Crude petroleum pollution causes some serious ecological disasters in the ocean.Marine sediment microbial fuel cells(MSMFCs)have been utilized as a novel method for in-situ degradation and a long-term power source.Her...Crude petroleum pollution causes some serious ecological disasters in the ocean.Marine sediment microbial fuel cells(MSMFCs)have been utilized as a novel method for in-situ degradation and a long-term power source.Herein,the effect of different concentrations of rhamnolipids biosurfactant on the electrochemical performance of MSMFCs anode and the higher efficiency of oil degradation are creatively investigated.The results indicate that the anode in sediment containing rhamnolipids effectively enriches the indigenous electrogenic Pseudophaeobacter and Pseudomonas,which significantly enhances the electrochemical performance of the MSMFCs.Under rhamnolipids at the concentration of 200 mg kg^(-1)in sediment,the anode specific capacitance(401.45 Fm^(-2)),exchange current density(4.87×10^(-2)mAm^(-2)),and cell maximum power density(140.24 mWm^(-2))increase by 2.50,38.65,and 2.11 times,respectively,in comparison with its natural sediment.And the oil degradation rate(40.06%)was higher than the blank(17.55%).It demonstrates that the synergistic effect between electrochemical catalytic degradation and emulsifying solubilization of rhamnolipids surfactant directly accelerates the degradation of petroleum in marine sediment,which will provide a novel method and theoretical guidance for in-situ degradation and efficient removal of crude petroleum on ocean floor.展开更多
Biochar (BC) and rhamnolipid (RL) is used in bioremediation of petroleum hydrocarbons,however,the combined effect of BC and RL in phytoremediation has not been studied until now.In this paper,the phytoremediation of p...Biochar (BC) and rhamnolipid (RL) is used in bioremediation of petroleum hydrocarbons,however,the combined effect of BC and RL in phytoremediation has not been studied until now.In this paper,the phytoremediation of petroleum hydrocarbon-contaminated soil using novel plant Spartina anglica was enhanced by the combination of biochar (BC) and rhamnolipid (RL).Samples of petroleum-contaminated soil (10,30 and 50 g/kg) were amended by BC,BC+ RL and rhamnolipid modified biochar (RMB),respectively.After 60 day's cultivation,the removal rate of total petroleum hydrocarbons (TPHs) for unplanted soil (UP),planted soil (P),planted soil with BC addition (P-BC),planted soil with BC and RL addition (P-BC + RL) and planted soil with addition ofRMB (P-RMB) were 8.6%,19.1%,27.7%,32.4% and 35.1% in soil with TPHs concentration of 30 g/kg,respectively.Compared with UP,the plantation of Spartina anglica significantly decreased the concentration of C8-14 and tricyclic PAHs.Furthermore,the application of BC and RMB alleviated the toxicity of petroleum hydrocarbons to Spartina anglica via improving plant growth with increasing plant height,root vitality and total chlorophyll content.High-throughput sequencing result indicated that rhizosphere microbial community of Spartina anglica was regulated by the application of BC and RMB,with increase of bacteria and plant mycorrhizal symbiotic fungus in biochar and RMB amended soil.展开更多
In this work,rhamnolipid production was investigated using waste frying oil as the sole carbon source. By culture in shaking flasks,a naturally isolated strain synthesized rhamnolipid at concentration of 12.47 g/L and...In this work,rhamnolipid production was investigated using waste frying oil as the sole carbon source. By culture in shaking flasks,a naturally isolated strain synthesized rhamnolipid at concentration of 12.47 g/L and its mutant after treatment by UV light increased this productivity to 24.61 g/L. Fermentation was also conducted in a 50 L bioreactor and the productivity reached over 20 g/L. Hence,with a stable and high productive mutant strain,it could be feasible to reuse waste frying oil for rhamnolipid production on industrial scale.展开更多
The potential biodegradation of crude oil was assessed based on the development of a fermentative process with a strain of Pseudomonas aeruginosa which produced 15.4 g/L rhamnolipids when cultured in a basal mineral m...The potential biodegradation of crude oil was assessed based on the development of a fermentative process with a strain of Pseudomonas aeruginosa which produced 15.4 g/L rhamnolipids when cultured in a basal mineral medium using glycerol as a sole carbon source. However, neither cell growth nor rhamnolipid production was observed in the comparative culture system using crude oil as the sole carbon source instead. As rhamnolipid, an effective biosurfactant, has been reported to stimulate the biodegradation of hydrocarbons, 1 g/L glycerol or 0.22 g/L rhamnolipid was initially added into the medium to facilitate the biodegradation of crude oil. In both situations, more than 58% of crude oil was degraded and further converted into accumulated cell biomass and rhamnolipids. These results suggest that Pseudomonas aeruginosa could degrade most of crude oil with direct or indirect addition of rhamnolipid. And this conclusion was further supported by another adsorption experiment, where the ad-sorption capacity of crude oil by killed cell biomass was negligible in comparison with the biologic activities of live cell biomass.展开更多
