
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IF 5.774
Sagheer A. Onaizi
Emulsification is one of the key mechanisms for the enhancement of crude oil recovery. Although it is desirable to create stable emulsions during the recovery process, the formed emulsions must be easy to break in order to recover the emulsified crude oil before processing. Thus, stable crude oil-in-water (CO/W) nanoemulsions stabilized by rhamnolipid were prepared in this work. The stability of the prepared CO/W nanoemulsions was monitored for at least one month. The prepared CO/W nanoemulsions were very stable with no oil or water separation after 30 days of preparation. Enzymatic demulsification was ineffective in destabilizing CO/W nanoemulsions with less than 10% demulsification even after a month of incubating enzymes in the emulsions. Contrarily, switching the emulsion pH to a lower value using HCl resulted in a complete demulsification within 1 h, irrespective of the bioemulsifier dosage used to stabilize the CO/W nanoemulsion. Surprisingly, switching the emulsion pH to a higher value using NaOH also provided a full destabilization of CO/W nanoemulsions when a lower bioemulsifier dosage was used. However, the efficacy of pH-switching using NaOH decreased with increasing the bioemulsifier dosage. To the best of our knowledge, this is the first study demonstrating the complete breakdown of the CO/W nanoemulsions stabilized by rhamnolipid biosurfactant via pH-swing technique. It is also the first study demonstrating the ineffectiveness of subtilisin A and Alcalase enzymes in breaking the tight CO/W nanoemulsions.
研究领域:
化学工程
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环境科学
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石油工程
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产品关联
DOI
高影响因子
FUEL
·
2023
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IF 7.4
Chen Shi,Xiangrong Liu,Shun-Sheng Zhao,Zaiwen Yang
The biodegradation of Inner Mongolia coal by Pseudomonas japonica ( P. japonica ) was investigated, showing that the biodegradability of P. japonica was related to its secretions: esterase (Es) and rhamnolipid (Rh). Therefore, the efficiencies of coal biodegradation were explored through additions of Es, Rh and the mixture of Es and Rh (Es-Rh) to the biodegradation system, respectively. It was found that the coal biodegradation rate all increased in the presence of Es-Rh, Es or Rh, among which Es-Rh significantly increased the coal biodegradation rate. When the ratio of Es-Rh was 150 mg/mL:1200 mg/mL, the coal biodegradation rate reached a maximum of 65.3% higher than the control group 18.8%, it was because the optical density and esterase activity of P. japonica were the highest, while the electronegativity and adsorption rate of coal samples were the optima. GC–MS of the degradation liquid products showed that the compositions of degradation liquid products in the presence of Es-Rh mainly contained long-chain alkanes, alcohols and ethers, of which the highest content of long-chain alkanes was 81.13%. FTIR analysis confirmed that the C H, C C and -COOR groups in Inner Mongolia coal were degraded in the presence of Es-Rh. XRD analysis demonstrated that the L c and N ave decreased in the presence of Es-Rh, indicating that the crystallization degree of Inner Mongolia coal decreased. This study indicated that the addition of mixture of Es and Rh could significantly promote the degradation of Inner Mongolia coal by P. japonica .
研究领域:
微生物学
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环境科学
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产品关联
DOI
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
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2023
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IF 9.8
Wang Kai Tong,Chaomeng Dai,Jiajun Hu,Jixiang Li,Min-tian Gao,Xueji You,Xin Ru Feng,Zhi Li,Lang Zhou,Yalei Zhang,Xiaoying Lai,Long Kahon,Rongbing Fu
Nanobubbles (NBs), given their unique properties, could theoretically be paired with rhamnolipids (RL) to tackle polycyclic aromatic hydrocarbon contamination in groundwater. This approach may overcome the limitations of traditional surfactants, such as high toxicity and low efficiency. In this study, the remediation efficiency of RL, with or without NBs, was assessed through soil column experiments (soil contaminated with phenanthrene). Through the analysis of the two-site non-equilibrium diffusion model, there was a synergistic effect between NBs and RL. The introduction of NBs led to a reduction of up to 24.3 % in the total removal time of phenanthrene . The direct reason for this was that with NBs, the retardation factor of RL was reduced by 1.9 % to 15.4 %, which accelerated the solute replacement of RL. The reasons for this synergy were multifaceted. Detailed analysis reveals that NBs improve RL's colloidal stability, increase its absolute zeta potential , and reduce its soil adsorption capacity by 13.3 %–19.9 %. Furthermore, NBs and their interaction with RL substantially diminish the surface tension, contact angle, and dynamic viscosity of the leaching solution. These changes in surface thermodynamic and rheological properties significantly enhance the migration efficiency of the eluent. The research outcomes facilitate a thorough comprehension of NBs' attributes and their relevant applications, and propose an eco-friendly method to improve the efficiency of surfactant remediation.
