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1.
《Process Biochemistry》2010,45(11):1795-1799
Microbial production and isolation of biosurfactants was studied. The production of lipopeptides surfactin and fengycin was performed by free and immobilized aerobic cells of Bacillus subtilis ATCC 21332. After preliminary tests with 5 polymer materials, the particles of polypropylene foamed with powder activated carbon (PPch) were selected for lipopeptides production for their thermal and mechanical stability and for the high colonizing effect. To avoid foaming during biosurfactant production, biofilm grown on solid floating support was aerated by air injected over the surface of cultural medium. The synthesis of both lipopeptides and especially of the fengycin was greatly enhanced by the immobilization. The relationship between support wettability, colonization of the cells, and lipopeptide production was discussed. Extraction behaviour of the lipopeptides into alkanes was studied. The distribution ratio of surfactin was found to be higher than this of fengycin at the same conditions and the n-heptane was more efficient solvent for both lipopeptides. Kinetics of surfactin recovery from fermentation broth applying batch pertraction in a rotating discs contactor was studied. Lipopeptide was successfully extracted (more than 75% in the first hour) using n-heptane as liquid membrane and a 0.2 mol L−1 phosphate buffer solution (pH ∼ 7.3) as receiving solution. However, the stripping of the organic liquid and surfactin accumulation into the receiving phase were less efficient. 相似文献
2.
François Coutte Didier Lecouturier Saliha Ait Yahia Valérie Leclère Max Béchet Philippe Jacques Pascal Dhulster 《Applied microbiology and biotechnology》2010,87(2):499-507
Surfactin and fengycin are lipopeptide biosurfactants produced by Bacillus subtilis. This work describes for the first time the use of bubbleless bioreactors for the production of these lipopeptides by B. subtilis ATCC 21332 with aeration by a hollow fiber membrane air–liquid contactor to prevent foam formation. Three different configurations
were tested: external aeration module made from either polyethersulfone (reactor BB1) or polypropylene (reactor BB2) and a
submerged module in polypropylene (reactor BB3). Bacterial growth, glucose consumption, lipopeptide production, and oxygen
uptake rate were monitored during the culture in the bioreactors. For all the tested membranes, the bioreactors were of satisfactory
bacterial growth and lipopeptide production. In the three configurations, surfactin production related to the culture volume
was in the same range: 242, 230, and 188 mg l−1 for BB1, BB2, and BB3, respectively. Interestingly, high differences were observed for fengycin production: 47 mg l−1 for BB1, 207 mg l−1 for BB2, and 393 mg l−1 for BB3. A significant proportion of surfactin was adsorbed on the membranes and reduced the volumetric oxygen mass transfer
coefficient. The degree of adsorption depended on both the material and the structure of the membrane and was higher with
the submerged polypropylene membrane. 相似文献
3.
Omar Chtioui Krasimir Dimitrov Frédérique Gancel Pascal Dhulster Iordan Nikov 《Process Biochemistry》2012,47(12):2020-2024
Microbial production of two biosurfactants, fengycin and surfactin, by Bacillus subtilis ATCC 21332 in a rotating discs bioreactor was studied. Simultaneous production of these lipopeptides was performed by free and cells immobilized on the surfaces of rotating discs. The aeration applied on surface allowed a non-foaming fermentation process and an important production of lipopeptides for low microbial growth in the culture medium. It was demonstrated that the selectivity of lipopeptides synthesis could be modified varying operating conditions and that the cells immobilization improved greatly fengycin synthesis. The maximal concentration of fengycin and surfactin obtained were 838 mg L?1 and 212 mg L?1, respectively. The development of this bubble-less process could advance the scale-up of the fermenters for production of biosurfactants. 相似文献
4.
Xianqing Huang Zhanyong Wei Xiaoping Gao Shujing Yang Yanhong Cui 《International journal of peptide research and therapeutics》2008,14(2):89-95
In this paper, the sterilization of surfactin and fengycin to Bacillus cereus was observed, and the optimization of the inactivation of surfactin and fengycin to spores of B. cereus by a response surface methodology was studied. Results showed that surfactin and fengycin had high sterilization to B. cereus, whose minimal inhibitory concentration was 31.25 μM and 62.5 μM respectively. The optimization result indicated that spores
of B. cereus could be inactivated by two orders of magnitude when the temperature was 20.41°C, the action time was 21.13 h, and the concentration
(surfactin/fengycin molar ratio 1:1) was 54.20 μM. 相似文献
5.