Biotrickling filters(BTFs) for hydrophobic chlorobenzene(CB) purification are limited by mass transfer and biodegradation. The CB mass transfer rate could be improved by 150 mg/L rhamnolipids. This study evaluated the...Biotrickling filters(BTFs) for hydrophobic chlorobenzene(CB) purification are limited by mass transfer and biodegradation. The CB mass transfer rate could be improved by 150 mg/L rhamnolipids. This study evaluated the combined use of Fe^(3+) and Zn^(2+) to enhance biodegradation in a BTF over 35 day. The effects of these trace elements were analysed under different inlet concentrations(250, 600, 900, and 1200 mg/L) and empty bed residence times(EBRTs;60, 45, and 32 sec). Batch experiments showed that the promoting effects of Fe^(3+)/Zn^(2+) on microbial growth and metabolism were highest for 3 mg/L Fe^(3+) and 2 mg/L Zn^(2+), followed by 2 mg/L Zn^(2+), and lowest at 3 mg/L Fe^(3+). Compared to BTF in the absence of Fe^(3+) and Zn^(2+), the average CB elimination capacity and removal efficiency in the presence of Fe^(3+) and Zn^(2+) increased from 61.54 to 65.79 g/(m 3 hr) and from 80.93% to 89.37%, respectively, at an EBRT of 60 sec. The average removal efficiency at EBRTs of 60, 45, and 32 sec increased by 2.89%, 5.63%, and 11.61%, respectively. The chemical composition(proteins(PN), polysaccharides(PS)) and functional groups of the biofilm were analysed at 60, 81, and 95 day. Fe^(3+) and Zn^(2+) significantly enhanced PN and PS secretion, which may have promoted CB adsorption and biodegradation. High-throughput sequencing revealed the promoting effect of Fe^(3+) and Zn^(2+) on bacterial populations. The combination of Fe^(3+) and Zn^(2+) with rhamnolipids was an efficient method for improving CB biodegradation in BTFs.展开更多
Oily wastewater generated by various industries creates a major ecological problem throughout the world. The tra- ditional methods for the oily wastewater treatment are inefficient and costly. Surfactants can promote ...Oily wastewater generated by various industries creates a major ecological problem throughout the world. The tra- ditional methods for the oily wastewater treatment are inefficient and costly. Surfactants can promote the biodegradation of pe- troleum hydrocarbons by dispersing oil into aqueous environment. In the present study, we applied rhamnolipid-containing cell-free culture broth to enhance the biodegradation of crude oil and lubricating oil in a conventional aerobically-activated sludge system. At 20 ℃, rhamnolipids （11.2 mg/L） increased the removal efficiency of crude oil from 17.7% （in the absence of rham- nolipids） to 63%. At 25 ~C, the removal efficiency of crude oil was over 80% with the presence of rhamnolipids compared with 22.3% in the absence of rhamnolipids. Similarly, rhamnolipid treatment （22.5 mg/L） for 24 h at 20℃ significantly increased the removal rate of lubricating oil to 92% compared with 24% in the absence of rhamnolipids. The enhanced removal of hydrocarbons was mainly attributed to the improved solubility and the reduced interfacial tension by rhamnolipids. We conclude that a direct application of the crude rhamnolipid solution from cell culture is effective and economic in removing oily contaminants from wastewater.展开更多
The effective leaching of rare earth elements（La, Ce, Y and Eu） from simulated contaminated soil using bio-surfactant was investigated in a lab-scale column leaching experiment, where anionic biosurfactant rhamnolip...The effective leaching of rare earth elements（La, Ce, Y and Eu） from simulated contaminated soil using bio-surfactant was investigated in a lab-scale column leaching experiment, where anionic biosurfactant rhamnolipid and non-ionic biosurfactant saponin were used as washing solutions. Soil properties and the rare earth element fractions were analysed to define the effect of leaching on soil and elemental speciation. Column leaching results showed that saponin solution was more effective than rhamnolipid in the removal of the four rare earth elements tested, with the accumulative removal efficiency of La, Ce, Y and Eu following flushing with 400 mL of 25 g/L saponin, reaching 35.258%, 26.072%, 31.476% and 30.849%, respectively. The change in REE speciation showed that REE removed from soils were mainly derived from the acid-soluble and residual fractions released when rhamnolipid solution was used as a leaching agent. However, for saponin leaching, removed REE amounts were derived from acid-soluble and reducible fractions. Complexation interactions were identified between saponin and REEs, according to infrared spectroscopy and ion exchange data, with saponin complexing with La, Ce, Y, and Eu at a complex ratio of 1：1.展开更多
Interfacial properties rhamnolipids from an extract produced by a strain of Pseudomonas aeruginosa were analyzed in this study. The extract of rhamnolipid was characterized by surface tension in different conditions;i...Interfacial properties rhamnolipids from an extract produced by a strain of Pseudomonas aeruginosa were analyzed in this study. The extract of rhamnolipid was characterized by surface tension in different conditions;interfacial tension with different hydrocarbons;critical micelle concentration under different pH and temperatures;particle size and emulsification capacity using laser light profiling. It was observed that the rhamnolipids extract are sensitive to variations in pH, thermostable and function as good emulsificant for emulsification of methyl methacrylate. The emulsion stability order in function of the oil phase was methyl methacrylate > emulsions of castor oil > emulsion n-heptane > emulsion toluene > emulsion hexadecane > octane emulsion. The data presented show that rhamnolipid extracts may be used to formulate stable emulsions of methyl methacrylate. This process can be used to do nano/microsphere of polymethyl methacrylate.展开更多