研究领域:
环境科学
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生态学
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产品关联
DOI
PubMed
高影响因子
BIORESOURCE TECHNOLOGY
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2023
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IF 11.4
Jie Zhou,Shixun Liu,Bin Xie,Wenyao Wang,Ning Xu,Anming Xu,Weiliang Dong,Min Jiang
Nitrate plays a crucial role in the high-efficient fermentation production of rhamnolipids (RLs). However, the underlying mechanism remains unclear. Firstly, by knocking out the restriction endonuclease PaeKI and utilizatiing the endogenous CRISPR-Cas-mediated single-plasmid recombineering system, a genome editing system for P. aeruginosa KT1115 has been established. Secondly, an engineered strain KT1115Δ paeKI Δ nirS was obtained with a 87% of reduction in nitric oxide (NO) accumulation and a 93% of reduction in RLs production, revealing the crucial role of NO signaling molecule produced from nitrate metabolism in RLs production. Finally, by combining metabolic engineering of the nitrate metabolism pathway with nitrogen feeding, a new two-stage fermentation process was developed. The fermentation production period was reduced from 168 h to 120 h while achieving a high yield of 0.8 g/g, and the average productivity increased by 55%. In all, this study provides a novel insights in the RLs biosynthesis and fermentation control strategy.
研究领域:
微生物学
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生物技术
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代谢工程
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DOI
PubMed
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2024
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IF 4.9
Mengya Liu,Lulu Lu,Zhiwei Chen,Bin Wang,Yanxiang Li,Qiang Zhang,Usman Farooq,Zhichong Qi
To date, there is still very little knowledge about the combined effects of typical biosurfactants and solution pH values on iron oxide colloid-mediated transport of sulfamerazine (SMZ, a typical sulfonamide antibiotic) in saturated porous media . Herein, the influences of rhamnolipid (a common biosurfactant in the environment) on SMZ mobility in the absence or presence of ferrihydrite (a model iron oxide) colloids in saturated quartz sand were explored. Generally, the rhamnolipid suppressed the transport of SMZ without ferrihydrite colloids owing to the bridging effect of this biosurfactant (i.e., rhamnolipid served as a bridging agent between SMZ and sand). Moreover, ferrihydrite colloids also inhibited SMZ mobility due to the deposition of colloid-associated SMZ. Surprisingly, the presence of rhamnolipid significantly influenced ferrihydrite colloid-mediated transport of SMZ, and this effect was highly dependent on the solution pH. Concretely, rhamnolipid enhanced the inhibitory effects of ferrihydrite colloids on SMZ transport at pH 5.0 because of the increased SMZ retention on the deposited colloids via the bridging effect of biosurfactant. At pH 7.0, the transport-inhibition effects of colloids were weakened by adding rhamnolipid, which was due to the colloid-associated SMZ transport and the promoting electrostatic repulsion between the free SMZ and sand/ the deposited colloids. Surprisingly, ferrihydrite colloids facilitated SMZ transport in the addition of rhamnolipid at pH 9.0. This phenomenon stemmed from the enhanced free SMZ mobility, the colloid-assisted mobility of SMZ, and the competitive deposition between SMZ – species and negatively charged colloids . Moreover, the two-site non-equilibrium model was performed to help interpret the controlling mechanisms for the synergistic effects of rhamnolipid and solution pH on colloid-mediated transport of SMZ. The outcomes of this study offer valuable knowledge about the functions of widespread biosurfactants in the environmental consequences of antibiotics in subsurface systems with iron oxide colloids.