The research investigated the nitrification characteristics of two different immobilization methods: nitrifier encapsulation
in polyethylene glycol (PEG) gel pellets and nitrifier biofilm attachment on elastic plastic filler. The two carriers were
placed in identical reactors. They reached a maximum nitrification rate of 39 and 25 mgN/L·h 30 days after start-up. The results
showed that the nitrification efficiency in the PEG reactor was higher than in the biofilm reactor under the same conditions.
Variations in temperature decreased the nitrification rate by approximately 55% in the PEG reactor from 28 to 8°C, while 74.2%
in the biofilm reactor. When the COD loading rate was increased to 0.8 kg/m3 day, the nitrification efficiency in the biofilm reactor dropped sharply to 23%, and that of PEG reactor remained over 80%.
PEG pellets with a high nitrification rate under all conditions showed promise as an immobilization medium, and are likely
to be utilized in the nitrification of high-strength ammonia and COD wastewater during long-term operation. 相似文献
6.
François Coutte Didier Lecouturier Valérie Leclère Max Béchet Philippe Jacques Pascal Dhulster 《Process Biochemistry》2013,48(1):25-32
Recently, a bubbleless membrane bioreactor (BMBR) has been successfully developed for biosurfactant production by Bacillus subtilis [1]. In this study, for the first time, continuous culture were carried out for the production of surfactin in a BMBR, both with or without a coupled microfiltration membrane. Results from continuous culture showed that a significant part of biomass was immobilized onto the air/liquid membrane contactor. Immobilized biomass activity onto the air/liquid membrane contactor was monitored using a respirometric analysis. Kinetics of growth, surfactin and primary metabolites production were investigated. Planktonic biomass, immobilized biomass and surfactin production and productivity obtained in batch culture (3 L) of 1.5 days of culture were 4.5 g DW, 1.3 g DW, 1.8 g and 17.4 mg L?1 h?1, respectively. In continuous culture without total cell recycling (TCR), the planktonic biomass was leached, but immobilized biomass reached a steady state at an estimated 6.6 g DW. 11.5 g of surfactin was produced after 3 days of culture, this gave an average surfactin productivity of 54.7 mg L?1 h?1 for the continuous culture, which presented a surfactin productivity of 30 mg L?1 h?1 at the steady state. TCR was then investigated for the continuous production, extraction and purification of surfactin using a coupled ultrafiltration step. In continuous culture with TCR at a dilution rate of 0.1 h?1, planktonic biomass, immobilized biomass, surfactin production and productivity reached 7.5 g DW, 5.5 g DW, 7.1 g and 41.6 mg L?1 h?1 respectively, after 2 days of culture. After this time, biomass and surfactin productions stopped. Increasing dilution rate to 0.2 h?1 led to the resumption of biomass and surfactin production and these values reached 11.1 g DW, 10.5 g DW, 7.9 g and 110.1 mg L?1 h?1, respectively, after 3 days of culture. This study has therefore shown that with this new integrated bioprocess, it was possible to continuously extract and purify several grams of biosurfactant, with purity up to 95%. 相似文献
7.
《Process Biochemistry》2014,49(10):1699-1707
This study reports the potential of a marine bacterium, Bacillus mojavensis A21, to produce lipopeptide biosurfactants. The crude lipopeptide mixture was found to be very effective in reducing surface tension to 31 mN m−1. PCR experiments using degenerate primers revealed the presence of nonribosomal peptide synthetases genes implied in the biosyntheses of fengycin and surfactin. Matrix-Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF-MS) performed on whole cells of B. mojavensis A21 confirmed the presence of lipopeptides identified as members of surfactin and fengycin families. Further, a detailed analysis performed by MALDI-TOF-TOF revealed the presence of pumilacidin compounds. The crude lipopeptide mixture was tested for its inhibitory activity against Gram-positive and Gram-negative bacteria, and fungal strains. It was found to display significant antimicrobial activity. Strain A21 lipopeptide mixture was insensitive to proteolytic enzymes, stable between pH 3.0 and 11.0, and resistant to high temperature. Production of lipopeptides is a characteristic of several Bacillus species, but to our knowledge this is the first report involving identification of pumilacidin, surfactin and fengycin isoforms in a B. mojavensis strain. 相似文献
8.