In highly urbanized areas,pollution from anthropogenic activities has compromised the integrity of the land,decreasing soil availability for agricultural practices.Dibenzothiophene(DBT)is a heterocyclic aromatic hydro...In highly urbanized areas,pollution from anthropogenic activities has compromised the integrity of the land,decreasing soil availability for agricultural practices.Dibenzothiophene(DBT)is a heterocyclic aromatic hydrocarbon frequently found in urbanized areas,and is often used as a model chemical to study the microbial transformation of pollutants.The potential for human exposure and its health risk makes DBT a chemical of concern;thus,it needs to be environmentally managed.We utilized glycerol to stimulate Burkholderia sp.C3 in order to degrade DBT in respect to①DBT biodegradation kinetics,②bacterial growth,③rhamnolipid(RL)biosynthesis,and④RL secretion.Under an optimum glycerol-to-DBT molar ratio,the DBT biodegradation rate constants increased up to 18-fold and enhanced DBT biodegradation by 25%–30%at day 1 relative to cultivation with DBT alone.This enhancement was correlated with an increase in bacterial growth and RL biosynthesis.Proteomics studies revealed the enzymes involved in the upper and main steps of RL biosynthesis.The RL congeners Rha-C10-C10,Rha-Rha-C10-C10,Rha-Rha-C10-C12,and Rha-Rha-C12-C12 were identified in the medium supplemented with glycerol and DBT,whereas only Rha-C12-C12 was identified in cultures without glycerol or with RL inhibitors.The studies indicated that glycerol enhances DBT biodegradation via increased RL synthesis and bacterial growth.The results warrant further studies of environmental biostimulation with glycerol to advance bioremediation technologies and increase soil availability for agricultural purposes.展开更多
Rhamnolipid production by Pseudomonas aeruginosa ATCC 9027 with waste frying oil as sole carbon source was studied using response surface method. Cultures were incubated in shaking flask with temperature, NO3- and Mg2...Rhamnolipid production by Pseudomonas aeruginosa ATCC 9027 with waste frying oil as sole carbon source was studied using response surface method. Cultures were incubated in shaking flask with temperature, NO3- and Mg2+ concentrations as the variables. Meanwhile, fed-batch fermentation experiments were conducted. The results show that the three variables are closely related to rhamnolipid production. The optimal cultivation conditions are of 6.4 g/L NaNO3 , 3.1 g/L MgSO4 at 32 ℃, with the maximum rhamnolipid production of 6.6 g/L. The results of fed-batch fermentation experiments show that feeding the oil in two batches can enhance rhamnolipid production. The best time interval is 72 h with the maximum rhamnolipid production of 8.5 g/L. The data are potentially useful for mass production of rhamnolipid on oil waste with this bacterium.展开更多
An environment friendly bio-surfactant of rhamnolipid(RL) was used as a solvent. The enzymatic reaction of oleic acid catalyzed by lipase and lignin peroxidase(lip) was evaluated. The optimum conditions of enzymatic r...An environment friendly bio-surfactant of rhamnolipid(RL) was used as a solvent. The enzymatic reaction of oleic acid catalyzed by lipase and lignin peroxidase(lip) was evaluated. The optimum conditions of enzymatic reaction catalyzed by lipase(lip) were water to amphiphile molar ratio of 30(20), RL of 60(60) critical micelle concentration(CMC), pH of 7.0(3.0) and temperature of 40(30) °C, respectively. The change of enzyme conformation indicates that, for catalytic of lipase, water content is the most important factor of the enzymatic reaction of oleic acid, and p H for lip. With individual optimum conditions, the enzymatic efficiency of oleic acid catalyzed by lipase is higher than that by lip. In the presence of ethanol, the enzymatic reaction of oleic acid catalyzed by lipase suits Ping-Pong Bi-Bi mechanism. As an alternative to chemical reversed micelles, the RL reversed micelles are promising methods to enzymatic reaction of oleic acid.展开更多
Hydrophobic organic compounds(HOCs)and heavy metals(HMs)are toxins that usually coexist in natural environments.Due to the differences in their properties,it remains challenging to simultaneously remove HMs and HOCs.I...Hydrophobic organic compounds(HOCs)and heavy metals(HMs)are toxins that usually coexist in natural environments.Due to the differences in their properties,it remains challenging to simultaneously remove HMs and HOCs.In this study,the removal of phenanthrene(Phe)and lead(Pb)from co-contaminated soils by single rhamnolipid(RL)and mixed RL-sophorolipid(SL)biosurfactants were evaluated via soil column experiments.Biosurfactant micelle sizes were determined by dynamic light scattering,and the mechanisms of micelle solubilization were studied.The effects of biosurfactant concentrations,pH,washing agent salinity and the ageing time of polluted soils on Phe and Pb desorption efficiencies were also assessed.The substantial removal of Phe and Pb using mixed RL-SL systems,when molar fractions of RLs were 0.7,was attributed to large mixed micelle formation and lower sorption losses of these systems.The optimal pH value was 6.0,while Phe desorption was favoured at high RLs and low ionic strengths.However,the RLs concentration and ionic strength had no obvious influence on Pb removal.In addition,both Phe and Pb desorption decreased with increased ageing of the polluted soils.Combined RL-SL biosurfactants can be effective for simultaneously removing HOCs and HMs from polluted soils.展开更多
Biosurfactants were synthesized by Pseudomonas aeruginosa （P.A.）, using sugar cane molasses as carbon source. Assays were conducted in a shaker with agitation speed of 200 rpm, temperature of 38 ℃ and aeration rat...Biosurfactants were synthesized by Pseudomonas aeruginosa （P.A.）, using sugar cane molasses as carbon source. Assays were conducted in a shaker with agitation speed of 200 rpm, temperature of 38 ℃ and aeration ratio （Vm/Vf） of 0.4 and 0.6. A concentration of 3.0% was used for the carbon and energy source （molasses） and of 0.3% for the nitrogen source （NaNO3）. Samples were removed at regular times until 96 hours of cultivation. The reduction in surface tension was measured using the ring method; cell concentration was obtained by the dry mass and substrate consumption by the DNS method. The metabolite produced was extracted and quantified by the thioglycolic method. The results showed a maximum surface tension reduction of 46.57% after 60 h, 3.63 g/L of biomass after 8 h （μXmax =0.15 h^-1）, 79.60% of substrate consumption （μs= 0.67 h-1） and 4.47 g/L of rhamnolipid （μp=0.029 h^-1）.展开更多