研究领域:
环境科学
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微生物学
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产品关联
DOI
高影响因子
FOOD AND BIOPRODUCTS PROCESSING
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2026
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IF 4.7
Mengqian Zhao,Jian Yin,Zhihong Yang,Xuwei Long
Bacterial resistance poses a growing challenge that requires innovative antibacterial solutions. This study assessed the antibacterial activity of methylamide-modified rhamnolipids (RLs‑MMA). RLs-MMA was first synthesized through amide condensation of methylamine with the carboxyl group of rhamnolipids. The structure of the derivatives was confirmed using FTIR NMR, and LC‑MS analyses. RLs‑MMA were significantly potent against Gram‑positive bacteria. Against Bacillus cereus , the MIC was as low as 16 mg/L. This value represents a 16‑fold improvement on di‑RLs (256 mg/L) and a 4‑fold improvement on mono‑RLs (64 mg/L). The MIC values of RLs‑MMA against Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) were in the range of 64–128 mg/L, significantly lower than values for unmodified RLs (≥256 mg/L). RLs‑MMA alone were ineffective against Gram‑negative bacteria (MIC >512 mg/L). However, combing them with the photosensitizer toluidine blue O (TBO) under red‑light irradiation, the synergy was considerable. Checkerboard assays revealed fractional inhibitory concentration index (FICi) values < 0.375 and < 0.25 for Escherichia coli and Pseudomonas aeruginosa , respectively. According to mechanistic studies, RLs‑MMA permeabilizes bacterial membrane integrity, promotes the uptake of intracellular TBO, and enhances the photodynamic generation of reactive oxygen species (ROS). This combined membrane permeabilization and photodynamic strategy can overcome the outer membrane of Gram‑negative bacteria.
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DOI
高影响因子
Environmental Pollutants and Bioavailability
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2022
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IF 2.828
Bairen Yang,Jiajie Wang,Qingqing Shang,Zhuqiu Sun,Yifan Wu
The effects of rhamnolipid chelating La (III) or Nd (III) on m-dichlorobenzene removal and biofilm growth were investigated. The rhamnolipid chelating La (III) or Nd (III) significantly increased the average m-dichlorobenzene elimination capacity by 24% and 29%, respectively, on day 70–130, and the average wet weights of biomass ranged from 11 kg/m3 to 15 kg/m3 in BTFs on day 100–180 at an inlet load of at 47–98 gm3/h and an EBRT of 60s-90s. Microbial community functional genes about biofilm growth and m-dichlorobenzene removal were also increased. In addition, the rhamnolipid chelating La (III) or Nd (III) can improve the membrane permeability, extracellular polymeric substance (EPS) production, catechol 2,3 dioxygenase (C23O) enzyme, and chlorobenzene dioxygenase activity. These results demonstrate that rhamnolipid chelating La (III) or Nd (III) have the potential to improve the performance of BTFs treating hydrophobic and highly toxic VOCs.