A modified electro-transformation method for Bacillus subtilis and its application in the production of antimicrobial lipopeptides 总被引:1,自引:0,他引:1
A modified electroporation method using trehalose is presented for the transformation of Bacillus subtilis. The new method improved the transformation efficiency of B. subtilis nearly 2,000-fold compared with the usual method, giving 4 × 105 transformants/μg DNA. Using this method, B. subtilis was engineered to improve production of antimicrobial lipopeptides and produced 1.8-fold more surfactin and 2.9-fold more
fengycin. 相似文献
9.
Ławniczak Łukasz Kaczorek Ewa Olszanowski Andrzej 《World journal of microbiology & biotechnology》2011,27(5):1183-1188
Recent biodegradation researches are focused on improving the deterioration efficiency and maintaining the stability of microbial
activity during the process. Immobilizing bacterial cells by using the adhesive method is a simple way to achieve both objectives.
The purpose of this study was to evaluate how the immobilization of bacterial cells by the biofilm forming method influences
the biodegradation efficiency of two different bacterial consortia—low diesel oil degraders (base deterioration efficiency < 40%)
and high phenol degraders (base deterioration efficiency > 90%). The degradation tests were carried out on four different
carriers (expanded clay pellets, polypropylene, polyvinyl chloride rings and paperboard). The obtained results show that biofilms
may considerably increase the efficiency of low degraders. The best diesel oil deterioration (80%) was achieved when paperboard
was used as a carrier. However, the immobilization of high degraders did not significantly influence their base biodegradation
potential. A 6% increase was noted only for the expanded clay pellets. 相似文献
10.
《Journal of Molecular Catalysis .B, Enzymatic》2010,65(3-4):172-176
A series of porous polyurethane (PU) microparticles from poly(vinyl alcohol) (PVA) and hexamethylene diisocyanate (HMDI) using different ratios of components were obtained by one step method. Molar compositions of PU microparticles were estimated by determination of nitrogen, isocyanate and hydroxyl groups. PU carriers which were synthesized using optimal initial molar ratios of PVA and HMDI were applied for immobilization of maltogenase (MG) from Bacillus stearothermophilus. Immobilized enzyme exhibited higher catalytic activity and enhanced temperature stability in comparison with the native MG. Maximal loading 7.78 mg/g wet carrier was reached when PU microparticles with initial molar ratio of PVA and HMDI = 1:3 was used as a carrier for immobilization. The high efficiency of immobilization (EI) was obtained using PU microparticles when initial molar ratio of HMDI and PVA was 1:1–1:10. High stability of MG immobilized onto PU microparticles during storage was demonstrated. Immobilized starch hydrolyzing enzyme was successfully tested in batch and column type reactors for hydrolysis of potato starch. MG immobilized onto PU enables easy separation from the reaction medium and reuse of the immobilized preparation over seven reaction cycles in bath operation and at least three cycles in column type reactor. 相似文献
11.
In this study, a method was developed to immobilize silver onto polypropylene (PP) membrane surfaces for improved anti-biofouling performance. A commercial PP membrane was first grafted with the thiol functional groups, and then silver ions were immobilized onto the PP membrane surface through coordinating with the thiol groups. The immobilized silver was found to be very stable, with only ~1.1% of the immobilized silver being leached out during a leaching test. The surface of the modified membrane (PPS-Ag) was examined with ATR-FTIR and XPS analysis, which verified the successful grafting of the thiol groups and the coordination of silver ions on the membrane surface. The surface properties of the membrane were also characterized by SEM, AFM and water contact angle measurements. The PPS-Ag membrane was found to have a smoother and more hydrophilic surface than the PP membrane. Both Gram-negative bacteria, Escherichia coli, and Gram-positive bacteria, Staphylococcus aureus, were used to evaluate the antibacterial and anti-biofouling performance of the PPS-Ag membrane. From disk diffusion experiments, the PPS-Ag membrane exhibited the capability of inhibiting the growth of both the Gram-negative and Gram-positive bacteria tested. The anti-biofouling performance of the membrane was assessed by immersion in a mixed suspension of E. coli and S. aureus and filtration tests. The PPS-Ag membrane showed a stable and significantly enhanced anti-biofouling performance as compared with the PP membrane. The results in this study demonstrate that biofouling of a PP membrane can be sufficiently overcome through immobilizing silver onto the membrane surface. 相似文献
12.