Forecasting the properties of nanoemulsions without engaging in expensive and time-consuming experimental research can yield significant benefits across multiple applications.This study examines the capability of mach...Forecasting the properties of nanoemulsions without engaging in expensive and time-consuming experimental research can yield significant benefits across multiple applications.This study examines the capability of machine learning to precisely forecast the interfacial tension and viscosity of crude oilwater nanoemulsions stabilized by rhamnolipid biosurfactant.Four artificial neural network models were created and assessed for nanoemulsions composed of different concentrations of crude oil and biosurfactants.The performance evaluation of the artificial neural network models demonstrated mean squared error values below 2.26E-03 and coefficients of determination greater than 0.999,signifying exceptional predictive accuracy.The mean overall deviation for all models was determined to be around 0.004%,indicating a negligible divergence from experimental results.The findings indicate that the developed artificial neural network models can accurately and reliably predict interfacial tension and viscosity values,providing an efficient alternative to experimental methods,with potential applications in optimizing nanoemulsion formulations for industrial purposes.展开更多
Rhamnolipids are one of the most effective biosurfactants that are of great interest in industrial applications such as enhancing oil recovery, health care, cosmetics, pharmaceutical processes, food processing, deterg...Rhamnolipids are one of the most effective biosurfactants that are of great interest in industrial applications such as enhancing oil recovery, health care, cosmetics, pharmaceutical processes, food processing, detergents for protein folding, and bioremediation due to their unique characteristics such as low toxicity, surface active property to reduce surface/interfacial tensions, and excellent biodegradability. The genes and metabolic path- ways for rhamnolipid synthesis have been well elucidated, but its cost-effective production is still challenging. Pseudomonas aeruginosa, the most powerful rhamnolipid producer, is an opportunistic pathogen, which limits its large scale production and applications. Rhamnolipid production using engineered strains other than Pseudomo- nas aeruginosa such as E. coli and Pseudomonas putida has received much attention. The highest yield of rhamnolipids is achieved when oil-type carbon sources are used, but using cheaper and renewable carbon sources such as lignocellulose would be an attractive strategy to reduce the production cost of rhamnolipids for various industrial applications.展开更多
Milk fat globule membrane (MFGM) phospholipids-based nanostructures were developed and their functionalization with rhamnolipids (RLs) was carried out to enhance the preservation of cheese against resistant foodborne ...Milk fat globule membrane (MFGM) phospholipids-based nanostructures were developed and their functionalization with rhamnolipids (RLs) was carried out to enhance the preservation of cheese against resistant foodborne pathogens i.e.,Listeria monocytogenes and Escherichia coli .Void (without nisin) and nisin-loaded RLs functionalized MFGM nanostructures (RLs-MFGM-NS) were fabricated by ultrasonication-assisted self-assembly method.Cubic morphology of void and loaded RLs-MFGM-NS and pristine MFGM nanostructures (MFGM-NS) was observed under scanning electron microscopy (SEM),which indicated uniform size ranging from 43 nm (void RLs-MFGM-NS) to 194 nm (loaded RLs-MFGM-NS).FTIR analyses confirmed the electrostatic interaction,predominantly H-bonding and linkage of carboxyl ester group of MFGM with C–H group in RLs after functionalization of NS.Furthermore,quantitative antimicrobial assay on cheese slices confirmed the broad-spectrum potential of intrinsically active nanostructures (due to RLs) having synergistic activity with nisin against L.monocytogenes and E.coli .Hence,nisin-loaded RLs-MFGM-NS can be applied as promising bioactive additives for sustained preservation of cheese.展开更多
Rhamnolipids are a class ofbiosurfactants that have a great potential to be used in industries. Five proteins/enzymes, namely RhlA, RhlB, RhlC, RhlG and RhlI, are critical for the production of rhamnolipids in Pseudom...Rhamnolipids are a class ofbiosurfactants that have a great potential to be used in industries. Five proteins/enzymes, namely RhlA, RhlB, RhlC, RhlG and RhlI, are critical for the production of rhamnolipids in Pseudomonas aeruginosa. Four of the 5 proteins except RhlC were successfully over-expressed in E. coli and three of them （RhlA, RhlB and RhlI） were purified and obtained in milligram quantities. The purified proteins were shown to be folded in solution. Homology models were built for RhlA, RhlB and RhlI. These results lay a basis for further structural and functional characterization of these proteins in vitro to favor the construction of super strains for rhamnolipids production.展开更多
Background:Traditional synthetic surfactants used in shampoos,such as sodium lauryl sulfate(SLS),raise significant environmental and dermatological concerns due to their poor biodegradability,high irritation potential...Background:Traditional synthetic surfactants used in shampoos,such as sodium lauryl sulfate(SLS),raise significant environmental and dermatological concerns due to their poor biodegradability,high irritation potential,and petrochemical origin.In contrast,biosurfactants offer eco-friendly,skin-compatible alternatives that align with green chemistry principles and support sustainable personal care.Objective:This review aims to critically evaluate the functional,environmental,and dermatological performance of microbial biosurfactants,particularly rhamnolipids and sophorolipids,as sustainable alternatives to synthetic surfactants in shampoo formulations.Methods:A comprehensive analysis of published research was conducted to assess biosurfactant properties,production methods,comparative cleansing and foaming efficacy,biodegradability,skin compatibility,and formulation challenges.The review includes physicochemical data,in vitro and in vivo performance metrics,and case examples from commercial products.Results:Rhamnolipids and