研究领域:
环境科学
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微生物学
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DOI
高影响因子
Environmental Science-Nano
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2026
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IF 5.1
Lixia Li,Tao Jia,Zhichong Qi,Usman Farooq,Yanbin Ma,Fanyan Yang,Minghui Lv,Taotao Lu
Applying biochar as an amendment for the remediation of neonicotinoid pesticide-contaminated soils is a promising way to reduce the environmental risks posed by these pollutants. Rhamnolipid, a widespread glycolipid biosurfactant in soils, may regulate the transport of biochar colloids and/or pesticides in soil–water environments. Currently, critical knowledge gaps remain regarding how biosurfactant/biochar affects neonicotinoid pesticide mobility. Herein, rhamnolipid was employed to explore its influences on neonicotinoid pesticide (acetamiprid or nitenpyram) mobility and biochar colloid-affected mobility of pesticides at variable solution pH levels (5.0–9.0). In the binary system, rhamnolipid restrained pesticide transport owing to the biosurfactants' bridging effects, forming soil–biosurfactant–pesticide ternary complexes; similarly, biochar colloids also inhibited pesticide mobility because of colloid–pesticide complex deposited on soil surfaces. Notably, the degree of the inhibiting impacts of biochar/biosurfactant varied with pesticide types (acetamiprid > nitenpyram), which was attributed to differences in the chemical features of pesticides (e.g., hydrophobicity). Interestingly, the pH-dependent inhibition effects followed the order pH 5.0 > pH 7.0 > pH 9.0, which were ascribed to the different deposition amounts of biosurfactant molecules or biochar colloids. Surprisingly, in the ternary system, adding biosurfactant weakened the repressive influences of biochar colloids on pesticide migration over a broad pH range of 5.0 to 9.0 because of the reduced retention of colloid-associated pesticides and the great mobility of free neonicotinoid pesticides. Additionally, the degree of rhamnolipid's suppressive effects declined as the pH value increased. These findings provide critical insights into the environmental behaviors and fate of neonicotinoid pesticides influenced by ubiquitous biosurfactants in biochar-amended soils.
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产品关联
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2025
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IF 5.4
Caiping Hu,Usman Farooq,Baoshuai Li,Dalu Yu,Bo Zhou,Jinxiao Wang,Weifeng Chen,Zhichong Qi
As an effective soil amendment, biochar can reduce the adverse effects and environmental impacts of neonicotinoid pesticides. Rhamnolipid, an active and common biosurfactant in soil systems, may alter the co-transport behaviors of biochar colloids and pesticides. Nevertheless, biosurfactant-mediated changes in pesticide mobility in soils affected by biochar colloids are currently lacking. Herein, the single or combined effects of biochar colloids and rhamnolipid on the transport properties of dinotefuran (DTF, a typical neonicotinoid pesticide) in soil matrix were investigated. When the influents contained biochar colloids, the DTF transport was reduced, primarily via colloid-associated DTF deposition and pesticide bound to the deposited colloids on porous media surfaces. Meanwhile, rhamnolipid also restrained DTF mobility because of its bridging effect (i.e., this biosurfactant mediated DTF-soil binding through molecular bridging). However, rhamnolipid notably diminished the suppressed influences of biochar colloids on DTF transport because of the decrease of colloid-associated DTF retention and the high mobility of free DTF. Moreover, the degree of rhamnolipid's weakened effects was related to the solution pH values (i.e., the influences declined as the pH values increased). Because rhamnolipid exhibited greater inhibition effects on the binding abilities of colloids to pesticide molecules under lower pH conditions (pH 5.0), leading to more free DTF mobility. The results underscore the critical roles of ubiquitous biosurfactants in the fate and risks of pesticides when biochar is used as an amendment for contaminated soil.
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产品关联
DOI
高影响因子
COLLOIDS AND SURFACES B-BIOINTERFACES
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2026
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IF 5.9
Nan Wang,Shiyu Ma,Fangyu Jiao,Zhe Yu,Fengshu Fei,Jianting Huang,Chuanlong Guo
RL/BAI nanomicelles (~100 nm) enhance baicalein biocompatibility. • RL/BAI triggers mitochondrial dysfunction and mtDNA release in TNBC cells. • RL/BAI activates cGAS-STING pathway to suppress tumor growth and metastasis. Triple-negative breast cancer (TNBC) remains an intractable malignancy due to the lack of specific therapeutic targets and high metastatic potential. Herein, we fabricated rhamnolipid (RL)-encapsulated baicalein (BAI) nanomicelles (RL/BAI) via a thin-film hydration method. Molecular dynamics (MD) simulations revealed that RL and BAI spontaneously assembled into stable nanomicelles (~100 nm) driven by van der Waals and hydrophobic interactions, achieving high encapsulation efficiency (~85 %) and excellent biocompatibility. In 4T1 cells, RL/BAI nanomicelles enhanced cellular uptake and achieved efficient mitochondrial colocalization, triggering mitochondrial membrane potential (MMP) collapse, excessive mitochondrial reactive oxygen species (mtROS) generation, and mitochondrial DNA (mtDNA) release. These events activated the cGAS-STING pathway, as evidenced by increased phosphorylation of STING, TBK1, and IRF-3, together with upregulation of IFN-γ and NF-κB, ultimately promoting immunogenic cell death. In 4T1 xenograft models, RL/BAI significantly inhibited primary tumor growth and lung metastasis, remodeled the pro-inflammatory tumor microenvironment by upregulating pro-inflammatory cytokines and promoting dendritic cell maturation, with no obvious systemic toxicity. Collectively, RL/BAI nanomicelles exert anti-TNBC effects through mitochondrial damage and cGAS-STING pathway activation, providing a novel natural biosurfactant-based nanomedicine strategy for TNBC treatment.