Omar Chtioui Krasimir Dimitrov Frédérique Gancel Pascal Dhulster Iordan Nikov 《Bioprocess and biosystems engineering》2014,37(2):107-114
Production of lipopeptides fengycin and surfactin in rotating discs bioreactor was studied. The effects of rotation velocity and the addition of agitators between the discs on volumetric oxygen transfer coefficient k L a were firstly studied in model media. Then the production of lipopeptides was also studied at different agitation conditions in the modified bioreactor (with agitators). The effect of agitation on dissolved oxygen, on submerged and immobilized biomass, on lipopeptide concentrations and yields and on the selectivity of the bioreaction was elucidated and discussed. The proposed modified rotating discs bioreactor allowed to obtain high fengycin concentrations (up to 787 mg L?1), but also better selectivity of the bioreaction towards fengycin (up to 88 %) and better yields of fengycin per glucose (up to 62.9 mg g?1), lipopeptides per glucose (up to 71.5 mg g?1), fengycin per biomass (up to 309 mg g?1) and lipopeptides per biomass (up to 396 mg g?1) than those reported in the literature. Highest fengycin production and selectivity were obtained at agitation velocity of 30 min?1. The proposed non-foaming fermentation process could contribute to the scale-up of lipopeptide fermentors and promote the industrial production of fengycin. The proposed bioreactor and bioprocess could be very useful also for the production of other molecules using bioprocesses requiring bubbleless oxygen supply. 相似文献
13.
In this paper, the sensitivity of Escherichia coli to surfactin and fengycin was observed, and the optimization of the antimicrobial activity of surfactin and fengycin to E. coli in milk by a response surface methodology was studied. Results showed that E. coli had high sensitivity to these antibiotics, whose minimal inhibitory concentrations were 15.625 μg·mL−1 and 31.25 μg·mL−1, respectively. The optimization result indicated that E. coli could be sterilized by 5 orders of magnitude when the temperature was 5.5°C, the action time was 15.8 h, and the concentration
(surfactin/fengycin weight ratio 1:1) was 14.63 μg·mL−1. 相似文献
14.
In this study, a method was developed to immobilize silver onto polypropylene (PP) membrane surfaces for improved anti-biofouling performance. A commercial PP membrane was first grafted with the thiol functional groups, and then silver ions were immobilized onto the PP membrane surface through coordinating with the thiol groups. The immobilized silver was found to be very stable, with only ~1.1% of the immobilized silver being leached out during a leaching test. The surface of the modified membrane (PPS-Ag) was examined with ATR-FTIR and XPS analysis, which verified the successful grafting of the thiol groups and the coordination of silver ions on the membrane surface. The surface properties of the membrane were also characterized by SEM, AFM and water contact angle measurements. The PPS-Ag membrane was found to have a smoother and more hydrophilic surface than the PP membrane. Both Gram-negative bacteria, Escherichia coli, and Gram-positive bacteria, Staphylococcus aureus, were used to evaluate the antibacterial and anti-biofouling performance of the PPS-Ag membrane. From disk diffusion experiments, the PPS-Ag membrane exhibited the capability of inhibiting the growth of both the Gram-negative and Gram-positive bacteria tested. The anti-biofouling performance of the membrane was assessed by immersion in a mixed suspension of E. coli and S. aureus and filtration tests. The PPS-Ag membrane showed a stable and significantly enhanced anti-biofouling performance as compared with the PP membrane. The results in this study demonstrate that biofouling of a PP membrane can be sufficiently overcome through immobilizing silver onto the membrane surface. 相似文献
15.