sophorolipids demonstrated sebum removal efficiencies of 85–95%,foam volume retention above 75%,and biodegradability rates of 60–95%within 7–14 days.They exhibited lower irritation indices(<1.0)and caused≤10%protein loss in skin models,in contrast to SLS,which caused up to 40%protein denaturation.However,biosurfactant integration is challenged by higher costs($20–40/kg),pH sensitivity,and limited consumer familiarity.Formulation strategies such as hybrid surfactant systems,pH buffering,and synergistic blends were reviewed to overcome these barriers.Conclusion:Biosurfactants offer a promising path toward microbiome-friendly,sustainable shampoos without compromising cleansing or sensory performance.To enable broader adoption,efforts must focus on improving fermentation efficiency,optimizing formulation stability,and educating consumers.Strategic positioning of biosurfactants based on their unique functional profiles can help meet evolving demands for eco-conscious and dermatologically gentle hair care.展开更多
基金financially supported by the National Natural Science Foundation of China(No.22075262)。
文摘Crude petroleum pollution causes some serious ecological disasters in the ocean.Marine sediment microbial fuel cells(MSMFCs)have been utilized as a novel method for in-situ degradation and a long-term power source.Herein,the effect of different concentrations of rhamnolipids biosurfactant on the electrochemical performance of MSMFCs anode and the higher efficiency of oil degradation are creatively investigated.The results indicate that the anode in sediment containing rhamnolipids effectively enriches the indigenous electrogenic Pseudophaeobacter and Pseudomonas,which significantly enhances the electrochemical performance of the MSMFCs.Under rhamnolipids at the concentration of 200 mg kg^(-1)in sediment,the anode specific capacitance(401.45 Fm^(-2)),exchange current density(4.87×10^(-2)mAm^(-2)),and cell maximum power density(140.24 mWm^(-2))increase by 2.50,38.65,and 2.11 times,respectively,in comparison with its natural sediment.And the oil degradation rate(40.06%)was higher than the blank(17.55%).It demonstrates that the synergistic effect between electrochemical catalytic degradation and emulsifying solubilization of rhamnolipids surfactant directly accelerates the degradation of petroleum in marine sediment,which will provide a novel method and theoretical guidance for in-situ degradation and efficient removal of crude petroleum on ocean floor.
基金supported by the National Natural Science Foundation of China(Nos.U1806216,41877372)the CNPC scientific research and technological development project(No.2016D-4610)+1 种基金the Tianjin S&T Program(Nos.17ZXSTSF00050,17PTGCCX00240,16YFXTSF00520)the 111 program,Ministry of Education,China(No.T2017002)
文摘Biochar (BC) and rhamnolipid (RL) is used in bioremediation of petroleum hydrocarbons,however,the combined effect of BC and RL in phytoremediation has not been studied until now.In this paper,the phytoremediation of petroleum hydrocarbon-contaminated soil using novel plant Spartina anglica was enhanced by the combination of biochar (BC) and rhamnolipid (RL).Samples of petroleum-contaminated soil (10,30 and 50 g/kg) were amended by BC,BC+ RL and rhamnolipid modified biochar (RMB),respectively.After 60 day's cultivation,the removal rate of total petroleum hydrocarbons (TPHs) for unplanted soil (UP),planted soil (P),planted soil with BC addition (P-BC),planted soil with BC and RL addition (P-BC + RL) and planted soil with addition ofRMB (P-RMB) were 8.6%,19.1%,27.7%,32.4% and 35.1% in soil with TPHs concentration of 30 g/kg,respectively.Compared with UP,the plantation of Spartina anglica significantly decreased the concentration of C8-14 and tricyclic PAHs.Furthermore,the application of BC and RMB alleviated the toxicity of petroleum hydrocarbons to Spartina anglica via improving plant growth with increasing plant height,root vitality and total chlorophyll content.High-throughput sequencing result indicated that rhizosphere microbial community of Spartina anglica was regulated by the application of BC and RMB,with increase of bacteria and plant mycorrhizal symbiotic fungus in biochar and RMB amended soil.
基金Project (No. 2006C100105) supported by the Ningbo Scientific Research Project, China
文摘In this work,rhamnolipid production was investigated using waste frying oil as the sole carbon source. By culture in shaking flasks,a naturally isolated strain synthesized rhamnolipid at concentration of 12.47 g/L and its mutant after treatment by UV light increased this productivity to 24.61 g/L. Fermentation was also conducted in a 50 L bioreactor and the productivity reached over 20 g/L. Hence,with a stable and high productive mutant strain,it could be feasible to reuse waste frying oil for rhamnolipid production on industrial scale.
基金Project supported by Science Foundation from China Petroleum andChemical Corporation, China
文摘The potential biodegradation of crude oil was assessed based on the development of a fermentative process with a strain of Pseudomonas aeruginosa which produced 15.4 g/L rhamnolipids when cultured in a basal mineral medium using glycerol as a sole carbon source. However, neither cell growth nor rhamnolipid production was observed in the comparative culture system using crude oil as the sole carbon source instead. As rhamnolipid, an effective biosurfactant, has been reported to stimulate the biodegradation of hydrocarbons, 1 g/L glycerol or 0.22 g/L rhamnolipid was initially added into the medium to facilitate the biodegradation of crude oil. In both situations, more than 58% of crude oil was degraded and further converted into accumulated cell biomass and rhamnolipids. These results suggest that Pseudomonas aeruginosa could degrade most of crude oil with direct or indirect addition of rhamnolipid. And this conclusion was further supported by another adsorption experiment, where the ad-sorption capacity of crude oil by killed cell biomass was negligible in comparison with the biologic activities of live cell biomass.