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DOI
高影响因子
MICROBIAL PATHOGENESIS
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2019
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IF 2.581
Xiaonan Chen,Pengyu Li,Yuanna Shen,Yiqing Zou,Gang Yuan,Haiyan Hu
Antibiotics resistance of H. pylori has been increasing constantly accompanied with decreasing clearance rate clinically, which is demonstrated to be closely related to biofilms with higher resistance than planktonic bacteria for the dense extracellular polymeric substances . Rhamnolipid (RHL) is proved to not only damage the structure of biofilm, but also potentially inhibit bacterial adhesion . To investigate if RHL could promote eradicating rate of the conventional triple therapy to H. pylori biofilm and hence attenuate the resistance and relapse of H. pylori , first-line antibiotics clarithromycin (CLR), amoxicillin (AMX) or/and proton pump inhibitor (PPI) involved single, dual or triple therapies were compared with RHL-containing drug combinations on eradicating H. pylori biofilm. The residual biofilm biomass, the survival of bacteria inside the remaining biofilm and the planktonic bacteria dispersed from the biofilm after treatment were tested. Combination with RHL significantly improved the ability of antibiotics to eradicate H. pylori biofilm, especially RHL combined with AMX and PPI could eradicate more than 95% of biofilm showing much more effective ability than the conventional triple therapy CLR + AMX + PPI. Additionally, the combination of RHL and antibiotics could effectively inhibit the biofilm formation at lower concentration. Thus, RHL might be used as a potential antibiotic adjuvant on anti- H. pylori therapy to enhance eradicating ability of antibiotics to biofilms.
研究领域:
微生物学
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药理学
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传染病学
✓ 已验证
DOI
PubMed
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2023
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IF 5.2
Mengya Liu,Lulu Lu,Qiang Zhang,Usman Farooq,Taotao Lu,Yanxiang Li,Deliang Li,Zhichong Qi
The mobility and deposition of sulfonamide antibiotics (SAs) in soil porous media may be impacted by the presence of rhamnolipid (a typical biosurfactant), which is ubiquitous in the natural environment. Herein, the transport characteristics of various SAs, such as sulfamerazine (SMZ), sulfamethazine (SMT), and sulfanilamide (SNM) in soil columns with rhamnolipid, were explored. The mobility of SAs in the soil columns was in the sequence of SNM > SMT > SMZ. The observation was mainly due to the differences in the hydrophobic properties of various antibiotics. Interestingly, rhamnolipid inhibited the mobility of the three SAs over a broad solution pH range (5.0–9.0) primarily because of the interactions between the hydrophobic groups of the deposited rhamnolipid on the soil surfaces and parts of SAs molecules (i.e., rhamnolipid acted as a bridging agent between soil and antibiotic). Furthermore, at a given rhamnolipid concentration, the inhibitory effect of rhamnolipid on SMZ transport was the greatest among the three antibiotics due to SMZ’s greatest hydrophobicity . Additionally, the transport-inhibition influence of rhamnolipid declined as the solution pH values rose. This phenomenon was attributed to the decline of the bridge effects induced by the decreased adsorbed rhamnolipid on soil surfaces. Innovative findings from this study provide helpful information regarding the contribution of biosurfactants on the environmental behaviors of these ubiquitous antibiotic contaminants in soil-water systems.
研究领域:
环境科学
·
微生物学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）