Yan Li Marie-Claire Héloir Xun Zhang Mareen Geissler Sophie Trouvelot Lucile Jacquens Marius Henkel Xin Su Xuewen Fang Qi Wang Marielle Adrian 《Molecular Plant Pathology》2019,20(8):1037-1050
Bacillus subtilis GLB191 (hereafter GLB191) is an efficient biological control agent against the biotrophic oomycete Plasmopara viticola, the causal agent of grapevine downy mildew. In this study, we show that GLB191 supernatant is also highly active against downy mildew and that the activity results from both direct effect against the pathogen and stimulation of the plant defences (induction of defence gene expression and callose production). High-performance thin-layer chromatography analysis revealed the presence of the cyclic lipopeptides fengycin and surfactin in the supernatant. Mutants affected in the production of fengycin and/or surfactin were thus obtained and allowed us to show that both surfactin and fengycin contribute to the double activity of GLB191 supernatant against downy mildew. Altogether, this study suggests that GLB191 supernatant could be used as a new biocontrol product against grapevine downy mildew. 相似文献
16.
Urbance SE Pometto AL Dispirito AA Denli Y 《Applied microbiology and biotechnology》2004,65(6):664-670
Continuous and repeat-batch biofilm fermentations using Actinobacillus succinogenes were performed with immobilized and suspended-cell systems. For the immobilized continuous system, plastic composite supports (PCS) containing 50% (w/w) polypropylene (PP), 35% (w/w) ground soybean hulls, 5% (w/w) dried bovine albumin, 2.5% (w/w) soybean flour, 2.5% (w/w) yeast extract, 2.5% (w/w) dried red blood cells, and 2.5% (w/w) peptone, or PP tubes (8.5 cm in length) were arranged around the agitator shaft in a grid formation. Agitation was controlled at 125 rpm and 150 rpm. Samples were taken at dilution rates of 0.2, 0.4, 0.6, 0.8, 1.0, and 1.2 h–1 and analyzed for succinic acid production and glucose consumption (g l–1). For PCS bioreactors, the highest final succinic acid concentrations (10.1 g –1, 10.4 g l–1) and percentage yields (62.6%, 71.6%) occurred at the dilution rate of 0.2 h–1. PCS disks were evaluated in a repeat-batch biofilm reactor. Suspended-cell batch fermentations were performed in flasks and a repeat-batch bioreactor. The maximum concentration of succinic acid produced was 40 g l–1. Peak succinic acid percentage yields in continuous and repeat-batch fermentations of A. succinogenes were observed in suspended-cell continuous fermentations at a dilution rate of 1.0 h–1 (76.2%) and in PCS repeat-batch fermentations with an initial glucose concentration of 40 g l–1 (86.7%). 相似文献
17.
Structural and functional characterization of gene clusters directing nonribosomal synthesis of bioactive cyclic lipopeptides in Bacillus amyloliquefaciens strain FZB42 总被引:17,自引:0,他引:17
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Koumoutsi A Chen XH Henne A Liesegang H Hitzeroth G Franke P Vater J Borriss R 《Journal of bacteriology》2004,186(4):1084-1096
The environmental strain Bacillus amyloliquefaciens FZB42 promotes plant growth and suppresses plant pathogenic organisms present in the rhizosphere. We sampled sequenced the genome of FZB42 and identified 2,947 genes with >50% identity on the amino acid level to the corresponding genes of Bacillus subtilis 168. Six large gene clusters encoding nonribosomal peptide synthetases (NRPS) and polyketide synthases (PKS) occupied 7.5% of the whole genome. Two of the PKS and one of the NRPS encoding gene clusters were unique insertions in the FZB42 genome and are not present in B. subtilis 168. Matrix-assisted laser desorption ionization-time of flight mass spectrometry analysis revealed expression of the antibiotic lipopeptide products surfactin, fengycin, and bacillomycin D. The fengycin (fen) and the surfactin (srf) operons were organized and located as in B. subtilis 168. A large 37.2-kb antibiotic DNA island containing the bmy gene cluster was attributed to the biosynthesis of bacillomycin D. The bmy island was found inserted close to the fen operon. The responsibility of the bmy, fen, and srf gene clusters for the production of the corresponding secondary metabolites was demonstrated by cassette mutagenesis, which led to the loss of the ability to produce these peptides. Although these single mutants still largely retained their ability to control fungal spread, a double mutant lacking both bacillomycin D and fengycin was heavily impaired in its ability to inhibit growth of phytopathogenic fungi, suggesting that both lipopeptides act in a synergistic manner. 相似文献
18.