基金supported by the Fundamental Research Funds for the Central Universities(No.2018XKQYMS12)the Program for the National Natural Science Foundation of China(Nos.51778612 and 51974314)the Natural Science Foundation of Jiangsu Province(No.BK20191480)。
文摘Biotrickling filters(BTFs) for hydrophobic chlorobenzene(CB) purification are limited by mass transfer and biodegradation. The CB mass transfer rate could be improved by 150 mg/L rhamnolipids. This study evaluated the combined use of Fe^(3+) and Zn^(2+) to enhance biodegradation in a BTF over 35 day. The effects of these trace elements were analysed under different inlet concentrations(250, 600, 900, and 1200 mg/L) and empty bed residence times(EBRTs;60, 45, and 32 sec). Batch experiments showed that the promoting effects of Fe^(3+)/Zn^(2+) on microbial growth and metabolism were highest for 3 mg/L Fe^(3+) and 2 mg/L Zn^(2+), followed by 2 mg/L Zn^(2+), and lowest at 3 mg/L Fe^(3+). Compared to BTF in the absence of Fe^(3+) and Zn^(2+), the average CB elimination capacity and removal efficiency in the presence of Fe^(3+) and Zn^(2+) increased from 61.54 to 65.79 g/(m 3 hr) and from 80.93% to 89.37%, respectively, at an EBRT of 60 sec. The average removal efficiency at EBRTs of 60, 45, and 32 sec increased by 2.89%, 5.63%, and 11.61%, respectively. The chemical composition(proteins(PN), polysaccharides(PS)) and functional groups of the biofilm were analysed at 60, 81, and 95 day. Fe^(3+) and Zn^(2+) significantly enhanced PN and PS secretion, which may have promoted CB adsorption and biodegradation. High-throughput sequencing revealed the promoting effect of Fe^(3+) and Zn^(2+) on bacterial populations. The combination of Fe^(3+) and Zn^(2+) with rhamnolipids was an efficient method for improving CB biodegradation in BTFs.
基金Project (No. 56310503014) supported by the Department of Education of Zhejiang Province, China
文摘Oily wastewater generated by various industries creates a major ecological problem throughout the world. The tra- ditional methods for the oily wastewater treatment are inefficient and costly. Surfactants can promote the biodegradation of pe- troleum hydrocarbons by dispersing oil into aqueous environment. In the present study, we applied rhamnolipid-containing cell-free culture broth to enhance the biodegradation of crude oil and lubricating oil in a conventional aerobically-activated sludge system. At 20 ℃, rhamnolipids （11.2 mg/L） increased the removal efficiency of crude oil from 17.7% （in the absence of rham- nolipids） to 63%. At 25 ~C, the removal efficiency of crude oil was over 80% with the presence of rhamnolipids compared with 22.3% in the absence of rhamnolipids. Similarly, rhamnolipid treatment （22.5 mg/L） for 24 h at 20℃ significantly increased the removal rate of lubricating oil to 92% compared with 24% in the absence of rhamnolipids. The enhanced removal of hydrocarbons was mainly attributed to the improved solubility and the reduced interfacial tension by rhamnolipids. We conclude that a direct application of the crude rhamnolipid solution from cell culture is effective and economic in removing oily contaminants from wastewater.
基金supported by“Twelfth five-year”National Science and Technology Support Program(2012BAC11B07)National Natural Science Foundation of China(51664024)+1 种基金Outstanding Doctoral Dissertation Project Funding of Jiangxi University of Science and Technology(YB2016003)Talent Project of Jiangxi Province's Innovation-drive“5511”Program(20165BCB18013)
文摘The effective leaching of rare earth elements（La, Ce, Y and Eu） from simulated contaminated soil using bio-surfactant was investigated in a lab-scale column leaching experiment, where anionic biosurfactant rhamnolipid and non-ionic biosurfactant saponin were used as washing solutions. Soil properties and the rare earth element fractions were analysed to define the effect of leaching on soil and elemental speciation. Column leaching results showed that saponin solution was more effective than rhamnolipid in the removal of the four rare earth elements tested, with the accumulative removal efficiency of La, Ce, Y and Eu following flushing with 400 mL of 25 g/L saponin, reaching 35.258%, 26.072%, 31.476% and 30.849%, respectively. The change in REE speciation showed that REE removed from soils were mainly derived from the acid-soluble and residual fractions released when rhamnolipid solution was used as a leaching agent. However, for saponin leaching, removed REE amounts were derived from acid-soluble and reducible fractions. Complexation interactions were identified between saponin and REEs, according to infrared spectroscopy and ion exchange data, with saponin complexing with La, Ce, Y, and Eu at a complex ratio of 1：1.
文摘Interfacial properties rhamnolipids from an extract produced by a strain of Pseudomonas aeruginosa were analyzed in this study. The extract of rhamnolipid was characterized by surface tension in different conditions;interfacial tension with different hydrocarbons;critical micelle concentration under different pH and temperatures;particle size and emulsification capacity using laser light profiling. It was observed that the rhamnolipids extract are sensitive to variations in pH, thermostable and function as good emulsificant for emulsification of methyl methacrylate. The emulsion stability order in function of the oil phase was methyl methacrylate > emulsions of castor oil > emulsion n-heptane > emulsion toluene > emulsion hexadecane > octane emulsion. The data presented show that rhamnolipid extracts may be used to formulate stable emulsions of methyl methacrylate. This process can be used to do nano/microsphere of polymethyl methacrylate.
基金This work was supported in part by Grant N00014-12-1-0496 from the Office of Naval Researcha subcontract with the Western Center for Agricultural Health and Safety(NIOSH grant 2U54OH007550)
文摘In highly urbanized areas,pollution from anthropogenic activities has compromised the integrity of the land,decreasing soil availability for agricultural practices.Dibenzothiophene(DBT)is a heterocyclic aromatic hydrocarbon frequently found in urbanized areas,and is often used as a model chemical to study the microbial transformation of pollutants.The potential for human exposure and its health risk makes DBT a chemical of concern;thus,it needs to be environmentally managed.We utilized glycerol to stimulate Burkholderia sp.C3 in order to degrade DBT in respect to①DBT biodegradation kinetics,②bacterial growth,③rhamnolipid(RL)biosynthesis,and④RL secretion.Under an optimum glycerol-to-DBT molar ratio,the DBT biodegradation rate constants increased up to 18-fold and enhanced DBT biodegradation by 25%–30%at day 1 relative to cultivation with DBT alone.This enhancement was correlated with an increase in bacterial growth and RL biosynthesis.Proteomics studies revealed the enzymes involved in the upper and main steps of RL biosynthesis.The RL congeners Rha-C10-C10,Rha-Rha-C10-C10,Rha-Rha-C10-C12,and Rha-Rha-C12-C12 were identified in the medium supplemented with glycerol and DBT,whereas only Rha-C12-C12 was identified in cultures without glycerol or with RL inhibitors.The studies indicated that glycerol enhances DBT biodegradation via increased RL synthesis and bacterial growth.The results warrant further studies of environmental biostimulation with glycerol to advance bioremediation technologies and increase soil availability for agricultural purposes.
基金Project(108100) supported by the Key Program for Science and Technology Research of Ministry of Education of ChinaProjects(50978087, 50908081) supported by the National Natural Science Foundation of China+1 种基金Project(531107011019) supported by the Hunan University Graduate Education Innovation Program, ChinaProject(CX2010B157) supported by the Hunan Provincial Innovation Foundation for Postgraduate students, China
文摘Rhamnolipid production by Pseudomonas aeruginosa ATCC 9027 with waste frying oil as sole carbon source was studied using response surface method. Cultures were incubated in shaking flask with temperature, NO3- and Mg2+ concentrations as the variables. Meanwhile, fed-batch fermentation experiments were conducted. The results show that the three variables are closely related to rhamnolipid production. The optimal cultivation conditions are of 6.4 g/L NaNO3 , 3.1 g/L MgSO4 at 32 ℃, with the maximum rhamnolipid production of 6.6 g/L. The results of fed-batch fermentation experiments show that feeding the oil in two batches can enhance rhamnolipid production. The best time interval is 72 h with the maximum rhamnolipid production of 8.5 g/L. The data are potentially useful for mass production of rhamnolipid on oil waste with this bacterium.
基金Projects(50978087,51009063,50978088)supported by the National Natural Science Foundation of China
文摘An environment friendly bio-surfactant of rhamnolipid(RL) was used as a solvent. The enzymatic reaction of oleic acid catalyzed by lipase and lignin peroxidase(lip) was evaluated. The optimum conditions of enzymatic reaction catalyzed by lipase(lip) were water to amphiphile molar ratio of 30(20), RL of 60(60) critical micelle concentration(CMC), pH of 7.0(3.0) and temperature of 40(30) °C, respectively. The change of enzyme conformation indicates that, for catalytic of lipase, water content is the most important factor of the enzymatic reaction of oleic acid, and p H for lip. With individual optimum conditions, the enzymatic efficiency of oleic acid catalyzed by lipase is higher than that by lip. In the presence of ethanol, the enzymatic reaction of oleic acid catalyzed by lipase suits Ping-Pong Bi-Bi mechanism. As an alternative to chemical reversed micelles, the RL reversed micelles are promising methods to enzymatic reaction of oleic acid.
基金the National Natural Science Fund Projects of China(Nos.41371314 and 51202229)the Key Research&Development Project of Shandong Province(No.2017GHY15117)+1 种基金the Major Focus Project of Henan Academy of Sciences(No.19ZD08001)the Fundamental Research Funds for the Central Universities(No.18JK02025).
文摘Hydrophobic organic compounds(HOCs)and heavy metals(HMs)are toxins that usually coexist in natural environments.Due to the differences in their properties,it remains challenging to simultaneously remove HMs and HOCs.In this study,the removal of phenanthrene(Phe)and lead(Pb)from co-contaminated soils by single rhamnolipid(RL)and mixed RL-sophorolipid(SL)biosurfactants were evaluated via soil column experiments.Biosurfactant micelle sizes were determined by dynamic light scattering,and the mechanisms of micelle solubilization were studied.The effects of biosurfactant concentrations,pH,washing agent salinity and the ageing time of polluted soils on Phe and Pb desorption efficiencies were also assessed.The substantial removal of Phe and Pb using mixed RL-SL systems,when molar fractions of RLs were 0.7,was attributed to large mixed micelle formation and lower sorption losses of these systems.The optimal pH value was 6.0,while Phe desorption was favoured at high RLs and low ionic strengths.However,the RLs concentration and ionic strength had no obvious influence on Pb removal.In addition,both Phe and Pb desorption decreased with increased ageing of the polluted soils.Combined RL-SL biosurfactants can be effective for simultaneously removing HOCs and HMs from polluted soils.
文摘Biosurfactants were synthesized by Pseudomonas aeruginosa （P.A.）, using sugar cane molasses as carbon source. Assays were conducted in a shaker with agitation speed of 200 rpm, temperature of 38 ℃ and aeration ratio （Vm/Vf） of 0.4 and 0.6. A concentration of 3.0% was used for the carbon and energy source （molasses） and of 0.3% for the nitrogen source （NaNO3）. Samples were removed at regular times until 96 hours of cultivation. The reduction in surface tension was measured using the ring method; cell concentration was obtained by the dry mass and substrate consumption by the DNS method. The metabolite produced was extracted and quantified by the thioglycolic method. The results showed a maximum surface tension reduction of 46.57% after 60 h, 3.63 g/L of biomass after 8 h （μXmax =0.15 h^-1）, 79.60% of substrate consumption （μs= 0.67 h-1） and 4.47 g/L of rhamnolipid （μp=0.029 h^-1）.