Biofilm is a natural form of cell immobilization in which microorganisms attach onto solid support. In this study, a pigment-reduced
pullulan-producing strain, Aureobasidium pullulans (ATCC 201253), was used for continuous pullulan fermentation in a plastic composite support (PCS) biofilm reactor. Optimal
conditions for the continuous pullulan production were determined by evaluating the effects of the feeding medium with various
concentrations of ammonium sulfate and sucrose and dilution rate. Pullulan concentration and production rate reached maximum
(8.3 g/l and 1.33 g/l/h) when 15 g/l of sucrose, 0.9 g/l of ammonium sulfate, and 0.4 g/l of yeast extract were applied in
the medium, and the dilution rate was at 0.16 h−1. The purity of produced pullulan was 93.0%. The ratio of hyphal cells of A. pullulans increased when it was grown on the PCS shaft. Overall, the increased pullulan productivity can be achieved through biomass
retention by using PCS biofilm reactor. 相似文献
19.
Continuous lactic acid fermentation using a plastic composite support biofilm reactor 总被引:3,自引:1,他引:2
J. Cotton A. Pometto J. Gvozdenovic-Jeremic 《Applied microbiology and biotechnology》2001,57(5-6):626-630
An immobilized-cell biofilm reactor was used for the continuous production of lactic acid by Lactobacillus casei subsp. rhamnosus (ATCC 11443). At Iowa State University, a unique plastic composite support (PCS) that stimulates biofilm formation has been developed. The optimized PCS blend for Lactobacillus contains 50% (wt/wt) agricultural products [35% (wt/wt) ground soy hulls, 5% (wt/wt) soy flour, 5% (wt/wt) yeast extract, 5% (wt/wt) dried bovine albumin, and mineral salts] and 50% (wt/wt) polypropylene (PP) produced by high-temperature extrusion. The PCS tubes have a wall thickness of 3.5 mm, outer diameter of 10.5 mm, and were cut into 10-cm lengths. Six PCS tubes, three rows of two parallel tubes, were bound in a grid fashion to the agitator shaft of a 1.2-1 vessel for a New Brunswick Bioflo 3000 fermentor. PCS stimulates biofilm formation, supplies nutrients to attached and suspended cells, and increases lactic acid production. Biofilm thickness on the PCS tubes was controlled by the agitation speed. The PCS biofilm reactor and PP control reactor achieved optimal average production rates of 9.0 and 5.8 g l(-1) h(-1), respectively, at 0.4 h(-1) dilution rate and 125-rpm agitation with yields of approximately 70%. 相似文献
20.
Shitamura A Kasai A Hiramatsu N Hayakawa K Yao J Kitamura M 《Analytical biochemistry》2005,347(1):135-143
In the current study, we attempted to develop a method for bioassay-based screening of microorganisms that degrade dioxin. However, a crucial problem encountered was that the standard dioxin 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) added to bacterial medium immediately disappeared from the liquid phase due to its adsorption onto polypropylene (PP) tubes. Among other aromatic hydrocarbons, adsorption onto PP tubes was also observed in beta-naphthoflavone but not in benzo[a]pyrene. Adsorption of TCDD was observed not only onto PP tubes but also onto polystyrene, glass, and PP tubes with low affinity for DNA or protein. Silanization was not effective at preventing adsorption of TCDD. TCDD immobilized onto PP tubes was recovered by organic solvents, including ethanol, methanol, and dimethyl sulfoxide (DMSO). The elution efficiency of the immobilized TCDD by DMSO was approximately 85%. Based on these findings, screening of bacteria that degrade dioxin was attempted as follows. First, TCDD was immobilized onto PP tubes. Second, bacterial suspension was added to the tubes and incubated for biodegradation of TCDD. Third, remaining, immobilized TCDD was eluted by DMSO and subjected to a reporter bioassay to evaluate the level of TCDD. Using this method, we demonstrated successful screening of bacteria that have the potential for degradation of dioxin. 相似文献