文摘Forecasting the properties of nanoemulsions without engaging in expensive and time-consuming experimental research can yield significant benefits across multiple applications.This study examines the capability of machine learning to precisely forecast the interfacial tension and viscosity of crude oilwater nanoemulsions stabilized by rhamnolipid biosurfactant.Four artificial neural network models were created and assessed for nanoemulsions composed of different concentrations of crude oil and biosurfactants.The performance evaluation of the artificial neural network models demonstrated mean squared error values below 2.26E-03 and coefficients of determination greater than 0.999,signifying exceptional predictive accuracy.The mean overall deviation for all models was determined to be around 0.004%,indicating a negligible divergence from experimental results.The findings indicate that the developed artificial neural network models can accurately and reliably predict interfacial tension and viscosity values,providing an efficient alternative to experimental methods,with potential applications in optimizing nanoemulsion formulations for industrial purposes.
文摘Rhamnolipids are one of the most effective biosurfactants that are of great interest in industrial applications such as enhancing oil recovery, health care, cosmetics, pharmaceutical processes, food processing, detergents for protein folding, and bioremediation due to their unique characteristics such as low toxicity, surface active property to reduce surface/interfacial tensions, and excellent biodegradability. The genes and metabolic path- ways for rhamnolipid synthesis have been well elucidated, but its cost-effective production is still challenging. Pseudomonas aeruginosa, the most powerful rhamnolipid producer, is an opportunistic pathogen, which limits its large scale production and applications. Rhamnolipid production using engineered strains other than Pseudomo- nas aeruginosa such as E. coli and Pseudomonas putida has received much attention. The highest yield of rhamnolipids is achieved when oil-type carbon sources are used, but using cheaper and renewable carbon sources such as lignocellulose would be an attractive strategy to reduce the production cost of rhamnolipids for various industrial applications.
基金grateful to Higher Education Commission(HEC),Pakistan for funding under the National Research Program for Universities(NRPU)Vide Grant No.5378.
文摘Milk fat globule membrane (MFGM) phospholipids-based nanostructures were developed and their functionalization with rhamnolipids (RLs) was carried out to enhance the preservation of cheese against resistant foodborne pathogens i.e.,Listeria monocytogenes and Escherichia coli .Void (without nisin) and nisin-loaded RLs functionalized MFGM nanostructures (RLs-MFGM-NS) were fabricated by ultrasonication-assisted self-assembly method.Cubic morphology of void and loaded RLs-MFGM-NS and pristine MFGM nanostructures (MFGM-NS) was observed under scanning electron microscopy (SEM),which indicated uniform size ranging from 43 nm (void RLs-MFGM-NS) to 194 nm (loaded RLs-MFGM-NS).FTIR analyses confirmed the electrostatic interaction,predominantly H-bonding and linkage of carboxyl ester group of MFGM with C–H group in RLs after functionalization of NS.Furthermore,quantitative antimicrobial assay on cheese slices confirmed the broad-spectrum potential of intrinsically active nanostructures (due to RLs) having synergistic activity with nisin against L.monocytogenes and E.coli .Hence,nisin-loaded RLs-MFGM-NS can be applied as promising bioactive additives for sustained preservation of cheese.
文摘Rhamnolipids are a class ofbiosurfactants that have a great potential to be used in industries. Five proteins/enzymes, namely RhlA, RhlB, RhlC, RhlG and RhlI, are critical for the production of rhamnolipids in Pseudomonas aeruginosa. Four of the 5 proteins except RhlC were successfully over-expressed in E. coli and three of them （RhlA, RhlB and RhlI） were purified and obtained in milligram quantities. The purified proteins were shown to be folded in solution. Homology models were built for RhlA, RhlB and RhlI. These results lay a basis for further structural and functional characterization of these proteins in vitro to favor the construction of super strains for rhamnolipids production.
文摘Background:Traditional synthetic surfactants used in shampoos,such as sodium lauryl sulfate(SLS),raise significant environmental and dermatological concerns due to their poor biodegradability,high irritation potential,and petrochemical origin.In contrast,biosurfactants offer eco-friendly,skin-compatible alternatives that align with green chemistry principles and support sustainable personal care.Objective:This review aims to critically evaluate the functional,environmental,and dermatological performance of microbial biosurfactants,particularly rhamnolipids and sophorolipids,as sustainable alternatives to synthetic surfactants in shampoo formulations.Methods:A comprehensive analysis of published research was conducted to assess biosurfactant properties,production methods,comparative cleansing and foaming efficacy,biodegradability,skin compatibility,and formulation challenges.The review includes physicochemical data,in vitro and in vivo performance metrics,and case examples from commercial products.Results:Rhamnolipids and sophorolipids demonstrated sebum removal efficiencies of 85–95%,foam volume retention above 75%,and biodegradability rates of 60–95%within 7–14 days.They exhibited lower irritation indices(<1.0)and caused≤10%protein loss in skin models,in contrast to SLS,which caused up to 40%protein denaturation.However,biosurfactant integration is challenged by higher costs($20–40/kg),pH sensitivity,and limited consumer familiarity.Formulation strategies such as hybrid surfactant systems,pH buffering,and synergistic blends were reviewed to overcome these barriers.Conclusion:Biosurfactants offer a promising path toward microbiome-friendly,sustainable shampoos without compromising cleansing or sensory performance.To enable broader adoption,efforts must focus on improving fermentation efficiency,optimizing formulation stability,and educating consumers.Strategic positioning of biosurfactants based on their unique functional profiles can help meet evolving demands for eco-conscious and dermatologically gentle hair care.
